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| 1 General | Top | |
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This glossary contains Telecom and TelORB (TSP) terms, which may be useful to know.
This document should not be regarded as official Ericsson documentation, since is is written mainly for my own use. However, if it suits your needs, feel free to use it. This glossary was initially a part of the TelORB Guidelines, but due to that it became so big, I moved it to a web page of its own and included a link to it from the TelORB Guidelines (Feb. 8, 2001). Disclaimer
Your feedback and suggestions for improving this glossary are very much appreciated; send an e-mail to Michel Sundin. If you have questions regarding TelORB, please do not send them to me, `cause I'm getting swamped. Use the No anabolic steroids were consumed during the writing of this glossary.
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| 2 Glossary | Top | |
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| A | Top of Glossary |
AAA Authentication, Authorization and Accounting A server that verifies the identity of a user or equipment, grants the use of a service or a resource and collects information for analysis, auditing, billing, cost allocation etc. A-bis interface SS7 term. See LAPD. ABS Alternate Billing Service An alternative method of billing, other than billing the calling subscriber, e.g. freephone or premium rate services. AC Authentication Center (TDMA) A functional piece of the HLR used to authenticate the user of mobile station equipment and to protect each subscriber or subscription number from unauthorized access. The AC is a server that provides encryption and verification functions to protect a wireless network from fraudulent use. ACM Address Complete Message (SS7 term) ACM is an acknowledgement message that is used in both TUP and ISUP. It is a signal indication that all address signals required for routing the call to the called party have been received. AD Amendment Directive (Ericsson term) TelORB used the term 'AD' as a name of a TelORB release, e.g. AD12. After TelORB release AD12 the term 'AD' changed to 'R' (as in Release), e.g. TelORB release R13. Address indicator An SS7 term for a single octet field indicating the type of address format in the address field of an SCCP message. ADSL Asymmetrical Digital Subscriber Line Higher capacity on the link to the user than from the user. Also see DSL. AE Application Entity (SS7 term) The MAP which is used for signalling in a mobile network, is divided into 5 AEs each of which is concerned with communication between MAP and different elements in the mobile network. The 5 AEs are: MAP-MSC, MAP-VLR, MAP-HLR, MAP-EIR and MAP-AUC. Each AE consists of a number of Application Service Elements (ASEs). See MAP for further info. Also see ASE. AIN Advanced Intelligent Network Bellcore's IN concept which is based on research undertaken in the U.S. A-interface An IN term for the interface between the MSC and the BSS. Also see BSSAP. Air-interface The Air-interface, also known as the Um-interface, is the interface (protocol) between the BTS and the MS in mobile networks. Same as LAPDm. Also see GSM, BTS, LAPDm, MS, Protocol, Um-interface. ALI ATM Line Interface AMPS Advanced Mobile Phone Service ANSI American National Standards Institute A United States-based organization that develops standards and defines interfaces for telecommunications, including ISDN. Also see ETSI. Answer message An SS7 term for a message, in the ISUP, which is sent in the backward direction to indicate that the call has been answered. AP Application Part (SS7 term) (Can be seen as protocols) An AP is any part of the SS7 node which accesses the SS7 network through the TCAP. The parts of the SS7 node that generate the signalling are called APs. Additional parts added to the node to cater for new applications, e.g. the Mobile Applications Part (MAP). APs also generate, transmit and receive inter-exchange signalling messages. Two functions of the APs are to generate messages relating to mobile telephony and to O&M functions in the network. AP | UP ------- MTP Examples of SS7 application independent parts (APs): TCAP, ISP and SCCP (I.e. functions which are common to all applications are performed by TCAP, ISP and SCCP.) Examples of SS7 application specific parts (APs): MAP, INAP and OMAP. (I.e. application specific functions are performed by APs, e.g. MAP, INAP and OMAP.) The following APs are used in GSM: - Mobile Application Part (MAP) - Base Station System Application Part (BSSAP) - Direct Transfer Application Part (DTAP) - Base Station System Management Application Part (BSSMAP) Also see SS7, SP, UP, MTP, TCAP, ISP, SCCP, NSP, MAP, INAP, OMAP, GSM. API Application Program Interface (Application Programming Interface) Application Layer The Application Layer (layer 7 of the OSI model) provides services for support of the user's application process and for control of all communication between applications. These services include e.g. protocols for file transfer, message handling and directory services. The Application Layer provides services for support of the user's application process and for control of all communication between applications. Also see OSI. ASE Application Service Management (SS7 term) An ASE function consists of one or several operations to perform tasks between MAP entities, e.g. location updating between a VLR and an HLR in the mobile network. Each AE consists of a number of Application Service Elements (ASEs). These ASEs are grouped into: - specific ASEs, those used in a specific MAP AE only. - common ASEs, those used in all MAP AEs. E.g. TCAP is a common ASE which resides in all MAP AEs. Also see MAP, AE. ATM Asynchronous Transfer Mode AUC Authentication Center (GSM) One of the SS components. The AUC is a database, in the GSM network, which provides authentication and encryption parameters required to ensure the strict confidentiality of each call. The AUC provides the HLR with authentication parameters and ciphering key, which are both used for security reasons. Also see SS, GSM. AXmp SPARCengine Ultra AXmp The AXmp is an external (non TelORB) support processor. It is a multi CPU Ultra Sparc computer in a standard rack-mountable packaging. For more information, see http://www.sun.com/microelectronics/SPARCengineUltraAXmp/. In a TelORB system the task of the AXmp is to terminate the SS7 signalling. Since the AXmp is considered to be a part of the TelORB zone it has to be supervised by TelORB, and a TelORB alarm should be sent if a hardware problem is detected. |
| B | Top of Glossary |
BCSM Basic Call State Model The BCSM is a high level model of call processing for basic call control. Bearer service A bearer service in ISDN consists of the lower three layers of the OSI Reference Model. A bearer service provides the means to convey information between users. Benchmark Systematic comparisons between different units. (Systematiska jämförelser mellan olika enheter.) BGW Billing GateWay BHCA Busy Hour Call Attempt BIB Backward Indicator Bit (SS7 term) The BIB is a bit in an SU which is used in error control. It is toggled when requesting retransmission of an SU which has been received incorrectly. Also see SU, MTP. BIOS Basic Input Output System BLA BLocking Acknowledge (SS7 term) A BLA message is sent to acknowledge receipt of a BLO message. BLO BLOcking (SS7 term) A BLO message is sent by an exchange if it detects a fault in a circuit, this renders the faulty circuit unavailable for further traffic. Bluetooth A radio technique developed at Ericsson since 1996. Today Ericsson cooperates with other companies in the development of Bluetooth. The technique is built up around a data chip which makes it possible to "thread- lessly" transfer data between e.g. a mobile phone and a PC. The range for this is some ten meters. BLT Boot Load Table (TelORB term) BSC Base Station Controller (IN term) A cellular network element that was introduced by GSM. The BSC administers the cells and their radio channels in GSM. The BSC is responsible for the hand over operations of the calls as well as for controlling the power signals between the BTSs and mobile station, thus relieving the switching center of several tasks. The BSS and the Ericsson Base Station System comprises the BSC and the BTS in GSM and CME 20. The BSS connects the MS to the SS. LAPD is a data link protocol used for signalling between the BSC and the BTS. This is known as the A-bis interface. BSN Backward Sequence Number (SS7 term) The BSN is a field in an SU which is used in error control. It contains the sequence number of a correctly received SU which is being acknowledged. Also see SU, MTP. BSS Base Station System (IN term) A GSM device charged with managing radio frequency resources and radio frequency transmission for a group of BTSs. The BSS connects the MS to the SS. BSS components include the BTS and the BSC. (The BSS and the Ericsson Base Station System comprises the BSC and the BTS in GSM and CME 20.) The A-interface is the interface between the MSC and the BSS. Also see GSM, A-interface, BTS, BSC. BSSAP Base Station System Application Part (SS7 term) The BSSAP is the SS7 application part used in GSM for signalling between the MSC, the BSC and the MS. BSSAP is a protocol which has been especially developed for the A-interface in GSM. The A-interface is the interface between the MSC and the BSS. The A-interface is realized over several PCM digital transmission systems containing both speech/data and signalling channels. BSSAP is divided into 2 sub-parts: - Direct Transfer Application Part (DTAP): See DTAP. - Base Station System Management Application Part (BSSMAP): See BSSMAP. Also see GSM, A-interface, LAPD. BSSMAP Base Station System Management Application Part (SS7 term) The BSSMAP is the part of BSSAP which deals with operations such as resource management, handover control and ciphering control. BSSMAP is used to send messages between the MSC and the BSS that are related to: - the MS, e.g. handover control - a particular cell within the BSS - the whole BSS The BSSMAP uses both connection-oriented and connectionless signalling services of NSP. In connection-oriented mode, it is used to support procedures including handover, assignment procedures and Initial MS message handling. In connectionless mode, it is used to support procedures such as blocking a trunk line, reset (restart), and paging an MS. There are some messages which are meant to be sent transparently between the MSC and the MS, but to which the BSC adds information. These messages are called Initial MS messages. Initial MS messages are used for: - loaction updating request - paging response - IMSI detach - CM service request When an Initial MS message is received in the BSC (from the MS), the BSC analyses parts of it and attaches a Cell Global Identity (CGI) to it and sends it to the MSC in a BSSMAP message called "Complete Layer 3 Information". Also see GSM, BSSAP, Initial MS message. BTS Base Transceiver Station (IN term) A GSM device used to transmit radio frequency over the air interface. In digital cellular networks such as GSM, the BSS consists of the BSC and the BTS. The BTS handles the actual radio transmission to and from MSs. LAPD is a data link protocol used for signalling between the BSC and the BTS. This is known as the A-bis interface. LAPDm is an SS7 protocol which facilitates the transport of DTAP and Initial MS messages between the BTS and the MS, i.e. LAPDm is the protocol used to exchange messages between the BTS and the MS. This is known as the Air-interface, or the Um-interface. Buffer In SS7, there are two types of buffer used to store SUs. These are the transmission buffers which hold SUs not yet transmitted and the retransmission buffers which hold SUs transmitted but not yet positively acknowledged. |
| C | Top of Glossary |
C7 Common Channel Signalling System Number 7 or CCITT
signalling system no. 7
C7 signalling is a signalling system used for high speed
control between exchanges. It can control the set-up,
supervision and clearing of voice and data calls.
Because of its comprehensive facilities it is used for
inter-exchange signalling in ISDN, PSTN, PLMN and IN.
C7 was defined by the ITU-T (formerly CCITT) as an
internationally standardised, general purpose common
channel signalling system.
C7 can pass information efficiently in both directions,
carry more information than conventional signalling
methods, operate at high speed to minimize call set-up
and disconnect times, reliably recognize and recover
from transmission errors.
C7 signalling is the standard for connecting SCPs and
SSPs.
See SS7.
Capsule Capsule and process are the same thing in C++, but not
in Java.
CAS Customer Administration System (IN term)
CAS Channel Associated Signalling (SS7 term)
CAS is a signalling system in which a signalling path
(channel) is directly associated with a particular
speech or data circuit (channel).
Also see SS7, CCS.
------------ ------------
| | <-- Speech/Data/Signalling --> | |
| Exchange A | <-- Speech/Data/Signalling --> | Exchange B |
| | <-- Speech/Data/Signalling --> | |
| | <-- Speech/Data/Signalling --> | |
------------ ------------
CCITT Consultative Committee for International Telephone and Telegraph
(now ITU-T)
Comite Consultatif Internationale de Telegraphique et
Telephonique
An international organization that develops standards
and defines interfaces for telecommunications.
See ITU-T.
CCN Cost Control Node
CCS Common Channel Signalling (SS7 term)
CCS is a signalling system in which a single channel
conveys, by means of labelled messages, signalling
information relating to many speech or data channels.
It can also convey other information such as that used
for network management.
In CCS a signalling channel conveys signalling
information for many speech or data circuits. This
requires the use of labelled messages, where the label
indicates the circuit to which the message refers.
SS7 is a CCS system.
------------ ------------
| | <----- Speech/Data -----> | |
| Exchange A | <----- Speech/Data -----> | Exchange B |
| | <----- Speech/Data -----> | |
| | <----- Signalling ------> | |
------------ ------------
CCS is a type of inter-exchange signalling where the
signalling for a large number of voice channels is
carried on a single common control channel, e.g. SS7.
Also see SS7, CAS, DSS1.
CD Compact Disc
CD-R Compact Disc Recordable
Only possible to record once.
CD-RW Compact Disc Rewriteable
Possible to record several times.
CDM Collaborative Data Management (Ericsson term)
Both Corporate and DCND have decided to roll out CDM as
the document management system for the R&D organizations
(at DCND the decision was made on PMTC on September 9th
2003).
CDM is introduced for handling of both reference
notation documents (office documentation) and
registration notation (projects and products).
Cello Cello is the base station for the third-generation
cellular systems, UMTS. (Ericsson term)
Also see CPP.
CGB Circuit Group Blocking (SS7 term)
A CGB message is sent when one exchange wants to notify
another that a group of circuits is no longer available
for normal traffic handling.
CGBA Circuit Group Blocking Acknowledge (SS7 term)
A CGBA message is sent in response to a CGB message to
indicate that a group of circuits has been blocked.
CHA Component Handling (SS7 term)
CHA is one part of the CSL in the TCAP. The other part
is DHA.
CHA maps operation invocations and replies from TC-users
into components and correlates operations and replies.
The CHA primitives are (between TC-user and CSL):
- Invoke operations (TC-invoke)
- Report the success of operations (TC-Result-L,
TC-Result-NL)
- Report the failure of operations (TC-U-Error)
- Indicate rejection of a component (TC-R-Reject,
TC-L-Reject, TC-U-Reject)
- Cancel operation invocations (TC-L-Cancel,
TC-U-Cancel)
Also see CSL, DHA, Primitives.
Changeback SS7 term.
See MTP, STM.
Changeover SS7 term.
See MTP, STM.
CIC Circuit Identification Code (SS7 term)
The CIC is that part of the label in a signalling
message which identifies uniquely a telephony circuit
between a given destination and originating point.
Also see SU, TUP.
CIF Common Integration Framework
An Ericsson framework based on technologies such as Java
and CORBA, which is often talked about as a vital
component in all O&M developments.
Circuit
related
signalling An SS7 term for signalling associated with the setting
up, release or maintenance of a particular circuit.
Also see SS7, SCCP, Non-circuit related signalling.
CK ChecKsum (SS7 term)
CK is a field in an SU. It is used to check the SU for
errors occurring in transmission.
Also see SU, MTP.
ClearDDTS Clear Distributed Defect Tracking System
A distributed trouble report/errand handling system
which is used for TelORB trouble reporting since
December 15, 2000.
TR status - list of 11 different states:
S=Submit Pseudo-state (start)
N=New Newly arrived trouble reports
F=Forwarded Report that shall be transferred to
another project
P=Postponed Report that shall be processed at some
later time
A=Assigned Report being worked on (by an appointed
person)
R=Resolved Report is solved, but not fully tested
T=Testable Report is assigned for testing (by an
appointed person)
V=Verified Report is duly tested with an approved
result
C=Closed Report needs no more processing - solved
and finished
D=Duplicate Status assigned to a report that is a
duplicate of an existing report
X=Cancelled Status given to a report that for some
reason one wants to recall or not spend
any more effort on
I=Incomplete Report which lacks necessary information
for the resolving of the report
CLIP Calling Line Identification Presentation (SS7 term)
A telephony service.
Cluster A cluster is a type of parallel or distributed system
that consists of a collection of interconnected whole
computers used as a single, unified computing resource.
"Whole computer" is meant to indicate a normal, whole
computer system that can be used on its own:
processor(s), memory, IO, OS, software subsystems,
applications.
(Greg Pfister of IBM's Advanced Technology &
Architechture, Server Design Division)
CM Connection Management (SS7 term)
CM messages are sent between the MSC and the MS in
mobile networks.
Functions of the CM are:
- Call Control (CC) and call related supplementary
services management, e.g. user-to-user signalling.
- Short Message Service (SMS).
- Non call related supplementary services (SS), e.g.
registration of call forwarding on no reply.
Also see DTAP, MM, SMS.
CM Configuration Management (Ericsson term)
CMISE Common Management Information Services Element
C-number The C-number is the number of the subscriber to whom the
call is routed (e.g. freephone call).
Component SS7 term. Components are requests sent between TC-users
(via TCAP) (in different nodes) to perform actions
(operations) at the distant end, or the replies to such
requests.
Also see CSL.
Congestion In SS7, congestion may occur on a Signalling Link (SL)
or Signalling Route when that link or route cannot
process any more signalling messages due to the volume
of the traffic.
Connectionless
service One of the two service types supported by OSI.
In a connectionless service, data is transferred from
one point in the network to another without setting up
a connection. Connection is once off between users.
There are no connection establishment, data transfer and
release phases. Each piece of user data, along with the
information needed to route it, is sent separately
through the network. In the connectionless service, data
blocks are referred to as datagrams.
The connectionless service is typically used for the
transfer of small amounts of real time critical data,
e.g. signalling data for the mobile radio network to
transfer requests for mobile subscriber information
within the network.
The SLCL is the SCCP function block which controls the
connectionless functions.
The main characteristics of connectionless services are:
- Flow of information is one way.
- Both routing information and data are transmitted.
- No connection is established.
- Each piece of data is routed independently.
- Received data is not acknowledged.
Connectionless service is like a letter sent by post,
where:
- the full destination address is used
- each letter is routed independently of all other
letters
- the sequence of arrival of letters is not guaranteed
- no logical connection exists between the two users
- the service is a "send and pray" one where there is no
acknowledgement of the data sent and no recovery
process
Examples of users of the SCCP connectionless service:
- Application Parts (APs) interfacing with SCCP via TC.
- SCCP management messages.
Also see Connection-oriented service, Protocol class,
OSI, SCCP, SCLC, UDT.
Connection-
oriented
service One of the two service types supported by OSI.
In a connection-oriented service, firstly a connection
is established. Then data is transferred on that
connection. Finally, the connection is released.
In a connection-oriented service, data is sent in
sequence and received data is acknowledged.
A connection-oriented service is like a telephone call
where a connection is established, the subscribers
speak and the connection is released.
The SCOC is the SCCP function block which controls the
connection-oriented functions.
The main characteristics of connection-oriented services
are:
- A two-way exchange of information.
- The data is sent in sequence.
- Received data is acknowledged.
A signalling connection between nodes may be divided
into a number of connection sections. A connection is
identified by a reference number which uniquely
identifies it within the SCCP. In the connection-
oriented service, the signalling connection can be
either temporary or permanent.
A connection-oriented service is typically used for the
unlimited transfer of large amounts of data which are
not time critical, e.g. the downloading of data between
a bank's main computer and the branches of the bank.
Some additional connection-oriented services include:
- Reset: This reinitializes a signalling connection if
required.
- Notice: This indicates failure and degradation of
services.
Also see Connectionless service, Protocol class, OSI,
SCCP, SCOC, SCLC, UDT.
CORBA Common Object Request Broker Architecture
An architecture which allows interoperability between
services that are implemented in different programming
languages, and on different processor platforms. Also,
it introduces a specification language, IDL, to specify
SW interfaces. CORBA makes it possible to develop
services in open programming languages such as e.g.
Java and C++, and allows these to execute on different
processor platforms.
COS Common Object Services
CPP Cello Packet Platform
CPP will primarily be used in nodes residing in UMTS
Terrestrial Radio Access Network (UTRAN) and in the
"connectivity layer" of the new network architecture
promoted by Ericsson and other leading vendors.
Also see Cello.
CPU Central Processor Unit
The part of the computer that manipulates data and
processes instructions coming from SW or a human
operator.
CR Change Request (Ericsson term)
CRC Checksum Redundancy Check
CS Capability Set (IN term)
The main stream of IN standardization is carried out by
the ITU-T, in the definition of CSs.
CS1 Capability Set 1 (IN term)
The initial realization of the ITU-T Intelligent Network
recommendations.
CSS Cellular Subscriber Station (IN term)
CSL Component Sub-Layer (SS7 term)
The CSL is one of the two parts of the TCAP. The other
part of TCAP is TSL.
The CSL provides TC-users with the facility to send and
receive components.
The CSL maps requests from TC-users into components and
passes them to the TSL.
The CSL provides the TC-user with the capabilities to
invoke remote operations and to receive replies, i.e.
the function of the CSL is to provide the TC-users with
the facility to send and receive components.
Components are requests sent between TC-users (via TCAP)
(in different nodes) to perform actions (operations) at
the distant end, or the replies to such requests.
The services provided by the CSL to the TC-users are:
- the ability to handle components
- support for two types of dialogue (structured and
unstructured)
- facility to correlate operations and replies
- an error handling service
The CSL uses 2 functions to provide these services to
the TC-user, namely:
- CHA (Component Handling)
- DHA (Dialogue Handling)
The CSL deals with the individual components that can be
invoked by the TC-user. When the TC-user invokes an
operation, it passes the dependent parameters to the
CSL (in own node). The CSL receives these requests from
the TC-user, maps them into one of 5 component types and
passes them in primitives to the TSL.
5 types of components can be sent between peer CSLs (in
different nodes) to invoke operations and receive
replies. The 5 component types are:
- Invoke
- Return result (last)
- Return result (not last)
- Return error
- Reject
Several components exchanged between TC-users (in
different nodes) constitute a Dialogue.
There are two kinds of dialogue facilities provided by
the CSL, namely:
- Unstructured: In an unstructured dialogue, TC-users
send components that do not expect
replies. No explicit association is formed
between TC-users. These components are
sent by the TSL in unidirectional
messages. If errors occur, these are
reported in separate unidirectional
message.
- Structured: In a structured dialogue, an explicit
association exists between TC-users. The
TC-user indicates the beginning,
continuation and the end of the dialogue.
The dialogue can be ended by sending an
end message, oganizing a prearranged
ending or aborting the transaction.
Replies to an operation may consist of one or more
components. The last component of a reply will be
either:
- Return result, indicating success.
- Return error, indicating operation failure.
- Reject, indicating syntax error.
The CSL supports 4 classes of operation:
- Class 1, both success and failure are reported.
An example is a request from a remote
database for translation of a freephone
number. Success or failure are both reported
to the TC-user. Under normal circumstances,
the time-out never matures. If it does, then
an error is assumed and the TC-user is
informed.
- Class 2, only failure is reported.
An example is the performing of a routine
test, where a reply is returned only if there
has been an error at the remote end. If the
the time-out expires and no reply has been
received, the TC-user is informed of a
successful outcome for the operation.
