[Type text]

Figure 23. WebRTC – IMS/RCS Signaling
For RCS signaling-only features, the implementation options are:
1. RCS XDMS features including contact list support, has a defined XCAP interface.
• WebRTC IMS client can use XCAP signaling to the XDMS server.
2. RCS presence can be supported by the WebRTC app in one of two ways:
• Use SIP-over-Web socket. Signaling is handled through the WebRTC GW.
• Use OMA presence RESTful API.
3. RCS IM in pager mode uses a single IM carried in signaling only. There are two implementation
options:
• Use SIP-over-Web socket. Signaling is handled through the WebRTC gateway.
• Use OMA Chat RESTful API.
Figure 24 illustrates an IMS-RCS architecture for signaling and media bearer.
The Evolution of 3GPP Communications Services – 5G Americas – July 2016
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