4 Xn signalling bearer

38.4223GPPNG-RANRelease 16TSXn signalling transport

4.1 Functions and protocol stack

Xn-C signalling bearer provides the following functions:

– Provision of reliable transfer of XnAP message over Xn-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 Xn-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: Xn-C signalling bearer protocol stack

The Transport Network Layer is based on IP transport, comprising SCTP on top of IP.