- Class 3, only success is reported.
An example is the performing of a routine
test where a reply is returned only if the
operation is successful. If the time-out
expires,and no reply has been received, the
TC-user is informed that the operation has
failed.
- Class 4, neither success nor failure are reported.
An example is where a node sends a warning
to other nodes and doesn't expect a reply. In
this case, no result is returned.
The CSL runs a time-out for each class of operation.
Also see TCAP, TSL, CHA, DHA, TC.
CUG Closed User Group (SS7 term)
A telephony service.
A CUG is a group of customers with special access
facilities within the telecommunications network.
Also see TUP.
CVS Concurrent Versions System
CVS is a front end to the revision control system, which
extends the notion of revision control from a collection
of files in a single directory to a hierarchical
collection of directories consisting of revision
controlled files. These directories and files can be
combined together to form a software release.
CVS provides the functions necessary to manage these
software releases and to control the concurrent editing
of source files among multiple software developers.
CVS keeps a single copy of the master sources. This copy
is called the source "repository" which contains all the
information to permit extracting previous software
releases at any time, based on either a symbolic
revision tag, or a date in the past.
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| D | Top of Glossary |
D-AMPS Digital Advanced Mobile Phone Service
Data Link
Layer The Data Link Layer (layer 2 of the OSI model) is an
essential error-free point-to-point circuit between
networks layers. The layer contains resources for error
detection, error correction, flow control and
retransmission.
The function of this layer is to provide reliable
transfer of data. This includes error detection and
correction, flow control and retransmission.
Also see OSI.
Datagram Datagram is a form of packet switching where each packet is
treated separately. Packets from the same data
connection may take different routes through the
network.
Also see Connectionless service.
DBMS DataBase Management System
DBN Database (for AXE-N)
What does the N in DBN mean? The N is a relic from the
past, i.e. the project AXE-N, where the N probably means
"New", as in the new AXE, whereas DBN can mean the new
database (for AXE-N).
D-channel
signalling The D-channel is the channel used primarily for
signalling information. It may also be used for some
data transmission. The D-channel is 16 kb/s for Basic
Access and 64 kb/s for Primary Access.
DCP Dicos Control Processor (TelORB term)
Default router A default router is used when a host does not recognize
an IP package. In this case the host will send the IP
package to the default router which will take care of
the IP package. The IP address of the default router is
specified in the file /etc/defaultrouter, which is
located on the IO processors (e.g. 134.138.184.1).
Delimitation In SS7, an SU delimitation is one of the functions
defined by level 2 of the MTP. A Flag (F) containing a
unique bit pattern '01111110' is inserted at the
beginning and the end of an SU in order to delimit it.
Also see MTP, SP, SU.
DELOS DEclaration Language for DICOS (TelORB term)
A TelORB specific application specification language.
DELOS specifications are compiled into C++ and Java stub
and skeleton files that the designer completes.
Delux The DELOS compiler (TelORB term)
DHA Dialogue Handling (SS7 term)
DHA is one part of the CSL in the TCAP. The other part
is CHA.
DHA handles the dialogue between two TC-users, i.e. it
provides the facility to exchange successive components
in a dialugue.
The DHA primitives (between TC-user and CSL (DHA)) are
issued to initiate:
- an unstructured dialogue (TC-UNI)
- a structured dialogue (TC-Begin, TC-Continue, TC-End)
The DHA primitives are also used to handle abnormal
situations (TC-U-Abort, TC-P-Abort).
Also see CSL, CHA, Dialogue, Primitives.
DHCP Dynamic Host Configuration Protocol
DHCP provides two IP addresses for each of the TelORB
processors in the TelORB system. DHCP also transfers
static data to the TelORB operating system, such as IP
addresses of different hosts, netmask-, broadcast-,
router-addresses, port numbers where to find boot PROMs,
etc.
dhcptab A file located at /var/dhcp/ on the IO processors.
It is used by the DHCP function when the TelORB
processors are starting up, where the information in
this file is sent to each of the TelORB processors.
Dialogue An SS7 term for an association established between two
TC-users (in different nodes) exchanging data.
Also see TC, TCAP, CSL, DHA.
DICOS DIstributed Communications Operating System (TelORB term)
Same as TelORB, but TelORB is today more than just the
operating system. Runtime software upgrades and fault-
tolerance by redundancy is handled by DICOS.
DID Database IDentifier (TelORB term)
DIOP DICOS Inter-ORB Protocol (TelORB term)
Makes it possible to access objects even if they are
moved to other TelORB processors.
DIP stack Distributed Internet Protocol stack (TelORB term)
The DIP stack was introduced in TelORB in TelORB release
R14. It helps out in the VIP addressing of a TelORB
system.
Also see VIP, RIP.
Discrimination In SS7, discrimination is one of the message
handling functions of level 3 of the MTP. The
discrimination function passes on a message to the
distribution function if the message belongs to the
SP to which it has been sent. If the message is
destined for another SP it is transferred to the
routing function.
Also see MTP.
Distribution TelORB term.
A distribution is made from the testbed, and is in the
structure of the eventual product release.
Distribution In SS7, distribution is one of the message
handling functions of level 3 of the MTP. The
distribution function examines the Service Indicator
(SI) to determine the destination of the message,
i.e. to which UP the message will be sent.
Also see MTP.
DNS Domain Name System (TCP/IP base application)
A function where information about work station
addresses and names are stored in a central place (DNS
server) where all workstations can access them.
DNS is a distributed catalogue service and is used for:
- Connections to computers with hostnames: DNS maps
a hostname (domain name) against an IP address, e.g.
telorb.guidelines.ericsson.se --> 194.52.54.36.
- Reverse look-up: E.g. 194.52.54.36 -->
telorb.guidelines.ericsson.se.
- Delivery of electronic mail: DNS maps the mailaddress
to host, e.g. ericsson.se --> 1 mail.ericsson.se
--> 2 sunic.sunet.se
(DNS = "Telefonkatalog")
DOA Database Object Agent (TelORB term)
DOI tests Database Object Interface tests
Testing the database interface by use of the TestManager
which is created by uabseri.
DOS Disk Operating System
DOS is the SW that organizes how a computer reads,
writes, and reacts with its disk and talks to its
various input/output devices.
DP Destination Point (SS7 term)
An SS7 signalling message is generated at one SP and
sent to another. The SPs are called the OP and DP,
respectively.
DPC Destination Point Code (SS7 term)
The DPC is that part of the label in a signalling
message which uniquely identifies the SP to which the
message is finally addressed.
The originating and destination SPs are identified by
an OPC and a DPC, e.g. OPC is 300 and DPC is 400.
The OPC and DPC are contained in a part of the SS7
labelled message called the Routing Label.
Also see MTP, SP, SS7, STM, SU, TFP, TUP.
DPI Dicos Programming Interface (TelORB term)
DPNSS Digital Private Network Signalling System
DRAM Dynamic Random Access Memory
The readable/writable memory used to store data in the
computer.
Driver A device driver is a software program which makes a
hardware device work.
DSL Digital Subscriber Line
DSS1 Digital Subscriber Signalling System No. 1
DSS1 is a type of CCS between the subscriber terminal
and the local exchange in ISDN.
DST Daylight Saving Time
DT message Data form message (SS7 term)
The user data is packed into DT messages.
The DT message contains:
- NPCI
- NSDU
If the size of the user data is too big to be
transferred within one message, segmentation of the data
over several DT messages is permitted. The more-data
(M-bit) in a DT indicates that the NSDU has been
segmented.
A DT message can be either DT 1 or DT 2.
Also see DT1, DT2, NPCI, NSDU, SCCP.
DT 1 Data form 1 (SS7 term)
DT 1 is a message, in the SCCP, which is sent by either
end of a signalling connection to pass SCCP User data
transparently between two SCCP nodes. It is used during
the data transfer phase in protocol class 2 only.
A connection-oriented class 2 message is called Data
Form 1 (DT1).
Also see SCCP.
DT 2 Data form 2 (SS7 term)
DT 2 is a message, in the SCCP, which is sent by either
end of a signalling connection to pass SCCP User data
transparently between two SCCP nodes and to acknowledge
messages flowing in the other direction. It is used
during the data transfer phase in protocol class 3 only.
A connection-oriented class 3 message is called Data
Form 2 (DT2).
All DT2 messages sent must be acknowledged.
DT2 messages are acknowledged by:
- Sending a Data Acknowledge message to the originating
node.
- Sending a DT2 message to the originating node.
Each DT2 message contains a Send Sequence Number (PS)
and a Receive Sequence Number (PR).
Also see SCCP.
DTAP Direct Transfer Application Part (SS7 term)
DTAP is the SS7 application part used in GSM which deals
with functions such as call control and mobility
management. DTAP messages are transferred between the
MSC and the MS via the BSS.
DTAP is used to send Connection Management (CM) and
Mobility Management (MM) messages between the MSC and
the MS. These messages are sent transparently through
the BSS in connection-oriented mode.
See CM for further info.
LAPDm is an SS7 protocol which facilitates the transport
of DTAP and Initial MS messages between the BTS and the
MS.
Also see BSSAP, LAPDm.
DTMF Dual Tone Multi-Frequency
A DTMF phone sends audiable signals rather than the
pulses which are used in older phones.
DTMF is a term describing Touchtone, or Push button,
dialling. By touching a button on a push button pad, it
makes a tone, actually a combination of two tones, one
high frequency and one low frequency.
Certain IN services, such as bank account enquiries and
credit card verifications, allow users to enter number
via a DTMF phone, and to make simple selections by
pressing digits when prompted.
DU Distribution Unit (TelORB term)
A DU is a group of processes and/or (belonging)
database persistent objects. The grouping is performed
for distribution reasons.
------- --------
| IDP | | Zone |
------- --------
/ \ |
------ ------ --------
| LM | | LM | | Pool |
------ ------ \ ------ / --------
/ \ | DU | |
------ ------- ------ -------------
| OU | | SWI | | Processor |
------ ------- -------------
Also see DUT.
DUCK Dicos UNIX Communications Kernel (TelORB term)
Phased out in TelORB release R14.
DUG Distribution Unit Group (TelORB term)
A DUG is a group of DUs and it handles the DU processes.
A DUG starts and stops processes.
A DUG is supervised by the CMA and the CMA starts all
DUGs.
DUT Distribution Unit Type (TelORB term)
DUTs are specified in DELOS by the designers.
E.g. a process in an LM and the process' belonging
database object are distributed as a DUT and are then
allocated to a distribution pool.
A DUT is given a name and a distribution limit value,
where a higher value implies a more even distribution of
the DUs that have the DUT characteristics. E.g.
distribution limit 5 means 5 DUs.
A DUT is allocated to a Distribution Pool (Processor
Pools) in a configuration file by the designer.
Typically, 1-3 pools are used per application. TelORB
uses 4 pools.
A site specific config file then allocates TelORB
processors to different pools.
Distribution limit = 12 in a zone with 3 TelORB
processors will e.g. distribute the DUs as follows, if
all TelORB processors are allocated to the pool:
Processor 1: DUs 4-5, 10-11 (Primary replicas)
Processor 2: DUs 0-1, 6-7 (Primary replicas)
Processor 3: DUs 2-3, 8-9 (Primary replicas)
Processor 1: DUs 2-3, 6-7 (Redundancy replicas)
Processor 2: DUs 4-5, 8-9 (Redundancy replicas)
Processor 3: DUs 0-1, 10-11 (Redundancy replicas)
Also see DU.
DVD Digital Versatile Disc
|
| E | Top of Glossary |
EDGE Enhanced Data services for Global Evolution
EGP Exterior Gateway Protocol
Also see IGP.
EHDE Ericsson Hard Disk Encryption
Protects your data against unauthorized access and in
the event your computer is stolen. EHDE is easy to
install and to handle.
EIR Equipment Identity Register
One of the SS components.
The EIR is a database in the GSM network. It contains
information on mobile equipment and is used for
equipment identity checking.
Also see SS, GSM.
EMC Electro-Magnetic Compatibility
Emulate Pretend to be e.g. a terminal which acts in a certain
way.
End-to-end
signalling End-to-end signalling is the sending of information
directly between the end exchanges of a call. This
information is relevant only to the end exchanges of a
call and is not interpreted at the intermediate
exchanges.
End-to-end signalling is when signalling is transmitted
from one network to another, through intermediate nodes
which do not analyze the information they are passing
on.
ep Elof Project (TelORB term)
Some of the TelORB "tools", e.g. epct, epbuild and
epconfig, start with the letters 'ep'. This is because
the day the TelORB project was started (AXE-N), Elof had
his name-day ("namnsdag" in Swedish) (June 30).
Since nobody could come up with a good name for the
started project, Elof, was used and thus the project
name "Elof Project" came to influence the TelORB command
names.
Erlang A programming language developed at Ericsson, based on
standard platforms (UNIX, Linux, Windows, VxWorks) for
fault-tolerant telecom applications. It is a functional
language with asynchronous message passing and a small
syntax, making it fast to learn and quick to write
powerful applications.
ES Ethernet Switch
ESB Ethernet Switch Board
EST Early System Test (TelORB term)
Early test phase performed by UAB/S/DV.
EthA Ethernet Switch A (TelORB term)
Ethernet Switch 0.
EthB Ethernet Switch B (TelORB term)
Ethernet Switch 1.
Ethernet The network connection for the Transparent Network.
ETSI European Telecommunications Standards Institute
This institute is the European counterpart to ANSI. Its
task is to pave the way for telecommunications
integration in the European community as part of the
single European market program. Setting standards for
GSM is included in their work.
Also see ANSI.
EUT Equipment Under Test (Pilot term)
|
| F | Top of Glossary |
FIB Forward Indicator Bit (SS7 term) The FIB is a bit in an SU which is toggled for an SU being retransmitted. It is used for error control. Also see SU, MTP. FISU Fill In Signal Unit (SS7 term) FISU is one of the 3 SU types. FISUs are sent from level 2 of the MTP and their function is to maintain link continuity and to acknowledge any received MSUs when no other SU types are being sent. Also see SU, MTP. Flag (F) In SS7, the flag is a field in an SU. It consists of a unique bit pattern which is used to delimit the SU. Also see SU, MTP. Freephone Example of an IN service. In the freephone service, the charges for the call are paid for by the person receiving the call, e.g. a company such as a bank, travel agent or insurance company, i.e. the freephone service subscriber. Freephone services have a special prefix number, e.g. 800, which indicates to the PSTN local exchange that it is an IN service call. Freephone uses non-circuit related signalling (see SS7). FSN Forward Sequence Number (SS7 term) The FSN is a field in an SU. It contains the number of the SU being transmitted and is used for error control. Also see SU, MTP. FTP File Transfer Protocol (TCP/IP base application) |
| G | Top of Glossary |
Gateway The tasks of a gateway is to convert "sound" (byte stream, package "train"). The procedure of a gateway is to: - Capture X milliseconds of "sound". - Compress (not always). - Put into package. - Send. Extra gateway features may be silence supression and echo cancelling. GEM Generic Ericsson Magazine (Ericsson term) TelORB HW cabinet introduced in TelORB R14. GEM is the preferred magazine infrastructure for TelORB, as well as for AXE and other system platforms. Geographical Network Redundancy TelORB term for two TelORB zones which cooperate to be redundant for each other. Updtaes of the TelORB databases are transferred between the zones using TCP/IP connections directly between TelORB processors in the different zones. Also see PNR. GGSN Gateway GPRS Service Node (IN term) GIOP General Inter-ORB Protocol GIX Global Internet Exchange GMSC Gateway Mobile Switching Centre (IN term) (or Gateway Mobile Services Switching Centre) The GMSC acts as a gateway for incoming calls to the GSM network. A GMSC provides interconnections to other networks such as the PSTN, ISDN, IN and mobile networks. Also see GSM, MSC. GPRS General Packet Radio Service (IN term) GPRS is one of the key technologies that will expand the bandwidth capabilities of wireless networks, and support high-speed services such as fast Internet access, real-time multimedia and video communications. GPRS is a new way of transferring data in the GSM network. With a GPRS phone you can be constantly connected, which makes access times shorter to e.g. WAP services. You do not pay per minute, just for the amount of data that is transferred, since the network is only used during transfers. GSM Global System for Mobile communications (IN term) GSM is the ETSI standard for digital cellular telephony found in Europe and Japan. A large number of countries world-wide have committed themselves to GSM. A GSM network comprises of the following components: - Mobile Station (MS): See MS. - Base Station System (BSS): See BSS. - Switching System (SS): See SS. ------ ------- ------ | SS |---| BSS |---| MS | ------ ------- ------ SS components: MSC, HLR, VLR, EIR, AUC. BSS consists of BTS and BSC. MS consists of ME and SIM. This graphic illustrates the SS7 protocols used in GSM: ------- MAP ------- -- | VLR | <---------> | HLR | | ------- ------- | ^ ^ | MAP | ---------- | MAP | |---> | _ _ | <---| | | \/ | |-- SS | /\ | MSC | | - - | | |--------| | |---> ||BSSAP || | | |--------| | | ---------- | | ^ ^ -- BSSMAP | | | DTAP \/ | | -- ------------------- | | -------- | | | BSS |BSSAP | | | | -------- | | ------------------- | ^ ^ | | | | | |-- BSS | | \/ | ------- | | BSC | | ------- | LAPD | (A-bis interface) | ------- | | BTS | | ------- | LAPDm /_ /_ (Air interface) -- / / (Um interface) -- |-- MS Mobile Subscriber | -- In the GSM network, a number of SS7 UPs and APs are utilized for both inter-exchange and subscriber signalling. The following UPs are used in GSM: - Telephony User Part (TUP): This UP is that part of a telephone exchange which uses the SS7 signalling system to control telephone calls and circuits. See TUP for further info. - ISDN User Part (ISUP): This is the UP of an ISDN exchange which generates messages to control ISDN calls and circuits. See ISUP for further info. The following APs are used in GSM: - Mobile Application Part (MAP): See MAP. - Base Station System Application Part (BSSAP) - Direct Transfer Application Part (DTAP) - Base Station System Management Application Part (BSSMAP) In addition, there are 2 other protocols used: - LAPD, a data link protocol, used for signalling between the BSC and the BTS. - LAPDm, an SS7 protocol, facilitates the transport of DTAP and Initial MS messages between the BTS and the MS. Description of a call to a Mobile Station (MS): In a mobile network, a call to a subscriber is more complicated than is the case for a PSTN subscriber. First the subscriber must be located. The following example outlines the steps taken to establish a call from a PSTN subscriber to a mobile subscriber. The PSTN subscriber dials the Mobile Station ISDN (MSISDN) number. This is sent in an Initial Address Message (IAM) from the PSTN to the Gateway Mobile Services Switching Centre (GMSC). The GMSC analyses the MSISDN to acertain which HLR the MS is registered in. (The HLR is a database containing data about the MS, including the last recorded location.) The GMSC requests the location of the MS from the HLR by invoking a MAP operation . send routing information - in the HLR. The MSISDN is included in this operation. A TCAP message using the connectionless services of the SCCP is sent from the GMSC to the HLR. MAP in the GMSC sends a TCAP message to MAP in the HLR using the services of the NSP. The HLR translates the MSISDN into an International Mobile Subscriber Identity (IMSI) which contains the address of the MSC/VLR in whose area the MS is currently located. It then requests a Mobile Station Roaming Number (MSRN) from the MSC/VLR by invoking a MAP operation - provide roaming number - in the MSC/VLR. The IMSI of the MS is included in the message. As before, a TCAP message using the connectionless services of the SCCP is sent from the HLR to the MSC/VLR. MAP in the HLR sends a TCAP message to MAP in the MSC/VLR using the services of the NSP. The MSC/VLR checks to see if the MS is attached and, if so, allocates an idle MSRN and links it to the IMSI. The MSRN is now returned to the HLR. The HLR receives the MSRN from the MSC/VLR and transfers it to the GMSC. The GMSC analyses the MSRN and sends an IAM to the appropriate MSC/VLR. When the MSC/VLR receives the IAM containing the MSRN, it analyses the number and recovers the IMSI. (The VLR has a data record for the subscriber which contains the location area of the MS.) The MSC/VLR sends a paging command to the BSC of this location area using the BSSMAP message "Paging". On receipt of this message, the BSC sends a (LAPD) paging command to all BTSs in the location area. A Paging message is then sent using the LAPDm protocol over the air-interface. After switching from a common control channel to a dedicated channel, the MS sends a paging response. The BTS then sends an establish indication, using the LAPD protocol, to the BSC to indicate a paging response. The BSC relays the page response message to the MSC in an SCCP connection-oriented Connection Request (CR) message. For security reasons, an authentication procedure now takes place. DTAP messages are exchanged between the MSC and the MS (which pass transparently through the BSS). For confidentiality over the air-interface, a ciphering sequence takes place. All speech and data are ciphered and all signalling information is protected. After authentication and ciphering have been completed, call set-up and the assignment of a free traffic channel takes place. Conversation can then take place. Also see 3G, MS, BSS, SS, BSC, BTS, TUP, ISUP, MAP, BSSAP, DTAP, BSSMAP, LAPD, LAPDm. GSS Group Switching System GT Global Titles (SS7 term) This is an address, such as customer dialled digits, generated by the SCCP Users. The GT needs to be translated before it can be used for routing in the signalling network. E.g. an ISDN number would be tranlated into a DPC. The translation purpose is performed by the SCCP Routing function. For this purpose the SCCP holds translation tables containing the numbering plans for the available networks. For connection-oriented procedures, the Calling/Called Party Addresses are the origination and destination of the signalling connection. Connection-oriented messages (except for Connection Request (CR)) contain a DPC. CR may contain: - DPC plus SSN or GT or both - GT - GT or SSN For connectionless procedures, the Calling/Called Party Address are the origination and destination of the message. Connectionless messages may contain: - DPC plus SSN or GT or both - GT - GT or SSN Also see SCCP, SCR, SPC, SSN. GUI Graphical User Interface |
| H | Top of Glossary |
HLR Home Location Register (IN term) One of the SS components. In a PLMN, the HLR is a database which contains mobile phone numbers, subscriber data (e.g. what services a subscriber can access) and the position of all mobile phones in service belonging to the HLR in question. Also see SS, GSM. Host Equipment that can send and receive data, e.g. a PC. HSS Home Subscriber Server (IN term) An IP-based server that evolves the HLR combined with an AAA server. It can also be described as a combined HLR and AUC for 3G networks. It stores and manages data about mobile subscribers, such as location information-HLR (Home Location Register) functions. And it provides encryption and verification functions to protect the wireless network from fraudulent use--AUC (Authentication Center) functions. HSSL High Speed Signalling Link HTML HyperText Markup Language Programming language for creation of internet pages. |
| I | Top of Glossary |
I²C Inter-IC Bus
IAM Initial Address Message (SS7 term)
The IAM is an address message in both the TUP and the
ISUP. Information contained in the IAM includes Called
Party Address and Calling Party Category.
