Glossary

ACK

Acknowledgment

ACM

Address Complete Message

AIN

Advanced Intelligent Network

"The Advanced Intelligent Network (AIN) is a telephone network architecture that separates service logic from switching equipment, allowing new services to be added without having to redesign switches to support new services. Developed by Bell Communications Research, AIN is recognized as an industry standard in North America."

AIOD

Automatic Identified Outward Calling

ANI

Automatic Number Identification

ANM

Answer Message

ANSI

American National Standards Institute

ANSI facilitates the development of US domestic standards through consensus processes and communicates US standards to the international standards arena.

ANSI-41

ANSI-41

Is the standard for transaction based functionality on non-GSM cellular networks. Provides provision of SMS / HLR Update type services.

API

Application Programming Interface

"Access to the functionality of a software package is provided to a programmer/user through an API. The API could be a library that presents a set of function calls that a programmer can access at compile or run time or a GUI based API , message based API etc.."

ASCII

American Standard Code for Information Interexchange (ANSI)

"The ANSI 7-bit character code with, with an 8th bit for parity checking."

ASN.1

Abstract Syntax Notation 1

"ASN.1 is an internationally standardised, vendor independent, platform independent, and language independent notation for specifying data structures at a high level of abstraction. Used extensively to encode data structures in SS7 for transaction based signalling - i.e. TCAP, MAP, INAP"

AUC

Authentication Centre

The AUC stores confidential data and keys in a GSM network that are used to provide security.

BCD

Binary Coded Decimal

BCD uses four bits to represent digits

BCI

Backward Call Indicators

BCLID

Bulk Calling Line Identification

BER

Basic Encoding Rules

BRA

Basic Rate Access ISDN

The provision of an ISDN service through 1.44kbits/s access

BSN

Backward Sequence Number

CAS

Channel Associated Signalling

Term given to protocols where dedicated channels are assigned to each traffic channel.

CCITT

Consultative Committee on International Telephone & Telegraph

This was the previous (before June 1994) for ITU-T

CCS

Common Channel Signaling

A mode of operation whereby the the signalling channel is used as a datalink to carry call control and management signals and is not dedicated to particular bearer channels in a fixed pattern.

CDMA

Code Division Multiple Access

"Under CDMA, communications channels are created by assigning a special coding scheme to information flows. CDMA-based second generation cellular radio systems are in use in parts of Asia and North and South America."

CDSL

Customer Digital Subscriber Line

CGB

Circuit Group Blocking Message

CGU

Circuit Group Unblocking Message

CIC

Carrier Identification Code

The CIC is a number used by switches at each end of a point-to-point telephony circuit (controlled by ISUP or TUP) to identify a specific bearer channel. The bearer channel is typically a single time slot on a T-1/E-1 interface

CIDS

Calling Identity Delivery & Suppression

CLID

Calling Line ID

CLLI

Common Language Location Identification

CNAM

Calling NAMe

CNAM is an Intelligent Network service which allows delivery to the subscriber of the calling party number and a readable calling name in digital readout, identifying the caller to the called party.

COT

Continuity Test Message

CPG

Call Progress Message

CRA

Circuit Reservation Acknowledgment Message

CRC-4

Cyclic Redundancy Check

A method of checking for transmission errors in E1 trunk lines.

CRM

Circuit Reservation Message

CS-1

Capability Set 1

Refers to the SS7 Intelligent Network (IN) Standard ITU-T Intelligent Network CS-1 Standard

CSC

Circuit Supervision Control

CVR

Circuit Validation Response Message

CVT

Circuit Validation Test Message

DPC

Destination Point Code

The DPC is the Point Code Number for the piece of SS7 network equipment receiving SS7 Signalling

DPNSS

Digital Private Network Signalling System

A common channel signalling protocol for linking private digital exchanges (enabling PBX facilities such as call forwarding to work over the entire network)

DSL

Digital Subscriber Line

There are many forms of DSL - this is the transmission technology carrying signalling over the local loop.

DSS1

Digital Subscriber Signalling System no 1

This is an ISDN user network interface. It is a common channel digital access signalling system. ITU-T recommendation is Q.931 and ETSI EN 300 403-1

DTMF

Dial Tone Multifrequency

A tone signalling system available to POTS users with a multi-frequency key pad

E1

E1

"The European standard (see North American T1). E1 carries information at the rate of 2.048 millions bits per second. E1 30 channels, 2.048 Mbps."

EIR

Equipment Identification Register

The EIR in a GSM Network stores the serial numbers (supplied by manufacturers) of the mobile terminals IMEI.

ETSI

European Telecommunications Standards Institute

ETSI produce regional telecom signalling protocol standards that are subsequently used in Europe and elsewhere.

FISU

Fill-in Signal Unit

FSK

Frequency Key Shifting

FSN

Forward Sequence Number

FSS

Facility Selective Service

FTP

Fast Transfer Protocol (IETF)

GPRS

General Packet Radio Services

Packet switched data radio technology for GSM Networks. GPRS connections are always open giving mobile terminal users the same kind of network availability they may be used to from corporate networks. There are no set up and clear down times associated with data calls made via GPRS. Terminals can therefore effectively become a part of the Internet.

