3 Symbols and abbreviations

23.2053GPPBearer-independent circuit-switched core networkRelease 17Stage 2TS

3.1 Symbols

For the purposes of the present document, the following symbols apply:

Iu Interface between the RNS and the core network. It is also considered as a reference point.

Mc Interface between the server and the media gateway.

Nb Interface between media gateways.

Nc The NNI call control interface between (G)MSC servers.

3.2 Abbreviations

For the purposes of the present document, the following abbreviations apply:

BCF Bearer Control Function

BICC Bearer Independent Call Control

CIC Call Instance Code

CCF Call Control Function

CS Circuit Switched

GERAN GSM/EDGE Radio Access Network

IAM Initial Address Message

IETF Internet Engineering Task Force

IP Internet Protocol

IPv4 Internet Protocol version 4

IPv6 Internet Protocol version 6

LCLS Local Call Local Switch

MGW Media GateWay

MGC Media Gateway Controller

MSC-S MSC Server

MTP2 Message Transfer Part layer 2

MTP3 Message Transfer Part layer 3

NNI Network-Network interface

RAB Radio Access Bearer

RANAP Radio Access Network Application Protocol

SBSS Serving Base Station System

SRNS Serving Radio Network Subsystem

TCAP Transaction Capabilities Application Part

TFO Tandem Free Operation

TRAU Transcoder and Rate Adapter Unit

TrFO Transcoder Free Operation

UDP User Datagram Protocol

UTRAN UMTS Terrestrial Radio Access Network

3.3 Definitions

UE : User equipment. This specification makes no distinction between MS (mobile station) and UE.

A/Gb mode: mode of operation of the UE when connected to the Core Network via GERAN and the A and/or Gb interfaces. Throughout this specification the term GSM refers to GERAN A/Gb mode.

Iu mode: mode of operation of the UE when connected to the Core Network via GERAN or UTRAN and the Iu interface. Throughout this specification the term UMTS refers to UTRAN or GERAN Iu mode.