Also see SS7, TUP, ISUP, SAM.
IAS Internet Access Server (IN term)
ICMP Internet Control Message Protocol (TCP/IP additional application)
ICMP is mandatory and should be seen as a part of IP.
ICMP handles:
- ping (ICMP Echo)
- Error reporting:
- Destinations cannot be reached.
- Flow control.
- Too many router jumps.
- Routing messages:
- ICMP Redirect
IDL Interface Definition Language
IDP Internal Delivery Package (TelORB term)
A container of LMs.
IE Information Element (SS7 term)
The contents of a TCAP message may consist of a number
IEs.
See TCAP.
IGP Interior Gateway Protocol
Also see EGP.
IIOP Internet Inter-ORB Protocol (Internet InterOperability Protocol)
Part of the CORBA standard. IIOP is also used for
managing the TelORB system.
TelORB supports the IIOP, which is transported over
TCP/IP.
ILR Interworking Location Register (IN term)
IMS IMS - IP Multimedia Subsystem
An international, recognized standard; it specifies
interoperability and roaming; and it provides bearer
control, charging and security. What is more, it is
well integrated with existing voice and data networks,
while adopting many of the key characteristics of the
IT domain. This makes IMS a key enabler for fixed-mobile
convergence and value-based charging.
(White Paper, IMS - IP Multimedia Subsystem October
2004).
IMSC Interworking MSC (IN term)
IMSI International Mobile Subscriber Identity (IN term)
See GSM.
IN Intelligent Network
The term Intelligent Network (IN) was first phrased in
Bellcore (company in U.S.A.) in 1984.
The term IN is used to describe networks that have more
intelligence (stored data and processing) than previous
public switched networks. INs separate the service
functionality from the rest of the system. This allows
the network service provider to modify and introduce new
services independently of the rest of the system.
IN is a network architecture which separates the
switching and service functions of the network. This
makes it possible for new services to be introduced
quickly and with minimum disruption to the existing
network.
IN is a network architecture which is overlaid on the
existing network and can be applied to various types of
telecommunications networks. These telecommunications
networks include PSTN, PSDN, mobile networks, and ISDN
(both narrowband and broadband).
IN has been defined as `a telecommunications network
with service independent capabilities that allows the
service provider to define and competitively provide
new network services'.
`Service independent capabilities' means that the
service functionality is separate from the rest of the
network.
The main goal of IN is to provide a framework so that
the service provider can introduce, control and manage
services more effectively and economically than existing
networks allow.
The basic requirements of INs include the transmission,
switching and signalling of information related to the
services they provide.
The main benefit of IN to the service providers is the
potential to generate increased revenue. Other
benefits of IN to the service providers include choice
of e.g. vendor equipment, customization of services,
flexibility, and speed (fast introductions and
deployments of new services into the market place).
The benefits of IN to the subscribers are choice of
services, suitablity (being offered services which match
their needs), speed (fast introductions and deployments
of new services), access, and revenue (buying services
from the service providers and offering these services
to their own customers).
The main players in the IN market are service providers,
vendors, and subscribers (both service subscribers and
service users).
An IN is made up of an integrated computer and telephony
network management system and a computer-based network
management system.
The main components of an IN are SCP, SSP, STP, SDP, IP,
SMS, SCE and SME. See picture:
|-------------------------------------------|
| IN S |
| == |----------| e |
| | SME | r |
| (SDP)-------( SCP )-------|(SMS, SCE)| v |
| / /\ \ |----------| i |
| / / \ \ c |
| (STP) / \ (STP) e |
| | / \ | / |
| | / \ | S |
| |/ \| w |
| (SSP) (SSP)-------(IP) i |
| | | t |
| | | c |
| | | h |
| | | i |
| | | n |
| | | g |
|--------- | ---------- | ------------------|
| |
(LE) (LE)
(Subscribers) (Subscribers)
Examples of IN services are freephone, premium rate,
televoting, credit card verification, VPN, UAN and UPT.
Prior to deregulation, the four main technical advances
which made the implementation of IN possible were SPC,
digital technology, C7 signalling and database
technology.
The main bodies involved in the standardization of IN
include ITU-T (U.S.A.), ETSI (Europe) and Bellcore
(U.S.A.).
The speed at which SS7 operates is capable of handling
the signalling messages between SSPs and SCPs in IN. The
INAP is the SS7 part which is used for communication
between SSPs and SCPs.
INAP Intelligent Network Application Part (SS7 explanation) (Part of AP)
The INAP is the application part (AP) of an IN node.
It generates messages for IN calls.
The specific signalling requirements for IN are provided
by INAP.
INAP interworks with TC, SCCP and MTP.
Intelligent Network Application Protocol (Explanation found
elsewhere)
INAP is the IN specific protocol developed by ITU-T
which runs over the C7 signalling system.
The INAP is the SS7 part which is used for communication
between SSPs and SCPs.
INF INFormation (SS7 term)
Information message is a message used by interworking
exchanges to request and present information used in the
setting up of a call.
Initial MS
message A protocol between the MSC and the MS. (SS7 term)
There are some messages which are meant to be sent
transparently between the MSC and the MS, but to which
the BSC adds information. These messages are called
Initial MS messages.
Initial MS messages are used for:
- loaction updating request
- paging response
- IMSI detach
- CM service request
When an Initial MS message is received in the BSC (from
the MS), the BSC analyses parts of it and attaches a
Cell Global Identity (CGI) to it and sends it to the MSC
in a BSSMAP message called "Complete Layer 3
Information".
Also see BSSMAP, LAPDm, MS, BTS, Protocol.
INR INformation Request (SS7 term)
An INR message is sent by an exchange to request
information in association with a call.
INS Intelligent Network Server
Inter
exchange
signalling In SS7, this involves signalling between exchanges. It
can be either CAS or CCS.
IO1 IO processor 1 (TelORB term)
IO2 IO processor 2 (TelORB term)
IOR Interoperable Object Reference
A flexible addressing scheme, which makes it possible
to address objects.
An example of an IOR is an address to a TelORB system
from an outside point of view.
IP Internet Protocol
IP Intelligent Peripheral (IN term)
One of the main components of IN.
The IP is an input/output device, capable of playing
recorded announcements and receiving DTMF digits from a
user.
The IP receives requests for specific user interaction
functions, such as the playing of a recorded
announcement, from the SSP.
IPs can also act as voice/fax mail nodes and other
messaging nodes.
The Special Resource Function (SRF), which is usually
located in an IP, interacts with users to perform
functions such as voice mail and voice announcements.
The SRF may also contain logic and processing functions
to send/receive and convert information from users.
IP-BSS Internet Protocol Base Station System
IP-BSS is a system which works as a link between today's
GSM and the future's 3G mobile system.
IPC Inter Process Communication (TelORB term)
TelORB in-house protocol.
Communication interface between TelORB processes
within a TelORB processor or between TelORB processors.
Messages in IPC are byte buffers with the maximum length
of 65408 bytes.
A TelORB zone is internally built around dual ethernets
where all processors have direct contact (i.e. no
routing needed) with all other TelORB processors in the
same zone, and also with two or more IO processors.
Communicatin between TelORB processors uses the IPC
protocol, an in-house protocol layered directly on top
of MAC, while other communication, both between TelORB
processors and IO processors, and between IO processors,
uses IP protocol stacks, UDP/IP and TCP/IP.
In a TelORB system, applications communicate through
dialogues which are specified in Delos. The dialogues
use TelORB IPC as their communication basis. IPC ports
are objects representing endpoints for message
transfers.
A faster interface for direct access is LPC.
I-PIMS Design Process Information Management System (TelORB term)
IPN InterProcessor Network (TelORB term)
IPSI I-PIMS Shell Interface (TelORB term)
Command interface to I-PIMS.
IP telephony The telephones are IP-telephones (LAN phones), i.e.
they are connected to an IP network built on e.g. CATV,
xDSL, radio, etc.
A gateway connects to an existing PSTN network.
The H.323 standars is important.
LANphone -- Internet and/or own IP network -- Gateway --
PSTN/ISDN -- POTS
ISDN Integrated Services Digital Network
A technique to integrate different digital services,
e.g. speech, data, images, etc. in the same network.
The ISDN is a digital switched network providing
64kb/s channels (with some variants) to users. It is
capable of carrying voice, data, electronic documents,
etc. ISDN provides the user with a single physical
interface for all these services.
The ISDN is the international standard for an integrated
services digital switching network. It offers services
such as data, voice, telex and fax over a single network
access.
SS7 is used in ISDN to support the range of teleservices
offered by the ISDN such as voice, fax and data. It is
also used to support supplementary services such as
Calling Line Identification Presentation (CLIP) and
Closed User Groups (CUGs).
ISDN can also provide additional non circuit-related
functionality, e.g. in the user-to-user signalling
services. In the user-to-user signalling, user-to-user
information is passed on the D-channel to the ISUP,
where it is embedded in an ISUP signalling message, e.g.
in the ISDN set-up message Initial Address Message
(IAM). The ISUP message is passed (via the MTP) to the
destination ISUP. There the user-to-user information is
extracted and passed to the B-subscriber. User-to-user
data is transmitted transparently through the network.
It is not analysed at intermediate nodes.
The exchange of messages for user-to-user signalling is
shown below:
A-subscriber ---> ISUP ---> ISUP ---> B-subscriber
------------ ---- ---- ------------
D-channel SS7 D-channel
Set-up IAM Set-up
Also see ANSI.
ISO International Standards Organization
ISO is a standards-making body which defines standards
for a range of products and services, including
computing and communications.
ISP In Service Performance
The total amount of time per year when a system is
actually in service (running). ISP is stated in percent
and corresponds to a downtime, e.g.
- ISP 99.95% gives a downtime of 263 minutes per year
- ISP 99.99% gives a downtime of 47 minutes per year
- ISP 99.999% gives a downtime of 5 minutes per year
ISP Intermediate Services Part (SS7 term) (Part of AP)
The ISP is used by the TCAP where there is a large
amount of data interchange between applications.
ISP and TCAP enable the introduction of interactive
network-wide signalling communication as used in mobile
networks.
APs that use ISP and TCAP are, e.g. MAP and OMAP.
ISP provides services for TCAP.
ISP corresponds to layers 4 to 6 of the OSI model.
It has not been specified or implemented, and is
effectively not present in SS7 implementations.
The TCAP layer directly accesses the service primitives
provided by the SCCP.
Also see TCAP, AP, OMAP.
ISUP ISDN User Part (SS7 term) (Part of UP)
ISUP is a signalling protocol used for inter-exchange
signalling to support the ISDN. It generates the
messages used to control ISDN calls and circuits.
The ISUP is the UP of an ISDN exchange.
ISUP generates messages to control ISDN calls and
circuits.
ISUP caters for ISDN services to users.
ISUP is used to generate messages for setting up calls
and controlling services in the ISDN network.
The basic service supported by the ISUP is the control
of 64 kb/s switched connections for both speech and
data.
The ISUP uses the end-to-end signalling capabilities of
the SCCP for the transfer of non circuit-related
signalling information. The SCCP then interworks with
the MTP. The combination of SCCP and MTP is called the
Network Service Part (NSP).
Also see UP, TUP, SS7, ACM, Answer message, SCCP, MTP,
NSP.
Iterate Scan, look thru.
ITU-T International Telecommunications Union - Telecommunications
(previously CCITT)
The ITU is an organization established to promote
worldwide standards and the development of
interworking telecommunications networks throughout
the world. ITU is subordinate to the United Nations and
ITU-T is the telecommunications standardization sector
of ITU.
|
| J | Top of Glossary |
JAL Jambala Layer (Jambala term) JDK Java Development Kit (Java term) JNI Java Native Interface (Java term) Makes it possible to implement java functions in C and C++. JPEG Joint Photographic Experts Group JWG Jambala WAP Gateway (Jambala term) |
| K | Top of Glossary |
Nothing yet |
| L | Top of Glossary |
Label The label is an SS7 term and is part of the SIF of an MSU. It is used for message routing within the signalling network. It contains 3 subfields: DPC, OPC and SLS. Also see SIF, MTP, SU, SL, SS7, STM, CCS, CIC, DPC, OPC, SLS. LAPD Link Access Procedure on D-channel (SS7 term) LAPD is a data link protocol used for signalling between the BSC and the BTS. This is known as the A-bis interface. Also see GSM. LAPDm Link Access Procedure on D-channel for mobiles (SS7 term) (or Link Access Procedure on D-channel modified) The LAPDm is an SS7 protocol which facilitates the transport of DTAP and Initial MS messages between the BTS and the MS, i.e. LAPDm is the protocol used to exchange messages between the BTS and the MS. This is known as the Air-interface, or the Um-interface. Also see GSM, BSSAP, Initial MS message. Layer enveloping In the OSI model, as data is transferred from layer to layer, each layer adds its own protocol control information and then passes the data on to the next layer. This is called layer enveloping. LE Local Exchange (IN term) LI Length Indicator (SS7 term) The LI is the field in an SU which is used to distinguish between different SU types. It is also used to indicate the length of the Status Field (SF) of an LSSU and the SIF of an MSU. Also see SU. LM Load Module (TelORB term) A file which contains compiled and linked executable code. An LM is the smallest code element. LMD Load Module Distributor (TelORB term) LMR Load Module Receiver (TelORB term) LPC Linked Procedure Call (TelORB term) or Local Procedure Call (TelORB term) LPC is a way for calling code in another LM. By means of the LPC mechanism, a process that executes code in one LM can create and use objects defined in another LM. If an LM is updated, the new version will be used without having to relink (offline) the code that uses it. Also see IPC. LRN Local Reference Number LRNs are used at intermediate nodes to link incoming and outgoing connections. LS Link Set (SS7 term) A number of SLs, between two nodes (SPs, exchanges), are called an LS. An LS consists of a number of SLs between adjacent SPs. The first operation carried out when an LS becomes unavailable because of a fault is a ChangeOver procedure, see STM. If e.g. the LS between STP B and SP D develops a fault, STP B and SP D perform the changeover operation. STP B sets destination SP D as unavailable via LS BD, so STP B will not attempt to send any SUs to SP D over this LS. STP B transfers traffic destined for SP D via other available S(T)Ps and this is also the case for SU transfers from SP D to STP B. The Transfer Prohibited(TFP) message informs other adjacent S(T)Ps that the signalling route to destination SP D is unavailable through STP B. Also see STM, TFP, MTP, SL, SP, SRM, SS7, SU. LSSU Link Status Signal Unit (SS7 term) LSSU is one of the 3 SU types. LSSUs are sent from level 2 of the MTP to indicate a change in status of a signalling link (SL). Also see SU, MTP, SL, LI. |
| M | Top of Glossary |
MAC Media Access Controller MAG Transformers for adaptation to balanced Ethernet. MAP Mobile Application Part (SS7 term) (Part of AP) The MAP is that part of the SS7 node which is used to generate messages regarding the management of the mobile telephony network. The MAP is a protocol especially designed to meet GSM requirements. In the OSI model, MAP, like the other APs, resides at layer 7 (layers 4 to 6 are transparent to MAP). The MAP is used for communication between the MSC and the HLRs and VLRs. MAP uses TCAP combined with the SCCP connectionless service to invoke operations and send replies between nodes within the SS. APs that use ISP and TCAP are, e.g. MAP and OMAP. The MAP is used for the management of the mobile telephone network. The MAP is used for non-circuit related signalling such as the sending of information between the MSC and the Home and Visitor Location Registers (HLRs and VLRs). This database information is used, e.g. for roaming and rerouting. An example of the use of MAP in the SS7 network might be updating a database with subscriber location information. MAP interworks with TC, SCCP and MTP. MAP is divided into 5 Application Entities (AEs): - MAP-MSC (AE) - MAP-VLR (AE) - MAP-HLR (AE) - MAP-EIR (AE) - MAP-AUC (AE) A SubSystem Number (SSN) is assigned to each of these AEs so that the SCCP can address an AE directly. Each AE consists of a number of Application Service Elements (ASEs). An ASE function consists of one or several operations to perform tasks between MAP entities, e.g. location updating between a VLR and an HLR. These ASEs are grouped into: - specific ASEs, those used in a specific MAP AE only. - common ASEs, those used in all MAP AEs. E.g. TCAP is a common ASE which resides in all MAP AEs. MAP is widely used for a variety of operations in GSM, including: - location updating, for messages from the VLR to the HLR. - inserting subscriber data, for messages from the HLR to the VLR. - location cancellation, for messages from the HLR to the VLR. Also see GSM, OMAP, AE, ASE, TCAP, SCCP. MDP Master Data Partition (TelORB term) An MDP is the data part of a DU, keyed or non-keyed. "Synched mdp" which is shown in the TelORB processor console during e.g. reload indicates that the TelORB processor is checking that its database objects and its replicas have the same contents. ME Mobile Equipment (IN term) A mobile (cellular) phone. MGC Media Gateway Controller (IN term) MGCF Media Gateway Controller Function A server. MGW Media GateWay (IN term) MI Managed Item (TelORB term) MI type Managed Item type (TelORB term) The most basic MI types are LM, IDP, OU, SCC and SWI. LMs include OUs which provide SWIs and use OUs that are provided by other LMs. An SCC also provides SWI(s). MIA Manual Intervention Allowed MIB Management Information Base (TCP/IP additional application) MII Media Independent Interface (for Ethernet) MM Mobility Management MM messages are sent between the MSC and the MS in mobile networks. There are 3 types of procedures performed by the MM: - procedures to support the mobility of the MS, e.g. present location of the MS. - procedures to provide user identity confidentiality, e.g. authentication. - procedures to support CM functions. Also see BSSAP, DTAP, CM. MMS Multimedia Messaging Service MMS makes it possible to attach sound, images, graphics, photographs and video to textmessages over the mobile phone network. Also see SMS. MO Managed Object An object that can be accessed from the O&M system. Mobility Gateway IN term for an application that provides roaming between different mobile network standards, e.g. GSM and TDMA. MP3 MPEG-1 Audio Layer 3 A format to compress music files. MS Mobile Station (IN term) In the PLMN, a mobile cellular phone is referred to as an MS. An MS is used by the subscriber to communicate with the network, i.e. a mobile (cellular) phone. An MS consists of the Mobile Equipment (ME) and the Subscriber Identity Module (SIM) which is used for GSM security. The LAPDm is an SS7 protocol which facilitates the transport of DTAP and Initial MS messages between the BTS and the MS, i.e. LAPDm is the protocol used to exchange messages between the BTS and the MS. This is known as the Air-interface, or the Um-interface. The BSS and the Ericsson Base Station System comprises the BSC and the BTS in GSM and CME 20. The BSS connects the MS to the SS. Also see GSM, SIM, ME. MSC Mobile Switching Center (IN term) or Mobile Services Switching Centre One of the SS components. The switching equipment in the PLMN is called the MSC. The MSC is the central co-ordinating element in the cellular mobile network. MSCs are frequently implemented as GMSCs with inter- connections to other networks, e.g. PSTN, ISDN, IN and mobile networks. The A-interface is the interface between the MSC and the BSS. Also see SS, GSM, A-interface. MSISDN Mobile Station ISDN number (IN term) See GSM. MSU Message Signal Unit (SS7 term) An MSU is one of the 3 SU types. MSUs are sent between SPs and contain call control and signalling network information. MSUs are used for the transmission of signalling information from the UPs and APs, network management information or testing and maintenance information from MTP level 3. MSUs convey information for the control of calls and about the configuration of the signalling network. MSUs are sent between SPs and contain call control and signalling network information. Also see SU, MTP. MSU Michel Sundin The author of these guidelines. MTP Message Transfer Part (SS7 term) The MTP is that part of the SS7 node which is responsible for the secure and reliable transmission of signalling messages between the nodes (UPs). The MTP provides a reliable transport system for SS7 messages. MTP acts as a common message transfer system for the different APs and UPs in the node. Signalling messages are transferred as SUs. Note that all messages, once they enter the MTP, are referred to as SUs. SS7 messages are packed into a standard format, called SUs, by the MTP. See SU for more info about the three different SU types. MTP functions include delimitation of SUs by means of flags which mark the beginning and end of an SU, link failure detection and alignment, link recovery, error detection, and error correction by retransmission. The MTP also ensures that SUs are sent to the correct destination and it informs all SPs of any changes in the signalling network, e.g. link failure. The SCCP-MTP combination is often referred to as the NSP. The SCCP-MTP combination corresponds to layers 1-3 in the OSI model. The operations of the MTP are subdivided into three functional levels which correspond to levels 1-3 of the OSI model, while the UPs and APs constitute OSI levels 4-7. Levels 1 and 2 deal with signalling link functions (ensure that errors are not introduced in the SUs, SUs are sent in the correct sequence, SUs are only sent once) and level 3 deals with message handling and network management functions. MTP level 1 defines the Signalling Data Link (SDL) and the means to access it. It consists of a transmission channel, e.g. a 64kb/s channel, and a semi-permanent link through an electronic switch. Level 1 defines the SL itself and the means of access to it. MTP level 2, which encompasses the Signalling Terminal (ST), consists of four Signalling Link (SL) functions: - SU delimitation by means of flags which mark the beginning and end of an SU. - Alignment of SLs by sending specific messages using LSSUs. - Error detection in an SU using the ChecKsum (CK) bits of the SU. - Error correction by retransmission of faulty SUs using the FSN, BSN, FIB and BIB fields of the SU. (Also see SU.) MTP level 3 ensures that SUs are sent to the correct destination and that all SPs in the network are informed of any changes to the network. The functions of level 3 are divided into two main categories, namely message handling functions and network management functions. Message handling functions: Messages can be generated by the APs, UPs, network management functions. The message handling functions manage these messages and those which come from the SL. Message handling functions involve: - Discrimination (filtered for rerouting, i.e. checking incoming SUs and determining if they are for this SP or for routing to another SP, i.e. checks end destination of incoming SUs, i.e. determines if an SU should be sent to the distribution function for transfer within the SP or to the routing function for transmission to another SP) - Distribution (directs SUs to the correct destination, i.e. to the appropriate UPs, APs or network functions within the SP, i.e. examination of the Service Indicator (SI) bits to determine where, within the SP, the SU will be sent) - Routing (directing to the correct SL, i.e. receiving outgoing SUs and assigning them to SLs, i.e. routing of SUs using the DPC and the SLS or SLC to select the LS and the SL). Discrimination | Distribution <-No- Is SU for another SP? -Yes-> Routing | | Destination of SU in SP? Destination of SU | in the network? |--> UPs | |--> APs |--> SL 1 |--> Network management functions |--> SL 2 |--> SL 3 Those parts of the incoming SU used in discrimination are: - the Network Indicator (NI) in the SIO (see SU) - the DPC in the routing label in the SIF (see SU) Network management functions: Use messages to control and manage the signalling network itself, e.g. in the event of loss or congestion of a particular SL, the network management functions would manage and control the setting up of an alternative SL. Network management functions involve Signalling Traffic Management (STM), Signalling Route Management (SRM), Signalling Link Management (SLM). See respective acronym. The following chart lists some of the messages used for SS7 network management: SLM --- Link activation: LSSUs Alignment: SIOS, SIN, SIE Testing: SLTM, SLTA Link restoration: LSSUs STM --- Changeover: COO, COA Changeback: CBD, CBA Emergency changeover (one ST faulty): ECO, COA Emergency changeover (both STs faulty): ECO, ECA Forced rerouting: In response to a TFP Controlled rerouting: In response to a TFR or TFA SRM --- Route unavailable: TFP (Transfer prohibited) Check route status: RST (Route Set Test) Route available: TFA (Transfer allowed) Route restricted: TFR (Transfer restricted) The ISUP uses the end-to-end signalling capabilities of the SCCP for the transfer of non circuit-related signalling information. The SCCP then interworks with the MTP. The combination of SCCP and MTP is called the Network Service Part (NSP). Also see SS7, AP, UP, SCCP, NSP, SU, STM, SRM, SLM, ISUP. |
| N | Top of Glossary |
