3.1.5.3 Instant Messaging
The SDP signaling for an instant messaging session using the previous RTC 1.2 APIs is shown in the following.
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v=0 o=- 0 0 IN IP4 172.27.174.212 s=session c=IN IP4 172.27.174.212 t=0 0 m=x-ms-message 5060 sip null
Note The target of the instant messaging session in this case is carried in the To header of the INVITE request.
The SDP signaling for an instant messaging session using the RTC 1.3 APIs is shown in the following.
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v=0 o=- 0 0 IN IP4 157.56.66.71 s=session c=IN IP4 157.56.66.71 t=0 0 m=message 5060 sip sip:peer@tradewind.com
The SIP URI present in the SDP signaling is the SIP URI of the peer user with whom a user wants to establish an IM session. This matches the SIP URI in the To header of the INVITE request. The port indicates the listening port of the client for direct connections if that is supported. The port SHOULD be ignored if the clients are connected through a server. The 1.3 client can also accept the older 1.2 format (which has null for the SIP URI and uses x-ms-message as the media type).