GRS

Group Reset Message

GSC

Gateway Switching Center

GSM

Global System for Mobile communication

TDMA based second generation mobile Cellular Radio technology, originated in Europe but now used in over 100 countries around the world. GSM supports voice, data and text messaging and allows roaming between different networks, which means that GSM users can take their phones with them to many parts of the world.

GTT

Global Title Translations

GTV

Global Title Value

H.323

H.323

An ITU-T suite of protocols designed for controlling multimedia communications over IP

HDLC

High Level Data Link Control

HLR

Home Location Register

An HLR is a central database in a GSM network that stores all permanent subscriber data and the relevant temporary data of all subscribers.

IAM

Initial Address Message

ICP

Intelligent Call Processing

ICR

Intelligent Call Router

IDLC

Integrated Digital Loop Carrier

IDT

Integrated Digital Terminal

IEEE

Institute of Electrical and Electronics Engineers

IETF

Internet Engineering Task Force

IMEI

International Mobile Station Equipment Identity

The IMEI uniquely identifies GSM mobile terminals internationally - it's a serial number. Allocated by the manufacturer and registered in the network by operators in the EIR.

IMSI

International Mobile Subscriber Identity

When registering for a service on a GSM network a subscriber is assigned an IMSI number. Calls and services can only be used by a subscriber with a SIM card with a valid IMSI and IMEI number

INAP

Intelligent Network Application Part

SS7 Protocol enabling Intelligent Network services. Networks using INAP deliver easily programmable services on a per customer basis, such as follow-me, televoting, pre-paid, and credit card calls.

INR

Information Request Message

IP

Intelligent Peripheral or Internet Protocol (IETF)

IPC

Interprocess Communication

IPI

Intelligent Peripheral Interface

ISDN

Integrated Services Digital Network

ISDN - Integrated Services Digital Network (ISDN) is a CCITT standard, covering a range of voice, data, and image services. It provides end to end, simultaneous handling of digitised voice and data traffic on the same links, via the same exchanges.

ISDNUP

ISDN User Part

ISO

International Standards Organization

ISPC

International Signaling Point Code

ISUP

ISDN User Part (circuit related)

The functional part of the Signaling System No. 7 (SS7) protocol, (i.e., the part that specifies the interexchange signaling procedures for the setup and tear down of trunk calls between networks).

ITU

International Telecommunication Union

ITU-T

Telecommunication Standardization Sector (of ITU)

Before June 1994 the ITU-T was known as CCITT

ITU-TS

Telecommunication Standardization Sector (of ITU)

IVR

Interactive Voice Response

Interactive Voice Response refers to those systems that provide information in the form of recorded messages over telephone lines in response to user input

LAN

Local Area Network

A communication system that provides reliable high-speed, point to point, connections for routing data packets between devices in a single building or complex.

LCN

Logical Channel Number (x.25)

LI

Length Indicator

LINK SETS

Link Sets

Signaling data links are grouped into link sets. All links in a link set must connect to a single point code. Up to 16 links can be assigned to a single link set.

LNP

Local Number portability

LOCREQ

Location Request

LSSU

Link Status Signaling Unit

MAP

Mobility Application Part

The SS7 Protocol layer MAP provides a GSM Network with a mechanism to communicate between its component parts and other networks. It allows MSCs to communicate with VLR,HLR's and BSC's.It provides the underlying signalling for SMS and Location Based services.

MIN

Mobile Identification Number

MSC

Mobile Switching Center

The switching node of a GSM network is the Mobile Switching Centre. The MSC performs all the switching functions of a fixed-network switching node, e.g. routing path search,signal routing and service feature processing. In addition it has to control allocation of radio resources and subscriber mobility.

MSISDN

Mobile Station ISDN Number

The real telephone number of a GSM subscriber. A mobile subscriber can have many MSISDN numbers - for different services - voice,fax,data

MSRN

Mobile Station Roaming Number

A temporary location-dependent ISDN number on GSM Networks. It is assigned to the locally responsible VLR to each mobile station in its area.

MSU

Message Signaling Unit

MTP

Message Transfer Part

Provides physical, data link, and network layer functions. MTP transports information from the upper layers (including the user parts and SS7 applications) across the SS7 network and includes the network management procedures to reconfigure message routing in response to network failures. Refers to level 1 through 3 in the SS7 protocol stack (MTP1-MTP3).

MUX

Multiplexer

A device used to allow a single communication circuit to take the place of several parallel ones. At the other end of the link a demultiplexer separates the channels.

NCP

Network Control Point

NIC

Network Interface Card

An interface card allowing a node to be connected to a LAN.

OPC

Origination Point Code

The OPC is the Point Code of the SS7 equipment that is transmitting the SS7 signalling.

PBX

Private Branch Exchange

A switching system owned by a client that acts as an in-house telephone exchange with advanced features and capabilities.

PCM

Pulse Code Modulation

A method of digitally encoding speech

Point Code

Point Code

A number that uniquely identifies a node in an SS7 network. Used to direct messages to the appropriate destination. Each switch, Service Control Point (SCP), Signal Transfer Point (STP), and IP (Intelligent Peripheral) has a unique point code in the SS7 network.