Network Layer The Network Layer (layer 3 of the OSI model) provides a transport channel for the transmission of data between transport layers in different systems. The layer establishes, maintains and releases connections between the systems and handles address and routing of circuits. The main functions of this layer are: - to establish, maintain and release connections between systems - addressing and routing Also see OSI. Network Redundancy See Geographical Network Redundancy. NFS Network File System (TCP/IP additional application) NFS: - The user sees the NFS server disk as local. - Files can be splitted. NI Network Indicator (SS7 term) The NI is part of the Sub-Service Field (SSF) of the Service Information Octet (SIO) of an MSU. It is used to identify the signalling network to which the MSU belongs, i.e. national or international, and the different level 4 parts. Also see MTP, SU. NIS Network Information Service (IN term) NMC Network Management Centre (IN term) Node TelORB term for a cluster of interconnected TelORB processors. Same as a zone. Node In SS7, a node is an SS7 network location where signalling messages are processed, i.e. an SP. Non-circuit related signalling An SS7 term for the transfer of information which does not refer to any particular circuit, e.g. information relating to the operation and maintenance of the network. Also see SS7, SCCP, Circuit related signalling, MAP, Freephone, TC. NPCI Network Protocol Control Information (SS7 term) The NPCI is a field in a DT message. It contains the connection reference parameters. Also see DT, NSDU, SCCP. NRG Network Resource Gateway (Former Service Capability Server (SCS)) The Ericsson NRG provides open application programming interfaces (APIs) for call control and user interaction according to the Parlay/3GPP-OSA standards. NSDU Network Service Data Unit (SS7 term) The NSDU is a field in a DT message. It contains the user data. Also see DT, NPCI, SCCP. NSP New System Platform (Currently TSP) (TelORB term) NSP Network Service Part (SS7 term) Part of AP and MTP) The NSP is made up of the MTP and the SCCP. The SCCP-MTP combination is often referred to as the NSP. The SCCP-MTP combination corresponds to layers 1-3 in the OSI model. The ISUP uses the end-to-end signalling capabilities of the SCCP for the transfer of non circuit-related signalling information. The SCCP then interworks with the MTP. The combination of SCCP and MTP is called the Network Service Part (NSP). Also see SS7, AP, MTP, SCCP, ISUP. NTP Network Time Protocol (IN term) |
| O | Top of Glossary |
O Out of Alignment (SS7 term) Out of Alignment is one of the status indications of the Status Field (SF) of an LSSU. Status indication 0 (letter) is transmitted when the initial alignment has been started and neither of the status indications N or E has been received from the link. Also see SU. O&M Operation and Maintenance OA&M Operation, Administration and Maintenance OB Object Block A container of OUs. (TelORB term) ODBMS Object Database Management System ODMG Object Database Management Group OMAP Operation and Maintenance Administration Part (SS7 term) (Part of AP) The OMAP is that part of the SS7 node (AP) which is used to generate messages regarding the operation and maintenance of the network. The specific signalling requirements for operation, maintenance and administration of the network are provided by OMAP. APs that use ISP and TCAP are, e.g. MAP and OMAP. OMAP is used for the operation and maintenance of the telecommunications network. E.g. for operation and maintenance in the PSTN, OMAP handles the following tasks: - Management of routing data - Circuit validation - Testing and measurement - Statistics collection OMAP interworks with TC, SCCP and MTP. Also see AP, TCAP, ISP, MAP. OMC Operations and Maintenance Centre (IN term) Also see OMAP, TC. OMG Object Management Group OP Originating Point (SS7 term) An SS7 signalling message is generated at one SP and sent to another. The SPs are called the OP and DP, respectively. OPC Originating Point Code or Origination Point Code (SS7 term) The OPC is that part of the label in a signalling message which uniquely identifies the SP in which the message originated. The originating and destination SPs are identified by an OPC and a DPC, e.g. OPC is 300 and DPC is 400. The OPC and DPC are contained in a part of the SS7 labelled message called the Routing Label. Also see MTP, SP, SS7, STM, SU, TFP, TUP. Open system An open system is a system which is open to others for the purpose of information exchange. The development of an open system is facilitated by the use of common, clear and standard rules for communication, i.e. the protocols. ORB Object Request Broker Originating exchange The originating exchange is the exchange where the telephone call begins. The A-subscriber's line is normally connected to this exchange. In SS7, the term originating exchange refers to the exchange which generates or sends a message. OS Operating System OS Out of Service (SS7 term) OS is one of the status indications of the Status Field (SF) of an LSSU. It indicates that the link on which the LSSU is transmitted is out of service and can neither receive nor transmit MSUs. Also see SU. OSI Open Systems Interconnection The OSI model is a seven-layer model developed by the ISO as a standard for network communications architecture. The OSI model is a standard for the development of protocols for communication between open systems. The basic concepts underlying the OSI model are that - a communication process can be divided into separate, defined functions - associated functions can be grouped - these groups of associated functions can be constructed into a layered model The protocol is the set of rules governing the exchange of data between a layer in one system and a similar (peer) layer in another system. In OSI terms, the protocols govern the exchange of data between corresponding layers. The OSI model is now recognized as the standard for the modelling of communications for telecommunication applications. The OSI model is divided into 7 layers, each defining an aspect of communication between two applications. The OSI layers form two groups: - Layers 1 to 3 (bottom layers) define the functions for the transfer of information through the network. - Layers 4 to 7 define the functions related to end-to-end communication. The OSI layers are named as follows: - Layer 7: Application Layer (All) - Layer 6: Presentation Layer (People) - Layer 5: Session Layer (Should) - Layer 4: Transport Layer (Try) - Layer 3: Network Layer (Not) - Layer 2: Data Link Layer (Drink) - Layer 1: Physical Layer (Pepsi) The different layers are individually described in this glossary, just look them up. The purpose of each layer in the OSI model is to carry out part of the communication process in a well defined way. Each layer carries out its function independent of all other layers and it also communicates with the equivalent layer in other systems. E.g. the encryption function in layer 6 of one system has the companion function decryption in layer 6 of the other system. Companion functions in similar layers of two different systems are called peers. In OSI, peers communicate with peers and peer protocols govern peer to peer communication. Each layer is a service provider (to the higher layer) and a service user (of the lower layer). A layer communicates with the layers above and below it using primitives. Primitives are commands and the respective responses passed between layers in the same system. See Primitives. As data is transferred from layer to layer, each layer adds its own protocol control information and then passes the data on to the next layer. This is called layer enveloping. In layer enveloping the data to be communicated is generated at layer 7 and passed to the lower layers. Each layer adds its own Protocol Control Information to the data - in effect each layer places the received data in a "new envelope" and passes it to the next lowest layer. The lowest layer is responsible for transmitting the data over the physical medium. At the receiving end, each "envelope" is opened at the peer layer and its contents passed to the next highest layer. OSI is concerned with defining the interfaces between layers rather than the implementation of the layers themselves. The well defined structure gives OSI a modularity which means that a functional change in one layer will not affect functions in another layer. OSI supports two classes of service: - Connection-oriented service - Connectionless service Also see SS7 (e.g. SS7 - OSI mapping). OU Object Unit (TelORB term) Contains C++ or java implementation of one or several objects. |
| P | Top of Glossary |
PAM Pass Along Message (SS7 term) A PAM is a message in the ISUP that may be sent in either direction to transfer information between two SPs, along the same signalling path as that used to establish a physical connection between the two points. Parameter An SS7 term for the elements of information transferred between layers in primitives, e.g. the called and calling party addresses and the user data. Parlay Server A server node which publishes a CORBA server interface which allows "external IN applications" to communicate with the telephone network and request services and reroute/answer calls. (Source: uabcsru, 010206) PBA Printed Board Assembly PC Personal Computer PCB Printed Circuit Board PCI Peripheral Component Interface PCM Pulse Code Modulation PCM is a technique for converting analogue signals to digital. PCM systems use TDM to multiplex several channels onto one bearer channel before transmission. PDA Personal Digital Assistant PDF Portable Document Format PDU Power Distribution Unit Used in high-ohmic or three-conductor power systems. PDF Portable Document Format Peer entity In a layered communication model, peer entities are entities at the same layer in two different systems which communicate with one another using a protocol. Also see OSI. PHY PHYsical interface circuit for Ethernet Physical Layer The Physical Layer (layer 1 of the OSI model) provides an essential error-free point-to-point circuit between network layers. The layer contains resources for error detection, error correction and flow control. The Physical Layer is concerned with transmitting and receiving data bits over a communication channel. It must provide a physical connection for the transmission of data and a means by which to activate and deactivate that connection. It contains functions for converting data into signals compatible with the transmission medium. Also see OSI. PID Process IDentity (UNIX term) PLGL Processor Loading Group Loader (TelORB term) TelORB processor with loading characteristics, i.e. TelORB processors 1 & 2. PLMN Public Land Mobile Networks (IN term) The mobile telephony network. The PLMN is the network that provides cellular mobile telephony. It is composed of subscriber, transmission and switching equipment. Also see C7, HLR, MS, MSC, SCCP, SS7, TC. PMC PCI Mezzanine Card PNR Partitioned Network Redundancy (TelORB term) PO Processor Outage (SS7 term) PO is one of the status indications of the Status Field (SF) of an LSSU. A PO occurs when, due to factors at a functional level higher than level 2, use of the link is precluded. Also see SU. Point code In SS7, the point code is a binary code which uniquely identifies an SP in a signalling network. POT Persistent Object Type (TelORB term) Database "DU". POTS Plain Old Telephony Service (IN term) PRA Product Release A PRB Product Release B Premium rate Example of an IN service. (IN term) Premium rate implies that the charge for the call is higher than for ordinary calls and is normally used to provide information services, such as sports results or weather forecasts. Presentation Layer The Presentation Layer (layer 6 of the OSI model) defines how data is represented. It transforms the syntax used in applications into the common syntax needed for communication between applications, e.g. Teletex to ASCII. This layer transforms the data into the correct code, format or syntax for the particular application, e.g. ASCII code is a common format. Encryption and decryption can also be included in this layer, if security and confidentiality are required. Encryption is very similar to "scrambling" used in radio where data is scrambled into a format which is unrecognizable unless the key to the code is known. Also see OSI. Primitives Primitives are commands used by a layer in the OSI model to communicate with the layers above and below it, i.e. primitives are used for communication between layers in the same system. A primitive is a command or the respective response associated with the services requested from one layer by another layer. Requests and their associated responses which are passed between layers are called primitives. Each layer has its own set of primitives. The syntax of a primitive is: Layer identifier Generic name Specific name Parameter (One of 4 (Optional specific parameter names) field) Layer identifier: Indicates the layer providing the service. E.g. in SS7 `N-' is used to identify the SCCP service primitives, e.g. N-. Generic name: This field indicates the generic name of the service being requested. Examples of generic names are: - Connect (initiating the setting up of a connection), i.e. N-CONNECT. - Data (indicating that the primitive contains user data), i.e. N-DATA. - Disconnect (requesting the release of a connection), i.e. N-DISCONNECT. Specific name: There are 4 specific names indicating the direction and function of the primitive: - Request (issued by a higher layer to envoke a service provided by a lower layer) - Indication (issued by a service provider to acknowledge a request and indicate that the service will proceed) - Response (issued by a higher layer in response to an indication to indicate acceptance) - Confirmation (issued by a service provider to indicate completion of a service) Optional parameters: Parameters are the elements of information which are transferred between layers, e.g. Called address, Calling address, Connection identification, and User data. The SCCP primitives and their parameters differ depending on if the service is connection-oriented, connectionless, or if it is primitives for SCCP Management, MTP or ISUP. OSI defined service primitives are used for communication between: - The SCCP User and the SCCP - The SCCP and the MTP Also see OSI, CHA, DHA. Process type There are 5 types of processes in TelORB: 1. Central, Static, Unique 2. Central, Static, Replicated 3. Central, Dynamic, Replicated 4. Key-Identified, Dynamic, Unique 5. Installed or Database Object, Identified, Static, Unique. PROM Programmable Read Only Memory Protocol A set of rules for communication between peer entities. Some examples of SS7 protocols for GSM: - A-interface: Interface between MSC and BSS. - DTAP: Sends CM/MM messages between MSC and MS. - BSSMAP: Sends messages between MSC and BSS. - Initial MS: Sent transparently between MSC and MS. - LAPD: Exchanges messages between BSC and BTS. (Also known as the A-bis interface.) - LAPDm: Exchange messages between BTS and MS. (Also known as the Air-interface, or the Um-interface.) Also see OSI. Protocol class There are 4 classes of protocols defined within the connection-oriented and connectionless services, 2 for each service. These determine the type and level of service provided. The 4 protocol classes are: - 0 - basic connectionless class: Provides a purely connectionless service. Data units, called Network Service Data Units (NSDUs), are received from the SCCP Users and are transferred across the network independently. The data units may arrive out of sequence. - 1 - sequenced connectionless class: Provides an an enhanced connectionless service. It provides a sequenced delivery. The same SLS value is inserted in the routing label of each message to help provide sequenced delivery. The MTP ensures, as far as possible, that these messages take the same route through the network. - 2 - basic connection-oriented class: A simple connection-oriented service. A bi-directional transfer of data packets between the SCCP Users is performed by setting up a temporary or permanent signalling connection. The quality of service, in terms of message loss, undetected errors and mis-sequencing, is the same as that offered by the MTP to its user parts. Class 2 offers a sequenced delivery. This is achieved by inserting the same value in the SLS field of each message. The data packets are transferred in Data Form 1 (DT1) packets. - 3 - flow control connection-oriented class: Supports the features of class 2 (sequenced delivery, same quality of service as the MTP) and provides additional features. These include a flow control mechanism additional to that provided by the MTP. Flow control is the regulation of the rate of data flow between adjacent layers or between peers. The flow control operates in both directions, i.e. the receiving node can limit the data flow from the sending node. A connectionless message may belong to either or both protocol class 0 and class 1 (e.g. UDT). A connection-oriented message may belong to either or both protocol class 2 and class 3 (e.g. CR). For connection-oriented services, the protocol class for a signalling connection is negotiated at call establishment. For connectionless services, if the SCCP User requests a sequenced delivery, the class 1 protocol is selected. Otherwise the class 0 protocol is selected. Also see Connectionless service, Connection-oriented service. vTo30IsSLiRPYI PSDN Packet Switched Data Network (IN term) PSTN Public Switched Telephone Network (IN term) The PSTN is the name given to the public telephone system providing analogue subscriber access, i.e. the ordinary telephony network. In the PSTN, the TUP is used to support normal telephony functions. Also see OMAP, TUP. PT Process Type (TelORB term) See Process type. Process "DU". PTT Post, Telephone and Telegraph company Prior to deregulation, the PTT was the sole provider of telephony services in a particular country. PXE Pre-Execution Environment |
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Q.700 Series The Q.700 Series of Recommendations is the ITU-T specifications relating to SS7. |
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R Release (TelORB term) TelORB used the term 'AD' as a name of a TelORB release, e.g. AD12. After TelORB release AD12 the term 'AD' changed to 'R' (as in Release), e.g. TelORB release R13. REL RELease (SS7 term) The REL message is a message in the ISUP, which is sent in either direction to indicate that the circuit is being released and is ready to be put into the idle state on receipt of the RELEASE COMPLETE message. Rerouting SS7 term - Forced rerouting is used when a Signalling Route becomes unavailable. All traffic is stored in a forced rerouting buffer. Forced rerouting is the diversion of traffic to an alternative route in the event of a route failure. - Controlled rerouting is used when traffic is directed from an alternative signalling route back to the normal signalling route which has become available, or when a Transfer Restricted (TFR) SU is received, indicating congestion on a signalling route. If no alternative routes are available to an SP, the STM function instructs the UPs not to send any more messages to that SP. RIP Routing Information Protocol Used in TelORB in connection with VIP addressing. Also see VIP, DIP. RMON Remote MONitoring RMS Rack Monitoring System A box from the vendor Knuerr, which, in TelORB, is used to detect alarms for erroneous HW. Router An entity which lets a LAN communicate with other LANs. A router reads the netaddress and therefore requires a net protocol (e.g. IP, IPX, XNS). Also see Subnetmask. Route Status Table SS7 term. A Route Status Table is contained in each SP. The information that is given in this table includes the destination (the destination point of the route), the LS (connecting the two SPs) and the status (availability of the destination via the LS). Routing SS7 term. Routing is one of the message handling functions of level 3 of the MTP. Routing uses the DPC and SLS or SLC of the MSU to select the LS and SL. RPI Regional Processor Integrated A HW module. RPM RedHat Packaging Manager Upgradeable unit in Linux which corresponds to TelORB's LM. rtid Runtime identity (TelORB term) Runtime identities (rtid) are integers that identifies system entities such as POTs, DUTs, PTs and dialogue peers in a TelORB system. The rtids are checked out from a rtid-server by epbuild the very first time a SWI (or OU), containing some of these system entities, is built. The rtids are stored in files like SWI_or_OU/spec/delosInfo/*.delosrtid Runtime identities should never be changed. This is especially important if the rtid exists in a running system that you want to upgrade in runtime. If you try to change a rtid then the upgrade will fail. To keep your rtid's intact there are some rules to remember during development: 1. You must include the delosrtid files into the CVS repository. In practice this means that you must do 'cvs add' on newly created delosrtid files. In fact, delosrtid files are the only generated files that should be included in the repository. 2. Never delete delosrtid files in a SWI or OU that has been checked out. The reason is that epbuild will generate new delosrtid files with new rtids if any delosrtid files are missing. If you delete the delosInfo directory by mistake, then do a 'cvs update' to check it out again. (The only time it would be ok to delete a delosrtid file is if you really want the corresponding entity to cease to exist.) (Source: E-mail from uabseri, 2001-06-19) |
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SAM Subsequent Address Message (SS7 term) The SAM is an address message in both the TUP and ISUP. If the IAM does not carry all the digits in the Called Party Address, the SAM is used to carry any remaining digits. SCB-RP Support and Connection Board with RPI SCC Source Code Component (TelORB term) SCCP Signalling Connection Control Part (SS7 term) (Part of AP) The SCCP can be used to establish a logical connection as opposed to a physical connection for the transfer of signalling data across the network. The layer 3 OSI functions provided by the SCCP are: - Routing - Translation - Management The ISUP uses the services of the SCCP to support end-to-end signalling. The SCCP provides additional functions to the MTP to cater for both circuit-related and non circuit-related signalling information, i.e. SCCP supports connectionless/connection-oriented services for the transfer of circuit and non circuit-related applications. The SCCP was introduced to enhance the message carrying capabilities of the MTP. SCCP supports circuit-related and non circuit-related signalling. The SCCP-MTP combination is often referred to as the NSP and it corresponds to layers 1-3 in the OSI model. SCCP service types: - Connection-oriented service is one type of service offered by the SCCP protocol. A logical signalling connection is established between the network users. This connection can be either temporary or permanent. - Connectionless service is one type of service offered by the SCCP protocol. No logical signalling connection is established between the service users. All routing information required to route the data to its destination must be contained in each data packet. A connection in this context is a relationship between nodes. The SCCP was added to the SS7 node to: - supplement the message carrying capabilities of the MTP by supporting non circuit-related signalling. - allow the provision, in combination with the MTP, of the full OSI layer 3 services to users of SS7. - avoid major changes to the MTP itself. Before the development of the SCCP, a physical connection was required for sending signalling data through the network. Now the SCCP can be used to establish a logical connection for the transfer of signalling data across the network, instead of using a physical connection. Data can be transferred through the network with or without the use of the logical connections. The layer 3 OSI functions provided by the SCCP are: - Routing: The SCCP routing function routes all incoming and outgoing messages to their appropriate destinations. This allows specialized routing within the network, e.g. it allows messages to be passed between specialized nodes such as mobile network VLRs. The SCCP routing function recognizes other address formats in addition to the signalling point code of the MTP. E.g. the SCCP recognizes as an acceptable code the dialled digits used by the MAP to address a called party. Also see SCR. - Translation: The SCCP supports a powerful translation function. The upper layers generate extended and detailed signalling addresses called Global Titles (GT). The SCCP translates these GTs into network addresses which can be used by the MTP. The network addresses used by the MTP are: - SPCs (identifying the SPs) - SSNs (which are SCCP User identities) Also see SCR. - Management: The SCCP provides management capabilities. The function of SCCP management is to provide procedures to maintain network performance by rerouting in the event of failure or congestion of the network. SCCP management functions are of 2 types: - Management of SPs - Management of SSNs E.g. SCCP management is responsible for informing other nodes in the network of the availability of the SCCP Users (subsystems). The SCCP is informed of the status of the signalling network by the MTP in the primitives: - MTP-Pause Indication - MTP-Resume Indication - MTP-Status Indication Also see SCM. The SCCP has 4 functional blocks: - SCCP Connection-Oriented Control (SCOC) - SCCP ConnectionLess Control (SCLC) - SCCP Management (SCM) - SCCP Routing ((SCR) See respective acronym for further information. Also see ASCII picture at SS7. The Users of the SCCP services are: - ISUP - APs which interface with the SCP through TC, e.g. the MAP and the INAP (and OMAP). Direct users of the SCCP (those which do not use TC to access the SCCP) are called subsystems. The SCCP addresses these users by using SSNs. The SCCP Users consider the SCCP to be the underlying network. The ISUP uses the end-to-end signalling capabilities of the SCCP for the transfer of non circuit-related signalling information. The SCCP then interworks with the MTP. The combination of SCCP and MTP is called the Network Service Part (NSP). The SCCP uses the transport capabilities of the MTP to provide its users with the facility to transfer data to other nodes. The MTP views the SCCP as any other user of its services. As with other users, e.g. the TUP, the SCCP generates messages. Data passed from the SCCP Users is included in the user message or data field of the SCCP message. The SCCP adds additional control and routing information and then passes the message to the MTP. The SCCP message is then carried in the SIF of an MTP message. The SCCP provides the capability for the: - set-up of logical signalling connections - release of logical signalling connections - transfer of data with or without logical signalling connection Like the other SS7 parts, peer SCCPs communicate