SDP表示Session Description Protocol，Webrtc是通过SDP进行协商，进而创建出符合通话要求的Session。SDP在webrtc应用中扮演着重要的角色，接下来我们通过一个实例来简单介绍一下SDP信息的含义。
本例是安卓手机和电脑网页建立的视频通讯会话，具体的SDP信息如下所示：
移动端（安卓）：
"sdp" -> "v=0
o=- 7644049451648220451 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE audio video
a=msid-semantic: WMS ARDAMS
m=audio 44585 UDP/TLS/RTP/SAVPF 111 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 172.31.200.23
a=rtcp:9 IN IP4 0.0.0.0
a=candidate:2586587190 1 udp 2122260223 172.31.200.23 44585 typ host generation 0 network-id 3 network-cost 10
a=candidate:559267639 1 udp 2122202367 ::1 45075 typ host generation 0 network-id 2
a=candidate:1510613869 1 udp 2122129151 127.0.0.1 34137 typ host generation 0 network-id 1
a=ice-ufrag:Rcuq
a=ice-pwd:OxDSE1pHNWhgcdHaX/3cYLE1
a=ice-options:trickle renomination
a=fingerprint:sha-256 49:B6:A0:48:F8:EB:82:1D:FB:DE:B9:22:33:0E:91:EE:60:34:73:45:2B:C3:92:3A