POTS

Plain Old Telephony System

PPP

Point-to-Point Protocol

PRI

Primary Rate Interface

PSTN

Public Switched Telephone Network

Q.931

Q.931

A well know ITU-T standard for access signalling between an ISDN terminal and narrow band ISDN network.

R2

Region or Register Signalling

R2 or CAS signalling is still in common use today (most widely MFC R2), but has been superceded by other forms of signalling such as ISDN and SS7.

RTP

Real-time Transport Protocol

Proxy server for RTP streams, that is supported on SS7 Media Gateway and Class 4 Softswitch

SCCP

Signaling Connection Control Part

This allows non-circuit related signalling (such as TCAP) to be carried over SS7 routes.

SCE

Service Creation Environment

This allows the creation of services in an SS7 Intelligent Network environment.

SCP

Service Control Point (SS7)

Service Control Points contain centralized network databases for providing enhanced services. The SCP accepts queries from the Service Switching Point (SSP) and returns the requested information to the requestor.

SDLC

Synchronous Data Link Control

SDSL

Symmetric Digital Subscriber Line

SEP

Signaling Endpoint

SF

Status Field

SI

Service Indicator

SIB

Service Independent Building Blocks

In the area of SS7 based Intelligent Networks this refers to the abstract representation of IN capabilities that allow IN services to be built.

SIF

Signaling Information Field

SIM

Subscriber Identity Module

In GSM networks a subscriber is associated with a mobile station via the means of a personal chip card.

SIO

Signaling Information Octet

SIO contains information on the identity of the user of an SS7 MTP message - eg. ISUP, TCAP

SIP

Session Initiation Protocol

SIP is an IETF initiative that provides an alternative to the H.323 standard for VoIP signalling.

SLC

Signaling Link Code

SMPP

Short Message Peer to Peer

This protocol allows communication into and between SMSC's. Often this protocol is provided as a means of providing third party SMS applications with single or bulk SMS delivery.

SMS

Short Message Service

A text message service that enables short messages of generally no more than 140-160 characters in length to be sent and transmitted from a cell phone. In a GSM network this service is enabled by the SS7 MAP Protocol.

SMSC

Short Message Service Centre

A node in the network that receives all mobile originated text messages, determines the current status of the recipient, forwards the message to the appropriate destination subscriber, or stores them for later transmission.

SMTP

Simple Mail Transfer Protocol

SNMP

Simple Network Management Protocol (IETF)

SS7

Signaling System #7

SS7 is a global standard for telecommunications defined by the International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T). It provides protocol signalling standards for both fixed and cellular networks allowing for circuit based telephony calls and transaction based services - i.e. delivery of SMS , Intelligent Network Services.

SSP

Service Switching Point

Service Switching Points are telephone switches interconnected by SS7 links. SSPs perform call processing on calls that originate, tandem, or terminate at that site. SSPs generate SS7 messages to transfer call-related information to other SSPs or to query an SCP for routing instructions.

STP

Signaling Transfer Point

Signal Transfer Points are switches that relay messages between network switches and databases. Their main function is to route SS7 messages to the correct outgoing signaling link, based on SS7 message address fields.

T1

T1

A North American standard - 1.544 Mbps point-to-point dedicated, digital circuit provided by the telephone companies. T1 (DS1): 24 channels, 1.544 Mbps.See E1 for European standard.

TCAP

Transaction Capabilities Application Part

Used for transporting non-circuit, transaction-oriented data across an SS7 network. Initially used for 800 number translation now used to implements services for applications such as GSM-MAP and IS-41. These applications provide IN services such as Home Location Register (HLR) or Short Message Service (SMS).

TCP

Transmission Control Protocol

TCP/IP

Transmission Control Protocol/Internet Protocol

TDMA

Time Division Multiple Access

A method of allowing lower-speed channels to share a high-speed communication circuit, by allocating separate time slots to each channel. Each channel has access to the entire bandwidth of the link for a restricted time.

TMSI

Temporary Mobile Subscriber Identity

In a GSM network the VLR can assign a TMSI in place of an IMSI for definite identification purposes in the area handled by the VLR.

TUP

Telephone Users Part

UDP

User Datagram Protocol

UMTS

Universal Mobile Telecommunications Service

UMTS provides the European standard for 3G specified by ETSI. Whereas GSM uses TDMA , where each device has a fixed time slot allocation for the duration of a call, UMTS uses W-CDMA.

USSD

Unstructured Supplementary Services Data

USSD is a means of transmitting data or instructions over GSM Networks. It operates by providing a connection across the GSM network over which data is sent. Text messages can be up to 182 characters in length.

VLR

Visitor Location Register

In a GSM network the VLR stores the data for all mobile stations that are currently staying in the administrative area of the associated MSC - typically there is a VLR per MSC.

VOIP

Voice Over Internet Protocol

Describes the provision of voice services over the packet based Internet Protocol - IP.

VPN

Virtual Private Network

WAN

Wide Area Network

WATS

Wide Area Telephone Service