using Messages. There are 21 SCCP message types, e.g. CR Connection Request and UDT Unitdata. See special tables for SCCP messages and their parameters (not included in these guidelines). There are 4 classes of protocols defined within the connection-oriented and connectionless services, 2 for each service. A connectionless message may belong to either or both protocol class 0 and class 1 (e.g. UDT). A connection-oriented message may belong to either or both protocol class 2 and class 3 (e.g. CR). A Management message is carried using the connectionless service. The format of an SCCP message is similar to that of an ISUP message, i.e. an SCCP message contains: - Routing label: Contains information necessary to route the message to its destination point, i.e. OPC, DPC and SLS. The MTP guarantees, to a high level, that all messages which contain the same SLS code will be delivered in sequence. Note that the SCCP message has no CIC. - Message Type Code: As in ISUP messages, the Message Type Code part is mandatory for all messages. It uniquely identifies each message. The contents of this field define the format of the remainder of message (i.e. what mandatory, variable and optional parameters it contains). This field is one octet in length. - Mandatory Fixed Part: As in ISUP messages, the Mandatory Fixed Part contains those parameters which are mandatory and of fixed length. - Mandatory Variable Part: As in ISUP messages, the Mandatory Variable Part contains those parameters which are mandatory and of variable length. - Optional Part: These are parameters which may or may not be included in a message. SCCP messages are transferred to the MTP where they are embedded in the SIF of the MSU. The SI code in the SIO indicates that the message is an SCCP message. Examples of SCCP messages are: - The Connection Request (CR) message: Sent by the calling SCCP to the called SCCP to request the setting up of a signalling connection. - The Data Form 1 (DT1) message: Sent by either end of a signalling connection to pass SCCP User data between SCCP nodes. - The Released (RLSD) message: Sent in the forward or backward direction to indicate that the sending SCCP wishes to release the connection and associated resources. - The Unitdata (UDT) message: Used for the transfer of data between SCCP Users in a connectionless mode. All messages sent and received by the SCCP contain addressing information. SCCP messages contain Calling/ Called Party Address parameters which uniquely identify the origination and destination points for the message. These parameters have the same structure, i.e.: - An Address Indicator: This is a single octet indicating the type of address format in the address field. Address Indicator encoding: Bit 1: Point code indicator (1=Address contains an SPC) Bit 2: SSN indicator (1=Address contains an SSN) Bit 3-6: GT indicator Bit 7: Routing indicator (0=Routing should be based on GT) (1=Routing should be based on the DPC in the MTP routing label and the SSN in the Called Party Address) Bit 8: Reserved for national use - An Address: Consists of a combination of the following format: SPC (14 bits), SSN (1 octet) and GT (variable length). SCCP procedures (Call example): - Connection establishment: In the connection-oriented service, a signalling connection is established, and data is sent in sequence. The SCCP User (e.g. ISUP) sends the called party address to the SCCP (in own node) in the primitive N-connect request (see Primitives). The SCCP Connection-Oriented Control (SCOC) function controls the establishment and release of a connection-oriented service. On the receipt of the N-connect request, the SCCP examines the called address to identify the node to which the connection must be established. The address may be a combination of a GT, an SSN or an SPC. If the address is in GT format, it must be translated so that it can be understood by the MTP (in own node). If resources are available to establish the connection, the SCCP: - assigns a source local reference number (LRN) to the connection. This is a local identity number for the selected SCCP connection. - assigns an SLS code for the connection. - associates the called address with a connection. - negotiates the protocol class of the signalling connection. - sets the initial credits if the protocol class provides for flow control. - sends a Connection Request (CR) in the primitive MTP-Transfer Request. The SCCP User (e.g. ISUP) may request the SCCP to set up a signalling connection and return the information to the ISUP for transmission of an ISUP call set up message. For this method the ISUP notifies the SCCP of the need for a connection using a request type 1 primitive. In the MTP, the CR message is enveloped in the SIF field (see SIF) and transported through the network (to the MTP of the destination node). In the connection-oriented service, the messages are routed in sequence so the same SLS values will be inserted into all the messages. The MTP will ensure in as far as possible that messages with the same SLS values will be transported throughout the network in sequence. At the remote end (destination), the MTP sends the CR message to the SCCP in the primitive MTP- Transfer Indication. The message is sent to the routing function block SCR in the SCCP. The called party address is examined by the routing function to see if the address is a local one. If the address is local: - the protocol class for the connection is established and if required an initial credit for flow control is assigned. - the SCCP sends the user data to the SCCP User in the primitive N-connect indication. - if the SCCP User can establish a connection it informs the SCCP in the primitive N-connect response. - a source local reference number (LRN) and an SLS code are assigned to the connection. - the SCCP User data is enveloped in a Connection Confirm (CC) message and sent to the MTP for transmission. When a Connection Confirm (CC) message is received (by the MTP) at the origination node: - it is sent to the SCCP (in own node) in the primitive MTP-Transfer Indication. - the protocol class of the connection and the initial credit are updated based on the values in the incoming message. - the SCCP User is informed of the successful establishment of the signalling connection in the primitive N-connection confirmation. - in the SCCP, the received local reference number (set by the destination node) is associated with the connection. - a connection is now established. If the call passes through an intermediate node: - a local reference number (LRN) and SLS code are assigned to the incoming connection in the intermediate SCCP. - an outgoing connection is established in the same way as in the origination node. - an associated (coupling) is made between the incoming and outgoing connections. - a CR message is sent to the destination node. If a connection cannot be established at the destination node: - the SCCP User at the destination node sends an N-disconnect request to the SCCP (in own node). - a Connectio Refused (CREF) message is sent to the originating node. - Data transfer: Once the connection is established, the transfer of data can begin. The SCCP User data is transferred to the SCCP (in own node) in the primitive N-Data request. The user data is packed into Data (DT) messages. The DT message contains: - NPCI. This contains the connection reference parameters. - NSDU. This contains the user data. If the size of the user data is too large to be transferred within one message, segmentation of the data over several DT messages is permitted. The more-data (M-bit) in a DT indicates that the NSDU has been segmented. (An extra bit (M-bit)). The SLS field in all of the routing labels is given the same value to permit message sequencing. The flow control procedure are decided by the protocol class for the connection. (At intermediate nodes, data messages are passed by linking incoming and outgoing connections, through LRNs.) At the destination node, the data is passed to the SCCP User in the primitive N-Data Indication. A limited amount of data may be transferred in the CR, CREF and Released (RLSD) messages. All DT2 messages sent must be acknowledged (from destination node to origination node). Each DT2 message contains a Send Sequence Number (PS) and a Receive Sequence Number (PR). With every new DT2 message sent, PS is incremented. DT2 messages are acknowledged by: - the sending of a Data Acknowledge message to the originating node. The PR value of this message will be set to the PS value of the DT2 message that is being acknowledged. - sending a DT2 message to the originating node. The PR value of this message will equal the setting of the PS value of the original DT2 message sent. The number of DT2 messages which can be sent without acknowledgement is set during connection establishment when the flow control window size is negotiated. Acknowledgement (AK) messages are also sent on the connection in cases where: - no DT2 messages are being sent on the connection. - a node is encountering congestion on a connection. Recall that a connection-oriented class 2 message is called Data Form 1 (DT1) while a connection- oriented class 3 message is called Data Form 2 (DT2). The flow control procedures apply to the class 3 protocol only. Also recall that the M-bit in the DT2 indicates to the destination node if the user data (NSDU) has been segmented over several messages. - Connection release: The release of an established connection may be performed by the SCCP. The SCCP user initiates a release of the connection by sending an N-Disconnect request primitive to the SCCP (in own node). A release timer is started. A released (RLSD) message is transferred on the connection to the detination node. If the SCCP initiates the release, a release timer is started and an N-Disconnect Indication primitive is sent to the SCCP User and an RLSD message is sent along the signalling connection. On receipt of the RLSD at the not initiating connection release: - a Release Complete (RLC) message is sent to the node initiating the release. - the connection associated with the message is freed. - the SCCP User is informed that the connection has been released in an N-Disconnect Indication primitive. - the local reference number (LRN) associated with the connection is frozen. (The reference number is frozen to ensure that incorrect procedures are not initiated as a result of receipt of a message relating to a previously established connection section.) When an RLC message is received at the end initiating the release: - the connection associated with the message is released. - the release timer is stopped. - the local reference number (LRN) is frozen. If the release timer expires, an RLSD message is transferred on the connection every 4 to 15 seconds for an interval of up to one minute. If at this point there is no reply, a maintenance function is alerted. - Connectionless procedure: See summary further down or read the lot below. In the connectionless service, data flows in one direction only and contains its own routing information. Examples of the connectionless service are: - sending an alarm from a local exchange to a central operation and maintenance centre. - requesting a mobile subscriber's location data in a PLMN. In the connectionless service, the SCCP Users send data and addressing information to the SCCP in the primitive N-Unitdata Request (in own node). The N-Unitdata Request primitive may contain parameters for called address, calling address, sequence control, return option and user data. If the sequence control parameter is included, the class 1 protocol is selected for the signalling connection. Sequenced delivery is achieved if all subsequent N-Unitdata Request primitives contain the same sequence control value. If the sequence control parameter is not included, the class 0 protocol is selected. The SCCP sends a UNITdata (UDT) message containing the user data and its control and routing information to the MTP in the primitive MTP-Transfer Request. In the MTP, the UDT message is enveloped in the SIF and transported across the network. UDT messages transferred according to the connectionless class 1 protocol, are assigned the same SLS value in the routing label and have a higher probability of arriving in sequence at the destination node. At the receiving node, the UDT message is sent to the SCCP in the primitive MTP-Transfer Indication. The SCCP routing function (SCR) performs a routing analysis. The called party address is analysed to check if the destination address is local. If the called party address is local and the message is for an SCCP User, then the user data is delivered to the higher level in the primitive N-Unitdata Indication. If the called party address is local and the message is for the SCCP management functions, then the data is passed to the SCCP Management (SCM) function. If the called party address is not local, SCR determines the address of the next SCCP node based either on GT, or DPC and SSN. The UDT message is returned to the MTP in the MTP-Transfer Request primitive. The message is passed to the next node. This process continues until the user data has reached the correct called party address. If the SCR cannot transfer the UDT to its destination, the message return function is initiated by setting the Return Option parameter in the UDT. Return options may have the following values: - Return Message on Error: If the message is a Unitdata Service (UDTS) message, it is always discarded. - Discard Message on Error: A Unitdata Service (UDTS) message is returned to the original node. The message contains user data and reason for non-delivery, e.g. failure or congestion. At the destination node (the origin of the UDT) the primitive N-Notice Indication is invoked to inform the SCCP User of the situation. If the UDT message originated locally (in the upper layers or the SCM) and cannot be routed to the destination address by the SCR, then an N-Notice Indication is returned to the local SCCP User. The SCCP Users are then informed of the status of the signalling network by the SCCP management primitives. Summary of connectionless procedures: The transfer of data from one SCCP User in one node to another SCCP User in another node can be summarized as follows: 1. Address and routing information is sent to the SCCP from the higher layers in the N-Unitdata Request. (SCCP User to SCCP in origination node.) 2. The SCCP sends a UDT message to the MTP in the primitive MTP-Transfer Request. (SCCP to MTP in origination node.) 3. The UDT is enveloped in the SIF of the MSU. (In origination node.) 4. The MSU is transported through the network. (From origination node, perhaps via intermediate nodes, to MTP of destination node.) 5. The UDT is transferred to the SCCP in the primitive MTP-Transfer Indication. (From MTP to SCCP at destination node.) 6. User data is transferred to the higher layers in the primitive N-Unitdata Indication. (From SCCP to SCCP User at destination node.) Also see SS7, AP, MTP, NSP, Address indicator, DT message, SCLC, SCM, SCOC, SCR, SSN, UDT, Connectionless service, Connection-oriented service, Primitives, Protocol class, ISUP, SPC, SSN, GT. SCCP S? Connection Control Protocol Layer 4 of SS7. SCE Service Creation Environment (IN term) One of the main components of IN. The SCE is the system which facilitates the creation, modification and testing of IN services. The SCE defines, develops and tests IN services. The SCE allows the service providers to create new services using standard reusable software modules, called SIBs. SCLC SCCP ConnectionLess Control (SS7 term) SCLC is the subfunction in the SCCP that provides procedures for connectionless transfer of user data. Distribution and reception of SCCP management messages are also part of this subfunction. Also see SCCP, Connectionless service. SCM SCCP Management (SS7 term) SCM is the subfunction in SCCP that provides procedures to maintain network performance by rerouting or throttling the traffic in the event of failure or congestion. Also see SCCP. SCOC SCCP Connection-Oriented Control (SS7 term) The SCOC is a subfunction in SCCP that provides procedures for the establishment, supervision and release of a temporary signalling connection. It also handles the transfer of data on this connection. In other words: The SCOC functions control the establishment and release of a connection-oriented service. Also see SCCP, Connection-Oriented service. SCP Service Control Point (IN term) A server that controls the execution of all IN services in the network. It also provides the means to introduce new services in the network. One of the main components of IN. The SCP contains Service Logic Programs (SLPs) and may optionally contain customer data. In INs most of the service `intelligence' or logic of the network is contained in a central node, called SCP. The SCP is the focal point within the network, containing the service logic and the service data needed to processes all IN services. Data can also be stored in SDPs and IPs. The SCP is connected to the network exchanges in IN, called the SSPs, via a standard C7 signalling interface. One or more local exchanges may be connected to the SSP. Sometimes the SCP and the SSP are combined into one node, an enhanced exchange, called SSCP. The SCP directs the SSPs to perform functions necessary to complete an IN call such as switching and activating IPs. There can also be a C7 interface between the SCP and IP, enabling the SCP to directly control the IP. An SCP contains e.g. wireless IN service programs that allow the operator to deploy customized services quickly. The SCP has the service logic needed to process IN calls. The Service Control Function (SCF), which is located in the SCP, is the core of the IN and controls the entire process of handling calls or services by giving instructions to other logical entities. The SCF also contains the service logic and the C7 signalling capabilities. The SCP receives information from the SMS as a result of service subscriber data updates, and sends information to the SMS in the form of measurements and traffic data. The operations of the SCP include message processing (functions required to deliver a message to its correct destination within the SCP, or to the appropriate node in the network) and node operations, administration and maintenance (functions required to operate and control the SCP itself and include activities such as traffic measurement, security and error detection). To ensure reliability, two SCPs may function as a mated pair, i.e. exact copies of each other with identical data and simultaneous updating. One SCP is executing, while the other is standby. SCR SCCP Routing (SS7 term) The SCR is the subfunction in the SCCP that physically routes a message from one SP to another. The SCR is based on the MTP. The SCR subfunction relies on the MTP function to physically route the message. SCR provides point-to- point routing capabilities by means of GT translation tables. Also see SCCP, GT. Scrub A TelORB term for a background job that is constantly running to scrub the memory to decrease the risk of memory bit faults. The HW is capable of correcting 1-bit-errors in the memory, but not 2-bit-errors. A bit correction does not take place when writing to a bit, but when reading a bit. When reading and writing in the memory, a checksum check is performed. The scrubbing function reads and writes in the memory to be able to discover 1-bit-errors, so that these can be corrected by the HW, before they turn into 2-bit-errors. The memory is divided into 3 parts by the scrubbing function. Each time a scrubbing starts a printout, which looks as follows, is received in the TelORB processor log: E.g. "Starting to scrub block beginning at 02000000". SCSI Service Capability Server See NRG. SCSI Small Computer System Interface SDL Signalling Data Link (SS7 term) The SDL is the physical link that connects two SPs (i.e. an SL). It provides a bearer, e.g. a 64 kb/s channel connected via a semi-permanent link, for the signalling messages. SDP Service Data Point (IN term) One of the main components of IN. The SDP is a database storage device for holding subscriber data and service parameter information. The SDP is used to store customer data externally from the SCP. The SDP can be accessed directly by the SCP. The Service Data Function (SDF), which is located in the SDP, assists the SCF (SCP) by providing data about subscribers and the network. The Service Creation Environment Function (SCEF), which is located in the SCE, handles the definition, development and testing of IN-based services. SE System Entity (TelORB term) Container of other MIs other than LMs and IDPs. Semi-permanent connection A semi-permanent connection is a software link between an incoming and an outgoing timeslot in a digital switch which can be established by command. It provides a reserved connection through the digital switch. Service Capability Server A server the, e.g. provides IN services. The service capability servers resides in the content layer in the three-layered network architecture. Service provider A service provider offers an IN service to service subscribers and service users. Service providers can be network operators, including the old PTTs, or external service operators providing a service via an existing network. Also see SMS. Service subscriber An individual or organization which offers an IN service to service users and which pays the service provider for the provision of these services. Service subscribers need to be able to customize and modify services to suit their individual requirements. Service providers can be e.g. travel agents or banks. Also see SMS. Service user An individual using IN services. A service user can access an IN service either with an access code for a particular service or with a prefix for a particular service, e.g. 800. Session Layer The Session Layer (layer 5 of the OSI model) establishes connections between presentation layers in different systems. It controls the connection, the synchronization of the dialogue and the disconnection. The Session Layer provides the means of communication between applications. It establishes, manages and terminates end-to-end connections, called sessions, between applications. Also see OSI. SF Status Field (SS7 term) The SF is a field in an LSSU. This field contains the status of the SL on which the LSSU is sent, e.g. 'OS' indicates SL Out of Service. Also see SU, LSSU. SGID System Generation IDentity (TelORB term) Used in connection with backup handling. SGSN Serving GPRS Service Node (IN term) SGW Signalling GateWay (IN term) SI Service Indicator (SS7 term) The SI is part of the SIO of an MSU. It is used to identify the UP to which the signalling message belongs. Also see SIO. SIB Status Indicator Busy (SS7 term) SIB is the term used to describe the LSSU sent on the SL when it becomes busy due to congestion and cannot carry any more signalling traffic. The Status Field (SF) of the LSSU is set to B (Busy). Also see SU. SIB Service Independent Building Blocks (IN term) Software specific to an IN service is created using software modules called SIBs, which combine together to form the complete service logic of a particular service. The SIBs sits on top of platform, containing software common to all services. When the service logic is being defined, the necessary SIBs for that service are chosen from a library of SIBs. Once the service logic has been completed, the data associated with that service (the service data) is defined. The SIB approach offers the following advantages over "hard-coded" or non-modular software implementations: Faster introduction of services, more flexible services, a wider range of services and less pressure on the network. Also see SCE. SIE Status Indicator Emergency alignment (SS7 term) SIE is the term used to describe the LSSU sent on the SL when it is being aligned under emergency conditions, i.e. when it is required urgently. The Status Field (SF) of the LSSU is set to E (Emergency). Also see SU, MTP, SL. SIF Signalling Information Field (SS7 term) The SIF is contained in MSUs only. The SIF contains the label, heading codes and data relating to the particular user transaction. Also see SU, MSU, MTP, Label, LI, TUP. Signalling In a telecommunications network, signalling is used to enable different parts of the network to communicate with each other. There are 3 types of signalling: - Signalling between the subscriber and the exchange - Signalling within the exchange - Signalling between exchanges SS7 is predominantly used for inter-exchange signalling. Signalling message In SS7, a signalling message is an assembly of signalling information which is generated by the UPs, APs and the Network Management functions of the MTP. It contains information pertaining to a call or a management transaction that is transferred as an entity. Signalling route In SS7, a signalling route is the path that a signalling message takes from an Originating Point (OP) to a specific Destination Point (DP). A signalling route is a path between two SPs. It may pass through an STP. Also see SRM. SIM Subscriber Identity Module The SIM is a smart card which contains subscriber- related information, including the IMSI number, and which can be used with any mobile equipment (ME). Also see GSM, MS, ME. SIN Status Indicator Normal (SS7 term) SIN is the term used to describe the LSSU sent on the SL when it is being aligned under normal conditions, i.e. the link is not required urgently. The Status Field (SF) of the LSSU is set to N (Normal). Also see SU, MTP, SL. SIO Status Indicator Out of alignment (SS7 term) SIO is the term used to describe the LSSU which is sent when initial alignment of the link is has begun and neither SIN nor SIE have been received. The Status Field (SF) of the LSSU is set to O (Out of alignment). Also see SU, MTP, SL, SI. SIO Service Information Octet (SS7 term) The SIO is a field contained only in MSUs. It consists of the SI and the SSF. This information identifies the UP and the signalling network to which the message belongs. See SU, NI, SSF. SIOS Status Indicator Out of Service (SS7 term) SIOS is the term used to describe the LSSU which is sent on, or after, power-up of a link until initial alignment is started. The Status Field (SF) is set to OS (Out of Service). SIP Session Initiation Protocol SIPO Status Indicator Processor Outage (SS7 term) SIPO is the term used to describe the LSSU which is transmitted when the link cannot be used for signalling traffic due to a fault in a functional level higher than 2 (MTP). The Status Field (SF) is set to PO (Processor Outage). SL Signalling Link (SS7 term) An SL is a signalling path between two adjacent SPs. It is provided by level 1 and level 2 of the MTP for the reliable transfer of messages between UPs. The SL equipment consists of the SDL and the ST. When there are a number of SLs, they are referred to as an