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.