3 Definitions of terms, symbols and abbreviations
37.4723GPPRelease 17Signalling transportTSW1 interface
3.1 Terms
For the purposes of the present document, the terms and definitions given in 3GPP 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 3GPP TR 21.905 [1].
ng-eNB: as defined in 3GPP TS 38.300 [6]
SCTP association: as defined in IETF RFC 4960 (2007-09) [5]
SCTP endpoint: as defined in IETF RFC 4960 (2007-09) [5]
W1: interface between a ng-eNB-CU and a ng-eNB-DU, providing an interconnection point between the ng-eNB-CU and the ng-eNB-DU.
W1-C: Reference point for the control plane protocol between ng-eNB-CU and ng-eNB-DU.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP 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 3GPP TR 21.905 [1].
DiffServ Differentiated Service
IANA Internet Assigned Number Authority
IP Internet Protocol
PPP Point to Point Protocol
SCTP Stream Control Transmission Protocol
4. W1-C signalling bearer
4.1 Function and protocol stack
The W1-C signalling bearer provides the following functions:
– Provision of reliable transfer of W1AP messages over the W1-C interface.
– Provision of networking and routeing function.
– Provision of redundancy in the signalling network.
– Support for flow control and congestion control.
The protocol stack for W1-C Signalling Bearer is shown in figure 4.1-1 and details on each protocol are described in the following clauses.
Figure 4.1-1: W1-C signalling bearer protocol stack
The Transport Network Layer is based on IP transport, comprising SCTP on top of IP.