LS. The process of bringing an SL into service is called SL activation. There are two stages to link activation: - SL initial alignment - SL tests Following activation, the link is ready to convey signalling traffic. Links can be aligned by the SLM function under two different procedures: - Normal alignment: Occurs when an SL is brought into service for the first time, or an SL is being restarted and is not required immediately. - Emergency alignment: Takes place when an SL is required immediately, if no other route to the remote SP is available. The initial alignment function of MTP level 2 will carry out the alignment of the SLs as instructed by MTP level 3. During the initial alignment procedures, the LSSUs are used to convey the status information, these are: - Status Indicator Normal Alignment (SIN) - Status Indicator Emergency Alignment (SIE) I.e. LSSUs are sent between two SPs during initial alignment and links can be aligned using either the normal or the emergency procedures. SL test: After an SL is aligned, it must be tested before it can be brought into service. Test messages are sent for the purpose of testing the link. The Signalling Link Test Message (SLTM) is sent from e.g. SP A to SP B. A Signalling Link Test Acknowledge (SLTA) must be received by SP A within 100 ms in order for the link to pass the test. The format of test messages is as follows (They have similar fields to other SUs.): - Bit pattern - H1 - H0 - Label - SIO The bit pattern sent in an SLTM must also be contained in an SLTA. Once the link is brought into service, the test messages may be sent periodically, ensuring that the SL is always functioning properly. SL restoration: In the case of SL failure, a link restoration procedure is defined to restore the faulty SL. During restoration the following takes place: - Initial alignment during which LSSUs are sent - SL test, if initial alignment is successful When the signalling test is successful the link is in service and available for traffic. If an initial alignment or SL test fails, then manual intervention may be necessary. Once the fault is repaired, link restoration will take place. SL deactivation: A link which is in service can be taken out of service, e.g. when it is required for another signalling route. The procedure for this is SL deactivation and it only takes place if there is no traffic on the SL. The ST of the deactivated SL is also taken out of service. Also see SU, SS7, SS7 network, SP, ST, SLM, STM, SRM, SLC. SLC Signalling Link Code (SS7 term) The SLC is part of the label contained in the SIF of an MSU generated by the level 3 functions of the MTP. It is used to identify an SL from an LS. Also see SU, MTP, STM, Routing, TFP. SLM Signalling Link Management (SS7 term) SLM functions are part of the Signalling Network Management Functions for level 3 of the MTP. SLM controls the SLs attached to an SP, i.e. the SLM functions control the locally connected SLs by reconfiguring the LSs. SLM is responsible for LS management such as: - link activation (including alignment and testing) - link restoration and deactivation Also see SL, MTP. SLS Signalling Link Selection (SS7 term) The SLS field is part of the label contained in the SIF of an MSU originating in the UPs. It is used to select an SL from a signalling LS. Also see SU, MTP, Label, Routing. SLTM Signalling Link Test Message (SS7 term) The SLTM consists of a unique bit pattern sent between two SPs during link alignment. These messages are sent every 30 seconds. Also see SL, MTP. SME Service Management Environment (IN term) One of the main components of IN. The SME contains the hardware and software (PCs, WSs, disks, etc) used in the creation and management of IN services. Service creation refers to all the steps involved from the initial idea to for a service to the deployment of that service, while service management refers to tasks such as service installation and traffic management. Recently, the SME has come to mean the combination of both the SMS and the SCE. Also see SCP. SMS Service Management System (IN term) One of the main components of IN. The SMS is the operations system through which the SCPs and related service applications (programs and databases) are managed in the IN. The SMS collects statistics from the SCP. The SMS resides in a multi-purpose computer and provides the functionality necessary to control and administer service features offered by an IN service, and service subscriber's data and any customized service configurations. The SMS may be accessed by service providers and service subscribers. SMS operations include database administration, network testing, traffic management and network data collection. The Service Management Function (SMF), which is located in the SMS, manages the distribution, control and maintenance of IN-based services. The Service Management Access Function (SMAF) provides the human interface with the SMF, and is used, e.g., by operation and maintenance staff. The SMS must have a backup copy of all data that is provided to the SCP for the purpose of integrity testing and to restore the SCP databases if data is lost or if the SCP fails. Some of the key SMS operations include SCP database administration, service monitoring, traffic management, network data collection and user access control. The SMS receives network information from the SCP, such as traffic measurements and billing data. The SMS is the operations system through which the service provider and service subscriber personnel manage SCPs and related service applications, such as programs and databases, in an IN. Also see SCP. SMS Short Message Service (IN term) E.g. the textual message "Meet Michel at 8.30 outside the Milky Way" sent to a mobile phone. Also see CM. SMTP Simple Mail Transfer Protocol (TCP/IP base application) SNMP Simple Network Management Protocol (TCP/IP additional application) SNMP is an open standard made for Internet. It is used to monitor and control network equipment. Socket A socket is kind of a handle (handtag) to an object which handles IP communication, e.g. TCP/UDP. (Michel) Solaris The Solaris versions are named Solaris 2.6, Solaris 7, Solaris 8. SP Support Processor SP Stack Pointer SP Signalling Point (SS7 term) The SP is the SS7 node which originates, transfers or receives messages. It is identified by a unique binary code. Each node of the SS7 network where signalling messages originate is called an SP. Adjacent SPs are connected by SLs consisting of 64kbit/s PCM channels. A number of SLs, between two nodes (SPs, exchanges), are called an LS. The path connecting two SPs is referred to as a Signalling Route. SPs that do not process messages but pass them on to other SPs are referred to as STPs. Every SP is identified by a unique point code, e.g. "SP:300". To enable the system to route a message efficiently, the message must contain information to identify the originating SP and the destination SP. The originating and destination SPs are identified by an OPC and a DPC, e.g. OPC is 300 and DPC is 400. There can be many possible routes between SPs (normal route, and alternative routes in the event of failure on the normal route). SP consists of: AP | UP ------- MTP MTP level 3: Message handling, network management MTP level 2: Delimitation, alignment, error detection & correction. MTP level 1: Switching, connection, transmission When an SP becomes isolated, a TFP message is sent from the adjacent S(T)Ps. RST messages are then sent periodically to check the status of the LS (this is an SRM function, see SRM). Also see AP, UP, MTP, SU, SRM. SPC Signalling Point Code (SS7 term) The SPC is a binary code (address) that uniquely identifies an SP in a signalling network. The code (address) is used, according to its position in the label either as a DPC or as an OPC. An SPC from the SCCP can be transferred to the MTP without translation. Also see SCCP, SSN, GT. SPC Stored Program Control SPC refers to a device controlled by a program and was originally coined to describe the first telephone exchanges that included a processor and a stored program to control switching. An SPC Exchange is a digital exchange which is computer controlled. SS7 was devised to exploit the powerful processing capacity of such exchanges. SRM Signalling Route Management (SS7 term) SRM functions are part of the Signalling Network Management Functions for level 3 of the MTP. The SRM functions communicate, to every SP, information regarding signalling route availability and unavailability, i.e. route status. SRM is used by the STPs to inform SPs of route availability. The SRM function communicate to every SP and STP in the network information regarding signalling route availability or unavailability, e.g. if a route becomes unavailable due to a fault. Various procedures are used to communicate information about route availability to an SP. A signalling route between two SPs may be: - available, i.e. all SLs on that route are available - unavailable, i.e. all SLs on that route are unavailable - in restricted service, i.e. some SLs on the route are available and some are not The procedures used to communicate these states are: - transfer-allowed for available state - transfer-prohibited for unavailable state - transfer-restricted for restricted service A fourth procedure is defined to check if any changes have occurred in the route status. This procedure is called the signalling route-set-test procedure (see below). Each STP (SP) holds a route status table for each of the adjacent destination SPs that can be accessed through it. The following information for a particular destination SP (e.g. SP D) is held in an STP (SP), (e.g. SP B): - Destination, e.g. D for SP D: Value D - Link Set (LS) over which the destination SP (e.g. SP D) can be accessed by e.g. SP B: Value BC and BD - Status, contains a check mark if the route is available, 'X' if the route is unavailable and 'R' if the route is restricted. The transfer-prohibited procedure is performed at an STP when it has to notify some adjacent SPs and STPs not to route SUs for a given Destination Point (DP) through the STP. Route-set-test procedure: This procedure is used by an SP or an STP to test whether a signalling route, previously unavailable or restricted, is now available. When e.g. STP C receives the TFP message from e.g. STP B, it initiates the signalling route- set-test procedure. The Route Set Test (RST) message is sent from STP C to STP B. The function of the RST message is to check if the route status of e.g. destination D (read SP D) has changed. The same message format as that of the TFP message applies. The destination field of the RST message refers to the SP to which the route has been made unavailable, in this case SP D. STP B / | \ SP A | SP D \ | / STP C The heading code H1 contains the current status of the destination, in this case H1=0001 (unavailable). The heading code H0=0001 (identifies the message as an RST message). In STP, the actual status of LS BD is compared with the status given by the RST message. If the statuses are the same, STP B will not reply. STP C will continue to send RST messages every 30 seconds until STP B replies. A Transfer Allowed (TFA) message is sent if the state of the LS BD changes to available (H1=0101, The same message format as that of the TFP and RST messages applies). On receipt of a TFA message, the destination in question is set to available. The format of a Transfer Restricted (TFR) message is the same as that of the TFP, RST and TFA messages (H0=0100 (TFP, TFA or TFR message), H1=0011 (TFR)). A TFR message is sent to adjacent SPs when an LS becomes congested. The RST message periodically checks the availability of the restricted destination. TFR messages may also be sent in response to RST messages. Also see MTP, SP, TFP. SS Switching System (IN term) The SS is the part of the GSM network that handles the switching of the calls. It consists of the MSC and a number of databases (HLR, VLR, AUC and EIR) for subscriber data and mobility management. The SS's components include: - MSC - HLR - VLR - EIR - AUC The BSS connects the MS to the SS. Also see GSM, MS, BSS. SS7 Signalling System Number 7 (SS No.7) SS7 is a Common Channel Signalling System defined for 64kb/s operation between exchanges. SS7 conforms to international standards, is an open system, uses labelled messages (packets) and has a modular structure. SS7 can be used to support a variety of users such as PSTN, ISDN, Mobile networks (PLMN) and INs (see acronyms in this glossary). In mobile networks, SS7 is used as the basis for speech, data and node to node signalling to support the mobility of Mobile Stations (MSs). The TUP and the ISDN User Part (ISUP) are used for inter- exchange signalling between MSCs for speech/data circuits. The MAP was specifically designed for use in mobile networks. The SS7 was developed to provide generic services to applications while being independent of these services. This means that functions which are common to all applications are performed by SS7 application independent parts, i.e. APs (TCAP, ISP, SCCP). Functions which are specific to one application are performed by application specific parts, also APs (MAP, OMAP, INAP). All the additions to SS7 have been made in compliance with the OSI model. They are TCs, SCCP, MAP, INAP, OMAP. All of these applications belong to the SS7 AP. Structure of SS7: AP | UP ------- MTP AP UP ----------- ------- | | I | O || I | | | M | N | M || S | T | AP=MAP,INAP,OMAP,TC,SCCP | A | A | A || U | U | (also BSSAP,DTAP,BSSMAP) | P | P | P || P | P | UP=ISUP,TUP |-----------|| | | | TC || | | TC=TCAP,ISP (ISP not used) |-------------- | | TCAP=CSL & TSL | SCCP |===== SCCP=SCOC,SCLC,SCM,SCR |============== | | MTP | -------------------- MAP,INAP,OMAP are examples of TC-users. The advantages of SS7 are: - It is fast and efficient (64kb/s) - It provides secure transmission of data - It is a high capacity system - It is an independent signalling network - It enables interactive communication Telephony is currently the application most widely supported by SS7 (see PSTN and TUP). SS7 within the PSTN is used to support normal telephony functions , e.g. the setting up and release of calls handled by the TUP. It is also used for operation and maintenance procedures in the PSTN, e.g.: Management of routing data, circuit validation, testing and measurement, and statistics collection. These are all handled by the OMAP. SS7 is predominantly used for signalling between exchanges, i.e. inter-exchange signalling. Inter-exchange signalling is divided into three functional areas, namely supervision, selection and operation. Supervisory functions include the seizure and release of speech circuits between exchanges. Selection functions are responsible for call set-up and connection processes, e.g. sending a called party's address or sending a request for digits. Operational functions are network management and system administration, and include, e.g. blocking faulty circuits or sending indications of congestion. Inter-exchange functions are implemented by two different signalling methods, i.e. CAS and CCS, where SS7 is an example of a CCS. The function of an SS7 node is to generate and transmit signalling messages. These messages are of two types: Circuit related and non-circuit related. Circuit related signalling messages are messages which refer to a particular speech or data circuit, e.g. a message from exchange A to exchange B to release a particular speech circuit. Circuit related signalling is the signalling associated with the setting up, release or maintenance of a particular circuit. Signalling messages sent between the two end points refer to a circuit established between these end points. The circuit identity is held in the CIC of each message sent between end points. Non-circuit related signalling messages do not refer to any particular circuit, e.g. network management messages. Another example arises in mobile telephony where databases are updated with subscriber location information, over the signalling network, without reference to speech circuits. Non-circuit related signalling is the sending of signalling messages, which do not refer to a circuit, from one point to another in the network. In some cases it is desirable that signalling messages can be transferred without establishing a speech or data connection. E.g. in the freephone service, SS7 is used to request a B-subscriber's actual number from a distant database. In non-circuit related signalling no switched connection is set up. The information is transferred in signalling messages which do not contain a circuit identity. SS7 can be used to retrieve information from a database. In mobile telephony, for example, the location of a subscriber can be retrieved from a database by means of SS7 signalling messages. Within SS7, one signalling path supports many hundreds of speech and data circuits. Labelled messages are sent between exchanges or nodes, on a separate signalling path, i.e. signalling messages travel through the telecommunications network on a separate path to that of the speech. E.g., in ISDN with user to user signalling, short text messages can be sent over the signalling network between two subscribers without establishing a speech connection. Nodes in an SS7 network are referred to as SPs. Adjacent SPs are connected by SLs consisting of 64kbit/s PCM channels. A number of SLs, between two SPs (e.g. exchanges), are referred to as an LS. SPs that do not process messages but pass them on to other SPs are referred to as STPs. SS7 utilizes digital transmission, i.e. a 64 kbit/s PCM channel, between processors for the transfer of signalling messages, which enables fast call set-up times. An SS7 signalling message is generated at one SP and sent to another. The SPs are called the OP and DP, respectively. The OPC and DPC are contained in a part of the SS7 labelled message called the Routing Label. SS7 can be considered a separate network to the speech network although it uses the same infrastructure, i.e. the transmission links and exchange equipment. SS7 is modular in structure. Each node in the SS7 network consists of UPs, APs and an MTP. The UPs and APs generate the SS7 messages, while the MTP is responsible for the secure transmission of messages between the nodes. The UPs and APs generate signalling messages and send them to the MTP. In the MTP the messages are packed into standard format, i.e. SUs, and then they are sorted for distribution to other MTPs. At the receiving MTP the messages are distributed to the correct UP or AP. IAM Initial Address Message (SS7 term) After subscriber A dials, an IAM containing the dialled digits is sent to the B exchange. ACM Address Complete Message (SS7 term) When sufficient digits to route the call have been received in exchange B, exchange B sends an ACM to exchange A. SSB Subscriber Busy signal (SS7 term) If the B-subscriber is busy, the SSB message is sent to exchange A. SS7 - OSI mapping ----------------- The MTP implements layers 1-3 of the OSI model while the UP and AP implement layers 4-7. The layers in the SS7 model do not correspond exactly to the OSI layers. Levels 1 and 2 of the MTP correspond to layers 1 and 2 of OSI. The SCCP-MTP combination (NSP) provide the functions of layer 3 of OSI. TC provides the functions of layers 4 to 6 and part of layer 7 of OSI. (TC = TCAP + ISP) The ISP fits in at layers 4 to 6, however it has not been specified or implemented and is effectively not present in SS7 implementations. The TCAP layer directly accesses the service primitives provided by the SCCP. TCAP provides part of layer 7. Applications which use SS7 interwork with TCAP. Specific Application Parts carry out the communication functions of these applications. These Application Parts are located at layer 7. The ISUP and TUP provide functions for layers 4 to 7. There are a number of advantages to develop SS7 according to OSI: - It is application independent. - Changes in one layer do not effect changes in another layer. - The interfaces and communication between the layers are standardized and well defined. SS7 is e.g. used in PSTNs to improve the speed and efficiency of the telephone service. The TUP is the functional part of the SS7 node which defines the necessary signalling functions for setting up, supervising and clearing calls in the PSTN. See TUP for more info about how SS7 is used in PSTNs. SS7 was originally specified as a 4-level structure, where 3 levels consisted of the MTP and the 4th level formed the UPs. The first UP developed was the TUP. The Data User Part (DUP) was later specified to provide similar functions for data transfer, but has not been widely implemented. The ISUP was introduced to cater for the functions of the ISDN network. For information about SS7 for mobile telephony, see GSM. SS7 network Signalling System Number 7 (SS No.7) network The SS7 network consists of SPs, STPs and SLs which are used for the transfer of signalling messages. SS7 node Signalling System Number 7 (SS No.7) node The SS/ node is an exchange in the logical SS7 network (also called an SP). SSF Sub-Service Field (SS7 term) The SSF is part of the Service Information Octet (SIO) of an MSU. It contains the Network Indicator (NI) bit which is used to identify the signalling network and the different level 4 parts to which the MSU belongs. Also see SU, NI, SIO. SSN SubSystem Number (IN term) The SSN is a number (address) that identifies an SS using the SCCP either directly, like the ISUP or indirectly (via TC) like the MAP, OMAP and TCAP. The SSN is used by the SCCP to address direct users. See special table for coding of the SSN octet (not included in these guidelines). Part of the SS7 SCCP layer protocol. The SSN format can be transferred directly to the MTP without translation. Also see SCCP, SPC, GT. SSCP Service Switching and Control Point (IN term) See SCP and SSP. SSP Service Switching Point (IN term) One of the main components of IN. The SSP provides users with access to IN services. It provides any necessary switching for IN calls. The SCP is connected to the network exchanges in IN, called the SSPs, via a standard C7 signalling interface. One or more local exchanges may be connected to the SSP. Sometimes the SCP and the SSP are combined into one node, an enhanced exchange, called SSCP. The SSP detects when the SCP should handle a service and forwards the necessary service information to the SCP for the call processing. It also collects charging information. The Service Switching Function (SSF), which is located in the SSP, is the point where an IN call trigger is detected. The SSF receives instructions from the SCF (SCP) and includes functionality for switching, triggering, charging and congestion control. The SSP is an IN node which performs IN call switching and assists the SCP in the completion of calls. The main functions of the SSP are providing the SCP with the information it needs to process IN calls, performing IN call switching on request from the SCP and allowing access to IN resources, such as IPs. The SSP also performs charging, congestion control and statistic collection. When a local exchange in the PSTN recognizes an IN call, call is first routed to an SSP for handling. The SSP contain trigger tables, which include the routing information and parameters that the SCP will need for subsequent processing of the call. During the handling of an IN call, the SSPs send the relevant service information to the SCP, using standardized messages sent over the C7 signalling network. The main processing of the call then takes place in the SCP, where most of the actual `intelligence' of an IN is located. After processing a call, the SCP returns a telephone number to the SSP, referred to as the C-number. This is the telephone number to which the caller will finally be connected. The SSP then connects the caller to the number just like a normal PSTN call. Also see SCP. ST Signalling Terminal or Signal Terminal (SS7 term) Every Signalling Link (SL) consists of a Signalling Data Link (SDL) and an ST. The ST is the connection for the physical link to the exchange. It is defined by the level 2 function of the MTP. Also see MTP, STM. STL Standard Template Library STL provides a set of easily composable C++ container classes and generic algorithms (template functions) such as: - Vectors, lists, deques, sets, multisets, maps, multimaps, stacks, queues and priority queues. - Algorithms, for the most common kinds of data manipulations such as searching, sorting, merging, copying and transforming. In TelORB, two different implementations of STL are provided, one for Linux and one for Dicos. This is due to the quite different limitations concerning exceptions in the two environments. - STL for Dicos is provided in SWI/D279 - STL for Linux is provided implicitly and can be used without further `Uses relationship' to SWIs. STM Signalling Traffic Management (SS7 term) STM functions are part of the Signalling Network Management Functions for level 3 of the MTP. The STM functions control the diversion and reduction of traffic in the event of an SL or signalling route failure. STM controls and distributes the flow of traffic over the signalling routes. STM is responsible for the diversion and reduction of traffic in the event of a Signalling Link (SL) or Signalling Route failure. There are three STM functions: - Changeover: Traffic diversion to an alternative link is implemented by the changeover procedure. Changeover is a handshaking procedure which ensures that: - SUs are not lost - SUs are not duplicated - the correct SU sequence is maintained E.g. if SL 0 between SP A and SP B develops a fault, traffic can be diverted to SL 1 using the changeover procedure. Changeover begins by stopping transmission on the faulty link. Each SP contains a retransmission buffer which stores the transmitted signalling message until they are acknowledged. The retransmission buffers are cleared of all correctly received MSUs by exchanging ChangeOver Order (COO) and ChangeOver Acknowledgement (COA) messages. Both the COO and the COA SUs contain: - the routing label (Contains DPC, OPC, and SLC. It is used to identify the unavailable SL. The SLC identifies a particular SL within an LS.) - heading codes (The heading codes H1 and H0 indicate the type of SU, whether it is a COO or a COA.) - the Forward Sequence Number (FSN) (The FSN of the last SU accepted on the faulty link.) - Changeback: In situations where traffic has been diverted to an alternative link (SL), once the usual link becomes available again, the changeback procedure is initiated. In the changeback procedure SP A prevents the traffic concerned from being sent to SP B via the alternative route, and also begins transmission on the original route by means of the following procedures: - SP A sends a ChangeBack Declaration (CBD) over the alternative link (SL) - SP B replies with a ChangeBack Acknowledge (CBA) Traffic then resumes on the usual