3 Definitions, symbols and abbreviations

23.2843GPPLocal Call Local Switch (LCLS)Release 17Stage 2TS

3.1 Definitions

For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].

BSS ID: A globally unique identifier of a Base Station Subsystem (BSS).

call leg: The access link between the mobile station and the Core Network. A mobile to mobile call consists of two call legs and the link through the Core Network.

call leg correlation: The process within the BSS to search for the other call-leg(s) of a (potential) Intra-BSS call by appropriate means.

intra-BSS call: A mobile to mobile voice call involving two mobile stations connected to the same BSS.

intra-BSS call detection: Determination that both call legs are within the same BSS.

local call: An Intra-BSS call that can be locally switched by the BSS.

locally switched call: A local call with a direct local path between the Call-legs, switched by the BSS.

3.2 Symbols

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

A Interface between the BSC and the MSC-S

Abis Interface between the BSC and the BTS

i intermediate node prefix.

Mc Interface between the (G)MSC-S and the MGW.

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

o originating side prefix, e.g. oUE, oBSS, oMSC, oMGW for nodes and e.g. oA-interface, oAssignment Request etc for interfaces, messages etc.

t terminating side prefix , e.g. tUE, tBSS, tMSC, tMGW and e.g. tA-interface, tAssignment Request etc for interfaces, messages etc.

3.3 Abbreviations

For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1].

AoIP A over IP, using IP as the bearer of the user plane of A interface

AoTDM A over TDM, using TDM as the bearer of the user plane of A interface

APM Application Transport Mechanism

COT Continuity message

GCR Global Call Reference

LCLS Local Call Local Switch

OoBTC Out of Band Transcoder Control