link. - Emergency changeover: Faults in an ST may make it impossible for the SP to determine the last correctly received MSU. When this happens, the Emergency ChangeOver (ECO) procedure is executed. E.g. when SP A detects a fault in e.g. ST 0 in SP A, it sends an Emergency Changeover Order (ECO) to SP B, to direct the signalling traffic to SL 1 (previously SL 0 was used). The ECO SU does not contain the sequence number of the last SU received from SP B. SP B replies to the ECO by sending a ChangeOver Acknowledgement (COA) to SP A. On receiving the COA, SP A will update its retransmission buffer for ST 0. SP A will then transfer the SUs in the retransmission and transmission buffers in ST 0 to ST 1. ST 1 will then arrange for the sending of these SUs to SP B via SL 1. Normal signalling traffic will then continue on SL 1. Similarly, if ST 0 in SP B was also faulty, SP B would respond to ECO with an Emergency Changeover Acknowledgement (ECA). Also see MTP, Rerouting. STP Signalling Transfer Point (SS7 term) An STP is an SP which transfers messages from one SP to another without processing them. Also see SP, LS, SS7, SS7 network, SRM, IN. IN explanation: One of the main components of IN. In INs the STP offers an alternative pathway for messages between the SCP and the SSP. The STP is in fact a node within the C7 signalling network and is not specific to IN. The STP switches the C7 signalling messages between the SCP and the SSP. Note however, that the SSP and SCP may exchange information directly without the information passing through the STP. Also see IN, SCP, SSP. STS Software Terminal Server (TelORB term) STS makes it possible to get log printouts from each of the TelORB processors as well as providing TelORB processor consoles where printouts from each of the TelORB processors can be seen as they happen. SU Signal Unit (SS7 term) SS7 signalling messages are transferred as SUs and are sent from one SP to another. Signalling messages are packed into standard format SUs by the MTP and are transferred on to an SL for transmission. SUs contain the information required for the signalling network to function. There are 3 SU (message) types, namely Message Signal Units (MSUs), Link Status Signal Units (LSSUs), Fill In Signal Units (FISUs). For more info about these SU types, see each acronym in this glossary. Each SU is made up of fields which have a specific function and some of these fields are common to all SU types. These common fields include - Flag (F): Indicates the beginning and end of an SU, i.e. delimitation. The bit pattern of the flags in the SU is 01111110. Flags go through a process of bit stuffing to prevent this bit sequence being imitated within the SU. At the transmitting SP, a '0' is inserted after each five consecutive '1's and at the receiving SP this '0' is removed. - ChecKsum bits (CK): Used for the detection of errors in the transmitted messages. See error detection below. - Length Indicator (LI): Distinguishes between the three SU types as follows: - LI of an FISU has the value 0. The FISU is responsible for maintaining link continuity and acknowledging received MSUs when no other MSUs are being sent. - LI of an LSSU has the value 1 or 2. The LSSU is responsible for indicating a change in link status and for indicating the length of the Status Field (SF). SFs are only found in LSSUs. The SF of an LSSU indicates a change in status of an SL. Depending on the status of the SL, different LSSUs are sent between SPs. There are 6 different Status Indications which indicate the change in status of the LSSU: - Processor Outage (PO) (SIPO): The processor (for SP) controlling an SL goes out of service. SF of LSSU = PO. LSSU type = Status Indication Processor Outage (SIPO). - Busy (B) (SIB): When an SL is busy and cannot transmit all the required SUs, an LSSU is sent to indicate this. SL with too many SUs to send. SF of LSSU = B. LSSU type = SIB. - Out of Service (OS) (SIOS): SL out of service. SL not in operation. SF of LSSU = OS. LSSU type = SIOS. - Emergency alignment (E) (SIE): When an SL is being brought into service it must be aligned. There are two methods of alignment: - Normal alignment and Emergency alignment. Emergency alignment takes place when an SL is required without delay. SL prepared in a hurry for immediate use. SF of LSSU = E. LSSU type = SIE. - Out of alignment (O) (SIO): An SL goes out of alignment. Something wrong with an SL. SF of LSSU = O. LSSU type = SIO. - Normal alignment (N) (SIN): When an SL is being brought into service it must be aligned. There are two methods of alignment: - Normal alignment and Emergency alignment. SL prepared for use. SF of LSSU = N. LSSU type = SIN. - LI of an MSU has the value > 2. The MSU is responsible for conveying information relating to the control of calls and conveying information on the status of the signalling network. The LI also indicates the length of the Signal Information Field (SIF) and the Service Information Octet (SIO). SIFs and SIOs are only found in MSUs. Signalling messages are packed into MSUs in the MTP. The SIO consists of the Service Indicator (SI) which indicates where the signalling messages are generated, e.g. SI=0100 indicates TUP, and the SubService Field (SSF). The SIO (SSF) contains the Network Indicator (NI) bit (NI = 2-bit code) and is used to discriminate between: - national and international signalling networks - two different national signalling networks - different level 4 parts (?) The NI tells the discrimination function how to interpret the label which contains the DPC. When an incoming SU arrives, the NI is examined first, followed by the DPC. The DPC is then compared to the point code of the SP. (Each SP in a network has its own unique point code.) If the DPC and SP's own point code differ, the message is sent to the routing function for transmission to another SP. If the DPC of the incoming message is equal to the point code of the SP, the message is handed on to the distribution function. Within an SP the message can be for a particular User or Application Part (UP or AP) or for the network management functions. The Service Indicator (SI) in the SIO indicates where the message will be sent. In the case of a user message the SI indicates to which UP the message will be sent. The SIF consists of: - the data, which is generated by the UPs, APs or network management functions - the heading codes, H0 and H1, which are used to identify different MSUs - the label, which is used to route messages. The label part of the SIF contains: - Circuit Identification Code (CIC): Contains the number of the speech or data circuit to which the MSU pertains. - Signalling Link Code (SLC): Identifies the SL to which the MSU refers. SLCs are only used on signalling messages generated by the network management functions (level 3 of the MTP). - Signalling Link Selection (SLS): Selects one of the SLs from an LS. - Originating Point Code (OPC): Contains the Point code for the SP where the MSU has originated. - Destination Point Code (DPC): Contains the Point code for the SP where the MSU is destined. The MTP message handling functions use the routing label in the SIF to determine where to route the message. The routing label of a user message consists of the OPC, DPC and the SLS. The routing label of a network management message contains the OPC, DPC and the SLC. It is the SLS/SLC field which indicates a particular SL to carry the message. The SLS and the SLC perform the same function for their respective message types. The SLS/SLC field is used for: - load sharing between SLs - load sharing between LSs Bit 0 in the SLS/SLC field determines the link used for transmission of an SU. SLs are assigned on the basis of the value in bits 0 to 3 of the SLS. There are two methods of load sharing between LSs where bits 1 and 2 of the SLS/SLC determine the method: - Messages are shared equally between LSs - Messages are directed towards a particular LS which is said to have priority. If that LS develops a fault, the SUs are directed to an alternative LS. - Forward Indicator Bit (FIB): Control errors in the transmission of SUs. Indicates whether a retransmission of SUs is ongoing. Will be toggled during SU retransmission to indicate to the receiving SP that this is a retransmission. - Forward Sequence Number (FSN): Control errors in the transmission of SUs. Indicates the number of the SU currently being sent (löpnummer). Sequence number of the SU being sent. SUs are transmitted in order of their FSN, e.g. first 34 and then 35. - Backward Indicator Bit (BIB): Control errors in the transmission of SUs. Indicates if there is a problem with one of the SUs sent. Will be toggled if there is an error. Will be unchanged if no error has been detected. Will be toggled during SU retransmission. - Backward Sequence Number (BSN): Control errors in the transmission of SUs. Acknowledges the last error free SU sent from the SP now being contacted. Sequence number of the SU being acknowledged. Negative acknowledgement is performed by setting the BSN to the number of the last correctly received MSU and toggling the BIB bit from either 0 to 1 or from 1 to 0 and send the SU to the sending SP (SP A). On reception of this negative acknowledgement, SP A must retransmit all SUs that have been sent to SP B since the last correctly SU was received (in the same order). This is done before any new SUs are sent. Errors are detected using the CK bits in the SU. Errors are corrected by retransmitting messages which were faulty using the FSN, BSN, FIB and BIB fields of an SU. Summary of the structure of the three SU types: - FISU: F, CK, FISU LI=0, FIB, FSN, BIB, BSN, F. - LSSU: F, CK, SF, LSSU LI=1 or 2, FIB, FSN, BIB, BSN, F. - MSU: F, CK, SIO, SIF, MSU LI>2, FIB, FSN, BIB, BSN, F. Alignment: The two error rate monitors used to determine loss of SL alignment are: - Signal Unit Error rate Monitor (SUERM): Incremented when a faulty message is received. This occurs when more than seven consecutive '1's are received or when a certain maximum length of SU is received. The SUERM is used while the link is in service. - Alignment Error Rate Monitor (AERM): Similarly incremented as SUERM while the link is being aligned. Loss of alignment will occur when the SUERM or AERM exceeds a certain predefined level. Initial alignment is a level 2 function which occurs when: - an SL is first brought into service - an SL which has been out of service is brought back into service or is restored. The SL management function of level 3 decides to use normal or emergency alignment depending on how urgently the SL is required. The AERM is then incremented if a faulty message is received during link alignment. Note that it is LSSUs which are sent between the two SPs during the initial alignment. The following LSSU types are sent during initial alignment: SIOS after initial power up of the SL, SIO at beginning of align- ment to start the alignment procedure, SIN for a period of 8 seconds during normal alignment, SIE during emergency alignments for a 0.5 second proving period. The error rate of the SINs and SIEs is checked by examining the CK bits and incrementing the alignment error rate monitor if an error is detected. Level 2 of the MTP is concerned with delimitation (flags, see flags above) and alignment (see alignment above). Error detection and correction: The error detection function of level 2 of the MTP is used to detect errors in an SU. The CK field of an SU contains 16 checksum bits which are generated in level 2 (MTP) and are used for error detection. The CK bits are assigned a value based on the preceding bits of the SU. The SU is then sent on the SL, where at the receiving SP the CK bits are compared with the preceding bits of the SU. If they do not correspond, the SU will be discarded and the SUERM incremented. With the basic error correction method an SU that is transmitted is stored in the buffer of the sending SP (SP A), until it is acknowledged. If no error is found at the receiving SP (SP B), the receiving SP (SP B) positively acknowledges the SU in its next SU that is sent to the sending SP (SP A). SP A can then clear the data about the sent SU from its transmission buffer. Signalling messages are received by the MTP (the message handling functions part of the MTP) from UPs, APs and MTP's own network management functions. SUs are transferred from level 3 of the MTP onto the Signalling Link (SL). SUs are also sent from level 2, e.g. to indicate status changes on the SL. Incoming SUs may be distributed by the MTP to either a specific UP or AP, or to MTP's own network management functions. The SU is mentioned in the explanation of most of the SS7 terms in this glossary. Subfield SS7 information generated by the user is divided into subfields. There are 4 types of subfield, namely mandatory, optional, fixed length and variable length. Subnetmask The subnetmask states where the border between the Net and hostid (Local Address) is in an IP address. The subnetmask + the IP address states which logical net the receiver (host) is located on. Used in e.g. routers where the router gets an IP address and uses the subnetmask to find out which logical net the receiver is located in. Class A address: First bit = 0 | Net(7 bits) | Local Address(24 bits) Subnetmask=255.0.0.0 0-127 Class B address: First bits = 1 0 | Net(14 bits) | Local Address(16 bits) Subnetmask=255.255.0.0 128-191 Class C address: First bits = 1 1 0 | Net(21 bits) | Local Address(8 bits) Subnetmask=255.255.255.0 192-223 255 unique addresses in a class C address. Class D and E for special purposes, e.g. experimental. Subnetting = Split a net into several subnets by moving the subnetmask to the right. Also see Router. SUNET Swedish University NETwork Supplementary service A supplementary service is a service which is an optional add-on to a basic service, e.g. in telephony you can have supplementary services such as abbreviated dialling and freephone numbers. SVCD Super Video Compact Disc As VCD, but with a better quality. SWI SoftWare Interface (TelORB term) Contains Delos and IDL specifications of objects. SWILib SWI Library. Container of SWIs. (TelORB term) |
| T | Top of Glossary |
TADE TSP Application Development Environment (TelORB term)
TADE is an environment for Application Designers who
build applications on the TSP Platform.
TADE offers Solaris and Linux as platforms when
designing applications.
TADE's SDK supports Solaris/Linux, and some of the TADE
Optional tools support Win/NT via the GUI as well.
TADE components:
SDK (TADE, Mandatory Tools)
TADE Optional Tools
APIs (Descriptions)
User Manuals (Design Patterns, Guide Lines, Design
Rules etc)
Also see TADE's home page.
TB Test Bed (TelORB term)
The deliveries from the design department is integrated
into a test bed on which testing (function and system
tests) is performed before release.
TC Test case (TelORB verification term)
TC Transaction Capabilities (SS7 term) (Part of AP)
TC was added to SS7 to enable the transfer of
information between distributed nodes in a network.
TC was designed in accordance with the OSI model in
order to provide generic services to applications while
being independent of them.
TC is a protocol that is used in conjunction with the
MTP to support the transfer of non-circuit related
messages.
TC is further divided into:
- TCAP, which directly accesses the services of the
SCCP.
- ISP, which in SS7 is a null layer.
(TC = TCAP and ISP)
The purpose of TC is to provide the means to establish
non-circuit related communication between nodes and to
provide generic services to applications.
TC was added to the SS7 signalling system to provide for
the non circuit-circuit related and interactive transfer
of information across the network. The ITU-T has defined
that the overall objective of TC is to provide the means
for the transfer of information between nodes and to
provide generic services to applications while being
independent of any of these.
In the original specification for SS7, all of the
network transfer requirements were provided by MTP/SCCP.
TC's introduction allows application functioning and
protocols to reside in the TC-users (e.g. MAP, INAP,
OMAP) while functions and protocols common to all
applications reside in TC. (See ASCII picture at SS7.)
TC was designed to be application independent, serving
the need of all applications (including those not
specified) while at the same time remaining independent
of these applications. In this way, TC can be contrasted
to the TUP and ISUP which were specified to support
particular applications. TC-users now interface with
MTP/SCCP via TC.
TCs are implemented by (TCs are made up of):
- The TCAP (OSI layer 7).
- The ISP (which provides the services of OSI layers 4,
5 and 6. The ISP is not yet present in SS7
implementations.
The TCAP layer directly accesses the service primitives
provided by the SCCP. (Because TC is confined to using
connectionless transactions, the services of the ISP are
not required and the TCAP interfaces directly with the
SCCP.)
Note that the ITU-T uses the terms TC and TCAP inter-
changeably.
Applications which use TC can be classifies into these
categories:
- Real-time sensitive, e.g. checking subscriber location
in the mobile network.
- Less real-time sensitive, e.g. downloading customer
billing information.
TC is independent of the applications that wish to use
it.
The following applications are TC-users:
- Mobile radio applications, e.g. location registration.
The PLMN uses the TC of the SS7 signalling network to
access information from different points in the
network. E.g. an MSC may need to obtain MS location
information from a database located in a different
node. Each node in the mobile network has an MAP which
defines the protocol for mobile signalling over the
SS7 network.
- Access to specialized nodes, such as SSP and SCP in
IN.
The INAP generates signalling for the IN. The SSP can
access special routing information from an SCP over
the SS7 network.
- Operation amd maintenance applications, e.g. bulk data
transfer.
An OMC will interface with SS7 through the OMAP. The
OMC will have access to any node within the network to
invoke remote operations, e.g. remote testing, and
collection of information such as statistics.
- Registration, activation and invocation of
supplementary services.
An association between TC-users exchanging components is
called a dialogue.
An association between TC-providers (e.g.TCAP) is called
a transaction.
Transactions are performed by exchanging messages over
the signalling network (e.g. between TCs in different
nodes). Signalling messages passed during a transaction
are non-circuit related.
Also see CHA, Connectionless service, CSL, DHA,
Dialogue, INAP, MAP, Non circuit-related signalling,
OMC, PLMN, SCCP, SS7, TCAP.
TCAP Transaction Capabilities Application Part (SS7 term) (Part of AP)
TCAP directly interfaces with the APs and allows data
interchange between applications without a direct
connection.
TCAP allows interactive network-wide signalling
communication between APs.
TCAP and ISP enable the introduction of interactive
network-wide signalling communication as used in mobile
networks. (TCAP and ISP = TC)
APs that use TCAP are, e.g. MAP and OMAP.
For applications which require a connectionless service,
the ISP is not needed and the TCAP interfaces directly
with the SCCP.
For connection-oriented services, the TCAP requires the
services of the ISP. So far, the ITU-T have only defined
connectionless services. The connection-oriented
services are for further study.
The TCAP is divided into the two sub-layers:
- CSL (Component Sub-Layer)
- TSL (Transaction Sub-Layer)
See these acronyms separately.
Messages sent by TCAP currently use only the connection-
less procedure of the SCCP. TCAP messages are embedded
in SCCP Unitdata (UDT) messages and transferred to the
MTP. In the MTP, UDT messages are embedded in the SIF of
the MSU for reliable transfer through the network.
Any particular application may require the invokation of
one or more remote operations. This will involve the
exchange of messages between TC-users (in different
nodes). An association between two TC-users exchanging
components in order to perform an application is
referred to as a Dialogue (see CSL). There may be a
number of Dialogues between TC-users at the same time.
Each is given a unique value by the TCAP.
To invoke an operation, the TC-user sends a primitive to
the CSL (in own node) with parameters including:
- the operation requested
- the class of operation requested
In the CSL, this is mapped onto a component with the
mandatory fields:
- an operation code (identifies the operation being
invoked)
- parameters (values (data) associated with that
operation)
Other fields may be e.g.:
- an Invoke ID (identifies the particular invokation)
- an Transaction ID (identifies the transaction invoked)
- Component
- Length
- Type
The TSL is reponsible for exchanging these components in
messages between TCAPs (in different nodes). The
association established between the two TSLs
(TC-providers) (in different nodes) is referred to as a
transaction. A dialogue between TC-users (in different
nodes) involves a transaction between TCAPs (in
different nodes). Two TC-users (in different nodes) may
support a number of applications at the same time. This
will involve the establishment of a number of dialogues.
Each dialogue is identified by a Dialogue ID. Each
corresponding transaction is given a transaction ID. The
dialogue IDs are mapped onto the transaction IDs.
When a TC-user invokes a number of operations, multiple
dialogues are set up with the remote TC-users.
As well as the possibility of having multiple dialogues
between two TC-users, it is also possible that the same
operation may be invoked by different applications
running running at the same time.
A TCAP message consists of:
- A message (type) tag, which indicates the message
type, see below.
- A message length, which indicates the total length of
the message. The length is given in octets. This
length is limited by the MTP in the connectionless
service.
- A message contents, which contains the body of the
message. The message contents field contains the IEs
of the message, see below.
The message contents of a TCAP message may consist of a
number of Information Elements (IEs).
Each IE has the same structure as the message itself,
this structure consists of:
- Tag, which distinguishes between one type of
IE and another.
- Length, which specifies the length of the contents.
- Contents, which contains the substance of the element,
the information to be conveyed.
The contents of an IE may itself contain one of more
IEs. If the message contents field consists of a single
value, the IE is called a primitive (this is different
to an OSI primitive). If the message contents field
contains one or more IEs, then the `parent' element is
called a constructor. The `IEs within IEs' format is
very flexible and allows TCAP to support several
applications.
The message contents field of a TCAP message contains a
transaction portion IE and a component portion IE:
- The component portion of the message contains
information regarding the particular invocation
(Invoke ID), the operation being invoked (Operation)
and the parameters associated with the component
(Parameters).
It is of relevance to the CSL.
- The transaction portion of the message contains
information regarding the transaction identification
(Transaction ID) and the message type (Message type
code) and is of relevance to the TSL.
The message type tag indicates that the message is one
of the following types: Unidirectional, Begin, Continue,
End or Abort.
Depending on the message type, the transaction portion
IE contains:
- a transaction ID tag, which can be either an
originating transaction ID tag or a destination
transaction ID tag.
- the transaction ID length.
- the transaction ID.
The originating transaction ID is assigned by the node
sending the message and is used to identify the
transaction at that end (node).
The destination transaction ID identifies the
transaction at the receiving end (node).
When present in a TCAP message, the component portion
contains one or more components. Each component has:
- a component type tag, which indivates the type of
component (e.g. invoke).
- a component length, which indicates the length of the
component.
- the operation code IE, which specifies the operation
to be carried out. This is interpreted by the TC-user.
- the invoke ID IE, which uniquely identifies a request
for an operation. It is used to correlate requests and
responses.
Other elements in the component are:
- optional parameters, which contain data associated
with the component.
Also, depending on the component type, it may have:
- an error IE to indicate why an operation cannot be
completed successfully (Return error).
- a problem IE to indicate why a component is rejected
(Reject).
5 types of components can be included in TCAP messages
to invoke operations and receive replies. These are:
- Invoke: Requests an action or information from a
remote end (other node). (Fields not explained
here.)
- Return result last (Result-L): Reports the successful
completion of an operation. It contain the last or
only segment of a result.
- Return result not last (Result-NL): Sent if the reply
has to be segmented. In this case all segments
except the last are contained in this component
type. The last segment is contained in a Result-L).
(Fields not explained here.)
- Return error: Indicates that the operation was not
successfully completed. (Fields not explained here.)
- Reject: Indicates that a component was received and
rejected. (Fields not explained here.)
Each field in a component has an associated tag and
length.
Also see TC, ISP, CSL, TSL, AP, MAP, OMAP.
TCP Transmission Control Protocol (IN term)
TCP/IP Transmission Control Protocol/Internet Protocol (IN term)
or Transmission Control Protocol on IP.
Some base functionality of TCP/IP are telnet, FTP and
SMTP.
OSI TCP/IP
----------------------------- --------------------
- Layer 7: Application Layer Application
- Layer 6: Presentation Layer Application
- Layer 5: Session Layer Application
- Layer 4: Transport Layer Transport
- Layer 3: Network Layer Network
- Layer 2: Data Link Layer Data Link
- Layer 1: Physical Layer Data Link
TC-user Transaction Capabilities user
An application part (AP) that uses TC.
See TC.
TDM Time Division Multiplexing
TDMA Time Division Multiple Access
Name of products and services based on the
TIA/EIA 136 standard.
Telecom Grade What we have when a system is designed to meet very high
demands for robustness and performance, that is, when it
has real-time characteristics and meets EMC demands, and
when it can run almost continuously, without going down
for more than approximately five minutes per year (ISP
99.999%).
Televoting Example of an IN service.
The televoting service is used by television viewers or
radio listeners when they wish to phone in and give
their opinion on a particular issue.
Teleservice A teleservice is a complete communications service which
includes all aspects of communication between users,
e.g. telephony, telex and fax.
telnet Teletype Network (TCP/IP base application)
TelORB TelORB includes a so called ORB implementing the IIOP, hence
the name TelORB.
TelORB is an operating system developed at Ericsson for
standard hardware (Sparc or Pentium based processor
boards, etc.) and standard programming languages (C++
and Java) for fault-tolerant telecom applications.
It is a distributed operating system with an object-
oriented database (also distributed) in primary memory
showing a linear capacity growth. TelORB is e.g. used
for home location registers (HLRs) in GSM networks
serving several million subscribers.
TelORB
processor Traffic processor, i.e. one of many processors where
"traffic" is executing. Compare with IO processor.
Terminating
exchange The terminating exchange is the exchange to which the
B or called customer (subscriber) is connected.
TFP Transfer Prohibited (SS7 term)
The Transfer Prohibited Procedures are defined by the
SRM functions of level 3 of the MTP. When a Signalling
Route becomes unavailable the Transfer Prohibited
Procedure is implemented and a TFP message is sent.
The TFP procedure is performed at an STP when it has
to notify some adjacent SPs and STPs not to route SUs
for a given Destination Point (DP) (read SP) through
the STP.
Forced rerouting is used when a Signalling Route
becomes unavailable. All traffic is stored in a forced
rerouting buffer.
The format of a TFP message looks as follows:
- Destination (Contains the identity of the SP to
which the message refers.)
(In the case of the TFP being sent from
STP B to SP C, the destination identifies
e.g. SP D as being unavailable through
STP B.)
- H1 (The heading code H1=0001 identifies the message
as a TFP message.)
- H0 (The heading code H0=0100 indicates that this is
either a transfer prohibited, restricted, or
allowed message.)
- Label (Contains the OPC, DPC and SLC.)
Also see STM, LS.
TFTP Trivial File Transfer Protocol
TFTP is used to transfer files between hosts. In TelORB
TFTP is used when a TelORB processor is started. The
TelORB processor is communicating with an IO processor
via DHCP to receive some initial data. Thereafter, TFTP
is used to transfer some initial files to the loading
TelORB processors, normally TelORB processors 1 and 2.
When these files are started in the traffic processors,
the communication to the IO processors is switched from
TFTP to the file system. The file system uses the
DUCK-server and FileServerInterpreter functions.
(Source: "Installation Test Instruction" / "Preparing
IO processor 1", rev PA1 by Andreas Johansson)
TG Traffic Generator
A tool for simulating telephony traffic.
Thread Threads are used to allow you to design on a high level to
coordinate the execution (activities) within a process
(like a flowchart). A manager of what to do, based on
results from activities ordered by the thread. Only use
threads when needed for complex situations.
TMN Telecommunications Management Network (IN term)
TP TelORB Processor or Traffic Processor (TelORB term)
TPS Transactions Per Second
Transaction An association between two TCAPs. (SS7 term)
The association between two communicating TSLs (part of
TCAP) (in different nodes) is called a transaction.
Also see TSL, TCAP.
Transport
Layer The Transport Layer (layer 4 of the OSI model) guarantees
that the bearer service has the quality required by the
application in question. Functions performed by the
transport layer include error detection and correction
and flow control.
This layer guarantees the quality required by an
application.
It provides error detection and correction (end-to-end),
flow control and sequencing.
The Transport Layer isolates the layers above so that
they are not affected by the characteristics of the
network.
It optimises the communication by multiplexing or
splitting data streams before they reach the network.
Also see OSI.
Triggering Triggering involves looking up trigger table data in
order to identify calls requiring IN access. (IN term)
TSC Transit Service Center (IN term)
TSL Transaction Sub-Layer (SS7 term)
The TSL is one of the two parts of the TCAP. The other
part of TCAP is CSL.
The TSL is responsible for managing the exchange of
messages between TC-users.
The TSL manages associations (transactions) between
TC-providers and handles the exchange of messages
between TCAPs (in different nodes).
The TSL provides the capability to send messages between
peer TCAPs (i.e. TCAPs in different nodes), i.e. the TCL
is responsible for managing the exchange of messages,
containing components (from CSL) between TC-users.
The TSL receives components from the CSL, packages them
into messages and passes them to the SCCP for transfer
to the remote node (via MTP). The association between
two communicating TSLs is called a transaction.
The TSL:
- manages associations (transactions) between
TC-providers.
- handles the exchange of messages between TCAPs.
5 types of messages are defined for the TSL to handle
structured and unstructured dialogues:
- Unidirectional: A Unidirectional message is sent in an
unstructured dialogue between TC-users (in different
nodes). No association (transaction) is established
between the TC-providers.
- Begin: A Begin message is sent to start a structured
dialogue between TC-users. A transaction is
initiated between TC-providers.
- Continue: A Continue message is sent to continue a
structured dialogue between TC-users. The
establishment of a transaction between TC-providers
is completed and is continuing.
- End: An End message is sent to terminate a structured
dialogue between TC-users. The transaction with the
peer TC-provider is ended.
- Abort: An Abort message is sent to abort a structured
dialogue between TC-users. The transaction between
TC-providers is aborted.
Also see TCAP, CSL, TC.
TS-HOD Two-Step High-Ohmic Distribution
TSP ? Server Platform
I interpret the T in TSP as TelORB. I also heard that
TSP is not an acronym, but a name. Please give me
feedback on this. I work with TSP, but I don't know what
it stands for - embarrasing, but no one else seems to
know either.
TTL Time To Live
Part of IP header in in IP (protocol)
TUP Telephone User Part (SS7 term)
The TUP is that part of a telephone exchange which uses
the SS7 signalling system to control telephone calls
and circuits.
The TUP generates messages for the control of circuit-
related PSTN activities, e.g. the set-up and release of
PSTN calls.
SS7 is e.g. used in PSTNs to improve the speed and
efficiency of the telephone service. The TUP is the
functional part of the SS7 node which defines the
necessary signalling functions for setting up,
supervising and clearing calls in the PSTN.
The TUP is one kind of a UP in an SS7 SP.
TUPs in different exchanges control telephone calls
by sending messages over the (SS7) signalling network.
The TUP controls telephony activities using several
different TUP messages. These messages are classified
into groups according to the activities they perform.
There are approximately 60 TUP messages in all. These
are divided into 9 TUP message groups as follows (also
see further down):
- Call set-up: 5 groups
(FAM,FSM,BSM,SBM,UBM)
- Call supervision: 1 group
(CSM)
- Circuit maintenance and supervision: 2 groups
(CCM,GRM)
- Node to node communication: 1 group
(NNM)
The most frequently used group of messages is the
Forward Address Message (FAM) group. This group is
associated with the set-up part of a telephony call.
These messages contain the telephone number (known as
the address) of the subscriber that the caller wishes
to contact. These messages are sent forward from the
originating TUP (exchange) to the destination TUP
(exchange).
The Successful Backward set-up Message (SBM) group is
also used during call set-up. Messages in this SBM
group are generated by the destination exchange and
sent back to the originating exchange when a call
succeeds. Hence the name SBM.
The part of the MSU in which the TUP information is
stored is called the Signalling Information Field
(SIF). It contains:
- The label, indicating the origin and destination of
the message and the circuit (such as the speech
circuit) to which the message refers, i.e.:
- the Destination Point Code (DPC) which is a
number indicating the destination of the message
- the Originating Point Code (OPC) which is a number
indicating the origin of the message
- the Circuit Identification Code (CIC) which
identifies the speech or data circuit to which the
message refers between the destination and origin.
The DPC and OPC identify the terminating and
originating telephone exchanges, and the CIC
identifies the circuit between them.
For international exchanges, point codes are
allocated by international agreement. Point codes
within a country are assigned by the local
administration.
For an incoming message, the OPC and CIC are used
as pointers in a look-up table. Taken together,
they indicate the exact telephone route and circuit
referred to in the message.
When, on the other hand, the TUP wishes to generate
a message, it uses the telephone route and circuit
identities to point out the correct DPC and CIC.
These are then placed in the outgoing message.
- The heading codes, which indicate the type of
message being sent (received) and the message group
to which the message belongs. H0 indicates the
message group and H1 indicates the message within
that group, i.e. the message type.
The 9 message groups are as follows:
- Forward Address Messages group (FAM): H0=1
- Forward Set-Up Messages group (FSM): H0=2
- Backward Set-Up Request Messages group (BSM): H0=3
- Successful Backward Set-Up Messages group (SBM): H0=4
- Unsuccessful Backward Set-Up Messages group UBM): H0=5
- Call Supervision Messages group (CSM): H0=6
- Circuit Supervision Messages group (CCM): H0=7
- Circuit Group Supervision Messages group (GRM): H0=8
- Node to Node Messages group (NNM): H0=9
Example of H1: H1=1 => Initial Address Message.
- The data, which contains a number of subfields with
information such as the calling address and the
called addresses. The data field can vary in length
from zero to tens of bytes, depending on the amount
of information in the message. This data area is
optional. When used, it can contain information
such as the B-subscriber's number. The data field
contains a number of subfields where each subfield
carries an important piece of telephony information
such as the category of the calling subscriber.
For IAM: The Calling Party Category subfield (CPC)
specifies e.g. the customer type and the
language used by the operator.
The "Message indicator" subfield specifies
the call type and its requirements.
There are more subfields, e.g. "Number of
address signals" which specifies the length
of the next subfield containing the
B-subscriber-number (Address signals).
E.g. the TUP in exchange A wishes to send a message
to the TUP in exchange B. The TUP in exchange A
generates the core of the message and passes it on to
the MTP. The first and last segments of the message
are generated by the MTP and are added to the centre
piece or core of the message to ensure reliable
transmission. This centre piece or core of the message
contains the information generated in the TUP and is
called the SIF. The message is transmitted to the
destination exchange. When the TUP message arrives at
the destination exchange, the receiving MTP processes
and removes the MTP-generated information and passes
the SIF to the receiving TUP.
The following describes how TUP messages establish a
successful telephony call between two subscribers:
The call is initiated when the A-subscriber lifts
the handset and dials the B-subscriber's number,
e.g. 23456.
The A exchange analyses the dialled digits and
selects a telephone circuit to the B-subscriber's
exchange.
The TUP in the A-subscriber's exchange now prepares
a message to initiate the call on that circuit.
This message is called an Initial Address Message
(IAM), from the FAM group. (IAM contains information
which helps in the efficient routing of a call, e.g.
the calling subscriber's category and type of
telephony path or circuit required.)
IAM contains the dialled digits and the
A-subscriber's category, e.g. ordinary subscriber.
It also contains information which will help
subsequent exchanges to route the call efficiently,
e.g. if the call has special priority.
The CIC subfield in the label of the IAM is used to
inform exchange B which circuit exchange A wishes to
select for speech.
Normally, the A exchange will wait until all digits
are received from the calling subscriber before
generating the IAM.
The IAM will then contain the complete
B-subscriber's number.
In the case where the IAM message does not carry the
subscriber's complete address, the remainder of the
digits will be in Subsequent Address Messages (SAM).
SAM is also a member of the FAM message group.
When the address is received in the B exchange, it
is analysed and the required B-subscriber is
identified.
The B-subscriber's line is checked to see if it is
free and working.
If the call can proceed, the B exchange's TUP sends
an Address Complete Message (ACM) from the SBM group.
The speech path is now established.
A ringing current is sent to the B-subscriber and a
ring-back tone is sent to the A-subscriber's phone.
From the subscriber's point of view, as soon as the
number is dialled, a ring-back tone is heard almost
instantaneously, because of the speed of the message
interchange.
At this stage of the call, the A exchange is
awaiting the B-subscriber's answer.
No further messages are exchanged until that answer
is forthcoming.
When the B-subscriber answers, an answer message is
generated in the B exchange TUP.
This could be either Answer Signal Charge (ANC) or
Answer Signal No Charge (ANN).
In the case of a normal call, the ANC message is
received in the A-subscriber's exchange. If the call
were to a "Freephone" number with no charge, the ANN
message would be sent.
These messages are from the CSM group. If charging
is required, it commences after the ANC message is
received in the A-subscriber's exchange. No further
messages are exchanged until the call is over.
Now the A-subscriber hangs up.
A Clear Forward signal (CLF) from the CSM group is
generated at the A exchange TUP.
The B-subscriber's exchange responds with a Clear
Back message (CBK) also from the CSM group.
On receipt of the CBK, the A exchange responses with
a Release Guard message (RLG) after it has released
its equipment (circuit).
When the RLG is recognized by the B-subscriber's
exchange, it makes the outgoing circuit available
once again for traffic.
The following describes how TUP messages establish an
unsuccessful telephony call between two subscribers:
As with the successful call, the IAM begins with all
the necessary digits to select the B-subscriber.
If the B-subscriber is already on a call, the
message Subscriber Busy (SSB) from the UBM group
will be generated.
Some other messages which may be sent back in the
event of an unsuccessful call are:
- Line Out of Service (LOS)
- Unallocated National Number (UNN)
- Access Barred (ACB)
On receipt of any of the messages from the UBM group,
the A exchange will clear the call with a Clear
Forward (CLF) message.
During call set-up, it may be necessary for the
B or intermediate exchanges to request extra
information from the A exchange.
The SS7 TUP provides a facility to do this by using
messages from the BSM and FSM groups.
E.g. the B-subscriber's exchange wishes to obtain
the number of the caller.
It will request this number using a General Request
Message (GRQ) from the BSM group.
The A exchange will respond with a General Forward
Set-Up Message (GSM), containing the A number, from
the FSM group.
The SS7 TUP has two message groups used for circuit
supervision and maintenance, namely:
- CCM: Contains messages for individual circuits.
The CCM group includes messages such as:
- Blocking (BLO)
- Blocking Acknowledge (BLA)
- Unblocking (UBL)
- Reset Circuit (RSC)
E.g. a circuit develops a fault. The TUP in one
of the connected exchanges will send a BLO
message to the other connected exchange. This
message will specify the circuit to be blocked.
The distant exchange's TUP will respond with a
BLA message. To unblock the circuit, UBL and UBA
messages are exchanged. Since many telephony
circuits consist of multi-channel PCM links and
since line and hardware faults on such circuits
would cause multiple circuit failures, the TUP
can also send circuit group messages.
- GRM: The GRM group includes messages such as:
- Maintenance Group Blocking Message (MGB)
- Maintenance Group Blocking Acknowledgement
(MBA)
- Circuit Group Reset (GRS)
- Hardware Failure Blocking Acknowledgement (HBA)
- Hardware Failure Group Blocking Message (HGB)
(GRS spans over the other messages.)
An MGB initiates blocking of all the circuits on
a particular PCM link. This is acknowledged by an
MBA message.
Node to Node Messages (NNM) enable direct communication
to take place between the two end nodes of a call
(e.g. between two subscribers in exchange A and
exchange B).
Node to node messages are also known as end to end
messages. These messages are used to send information
or requests for information between the end nodes of a
call, or to perform an enquiry or collect data, so
that a call can be established. Calling Line Identity
(CLI) is an example of node to node message. This is
used to transfer the calling subscriber identity from
the originating exchange.
NNM may also be used to request and deliver data which
will help in the establishment of calls. These
messages are used to establish calls between members
of a Closed User Group (CUG). A CUG is a group of
subscribers with special access to or from the public
telephone network.
Information concerning the CUG and its subscribers can
be held in a central database. This central database
is interrogated when a CUG subscriber wishes to make a
call. This interrogation and the subsequent response
are carried out using NNM. The message groups used
are:
- Closed User Group Validation and Selection request
groups (CVS): CVS messages are sent from the
A-subscriber's exchange to the database. They
contain the identities of the called and calling
subscribers.
- Closed user Group Selection and Validation Response
Message group (CRM): CRM messages are returned from
the database to the A-subscriber's exchange and the
call set-up can proceed.
The format of each type of message (i.e. the arrangement
of the subfields) may vary depending on the TUP version.
For the exact format for each version of the TUP, refer
to the relevant information. Not all versions of the TUP
conform exactly with the ITU-T specifications
Q.721 - Q.725.
Also see GSM, UP, SU, SS7, ISUP, OMAP, ACM.
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| U | Top of Glossary |
UAN Universal Access Number (IN term) Example of an IN service. The UAN service allows service subscribers to have a single number for several different locations within a country. The service is mainly intended for companies that have more than one premises and want to be reached from anywhere in the country by dialling one special number, independent of area codes. The routing of the call will be dependent on factors such as the time, date and the location of the service user. As with the freephone service, the UAN has a special prefix, e.g. 1850, which the local exchange detects as a request for an IN service. UDC UNIX Database Client UDP/IP User Datagram Protocol on IP UDT Unit DaTa (SS7 term) The UDT is a message used by the SCCP when sending data in connectionless mode. Also see Connectionless service. Um-interface The Um-interface, also known as the Air-interface, is the interface (protocol) between the BTS and the MS in mobile networks. Same as LAPDm. Also see GSM, BTS, LAPDm, MS, Protocol, Air-interface. UMTS 3rd Generation Mobile Telephony System (currently called 3G) In Sweden, 4 licenses for UMTS-nets were provided in December 2000 to Tele2, Europolitan, Orange and Hi3G. UMTS is built up of the same technique as Internet. UP User Part (SS7 term) (Can be seen as protocols) The UP is that part of the SS7 node which generates messages and transfers them via the MTP. There are different types of UPs, e.g. the TUP which generates messages relating to the telephone service. The parts of the SS7 node that generate the signalling are called UPs. A UP generates, transfers and receives interexchange signalling messages, e.g. TUP messages and ISUP messages. AP | UP ------- MTP Examples of SS7 user parts: TUP, ISUP. The following UPs are used in GSM: - Telephony User Part (TUP): This UP is that part of a telephone exchange which uses the SS7 signalling system to control telephone calls and circuits. See TUP for further info. - ISDN User Part (ISUP): This is the UP of an ISDN exchange which generates messages to control ISDN calls and circuits. See ISUP for further info. Also see SS7, AP, MTP, TUP, ISUP, SU, MSU, SP, SI, SIO, SL, SLS, Distribution, Rerouting, Signalling message, GSM. UPT Universal Personal Telecommunications (IN term) Example of an IN service. The UPT service enables service users to be reached by the same number regardless of their location, e.g. at home or at work, based on parameters such as time-of-day. Service users can dial in and alter the parameters for this service as they wish. In other words, UPT provides mobility and roaming within fixed networks. UPT also allows users to determine how incoming calls are handled. E.g. it can facilitate the screening of non-priority calls or the use of voice mail. U-Qtil Probably Quick Utility (TelORB term) This abbreviation should probably be Q-Util instead of U-Qtil, but the letters U and Q changed positions. USB Universal Serial Bus User to user signalling The SS7 network supports this ISDN access service. The service enables subscribers to send messages through the network from their terminal without first setting up a speech connection. Also see SS7. USR User-to user (SS7 term) A user-to-user information (USR) message is used to transfer user-to-user data. UTRAN UMTS Terrestrial Radio Access Network Also see CPP. |
| V | Top of Glossary |
VCD Video Compact Disc VCD uses MPEG1 as its compressing format, which gives a quality which is a little bit better than VHS. To be compared with MP3. You can make a film in the VCD format and then "burn" it on a CD-R: Vega A TelORB simulated processor environment. It is a UNIX process with a "hardware" adaptation layer that makes it behave like an ordinary TelORB processor. Multiple Vega processes can be interconnected to verify distribution aspects. Vendor Vendors are responsible for IN resource provisioning and assisting the service provider in the area of operations and maintenance. Vendors develop IN service software, either new service logic or service management tools, to meet the requirements of service providers, service subscribers and service users. VIP Virtual Internet Protocol The VIP addressing possibility was introduced in TelORB in TelORB release R14. In the first phase, it was not possible to use VIP addressing between two geographical redundant TelORB nodes. In TelORB, the VIP scenario is where a TelORB zone is connected to an external network in such a way that the network only sees one IP address. In this case, all the external network should see is a number of connection points that it perceives as routers that are all able to forward IP packets to the same IP host. Node interconnection is done with a VIP addressing scheme that allows the node to be addressed by a single IP address representing a connection point. A node may however contain several such connection points. The interfacing routers will distribute incoming IP packets to TPs in a round robin or random way. Receiving TP may further distribute processing within the node. Geographical redundant TelORB nodes will use this solution in a symmetrical way. TelORB may also interface other cooperating non-TelORB nodes in the same way. Also see DIP, RIP. VLAN Virtual Local Area Network VLR Visitor Location Register (IN term) One of the SS components. The VLR is a database containing dynamic information about all the visiting subscribers currently in the MSC service area. Also see SS, GSM. VM Virtual Machine VPN Virtual Private Network (IN term) Example of an IN service. VPN gives e.g. companies their own private telephone network within the public system. A VPN provides the functions of a private network over the public network. The VPN service allows a user to build a private network with public network resources, i.e. over the public telephone network. A VPN enables service users to be connected from different parts of a private network over a public network, such as the PSTN. A VPN will normally work according to the numbering plan of the private network. |
| W | Top of Glossary |
WAP Wireless Application Protocol (IN term) WAP is like a bridge to mobile internet. It is the mobile telephony's answer to WWW, but WAP does not mean that you have access to the complete internet via your cellular phone. WAP only understands sites which are written in WML. The result is a simplified version of HTML, which is adapted to the small format in a cellular phone. WAP Gateway Wireless Application Protocol Gateway(IN term) An application that provides redirection of HTML documents to WAP-compatible mobile phones. WCDMA Wideband Code Division Multiple Access WfE Wait for Event WIN Wireless Intelligent Network (IN term) WML Wireless Markup Language A simplified version of HTML for WAP. WS Workstation WWW World Wide Web For further information, see World Wide Web Consortium. |
| X | Top of Glossary |
Nothing yet |
| Y | Top of Glossary |
YaST Yet another System Tool. |
| Z | Top of Glossary |
Zone TelORB term for a cluster of interconnected TelORB processors. Same as a node. |
| 0-9 | Top of Glossary |
100Base-T Fast Ethernet according to IEEE 802.3u, general definition. (Fast Ethernet communication on backplane in TelORB R14) 100Base-TX Fast Ethernet on twisted pairs. Special case of 100Base-T. (Fast Ethernet communication on cable in TelORB R14) 1000Base-T Gigabit Ethernet on twisted pairs according to IEEE 802.3ab. 3G 3rd Generation Mobile Telephony System (previously called UMTS) - NMT is 1G (analogue system). - GSM is 2G (digital system). - GPRS is kind of 2,5G since it has its origin in GSM. 3PP 3rd Party Product |
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