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4.1.3 Client Makes an Offer using ICE as described in IETFDRAFT-ICENAT-19

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Following are some SDP examples that demonstrate the offer with most of the extensions specified in this document.

The following example is an offer sent by a client.

v=0
o=- 0 0 IN IP4 172.24.32.152
s=session
c=IN IP4 172.24.32.152
b=CT:99980
t=0 0
a=x-mediabw:main-video send=585;recv=1416
a=x-devicecaps:audio:send,recv;video:send,recv
m=audio 50005 RTP/AVP 117 114 9 111 112 115 116 8 0 97 13 118 101
a=rtcp-fb:* x-message app send:dsh recv:dsh
a=rtcp-rsize
a=ice-ufrag: 6nxO 
a=ice-pwd: G6rUJNNaobz8IdDZrAbyFDoO
a=candidate:1 1 UDP 2130706431 172.24.32.152 50005 typ host 
a=candidate:1 2 UDP 2130705918 172.24.32.152 50009 typ host 
a=candidate:2 1 TCP-PASS 6556159 172.29.105.171 53127 typ relay raddr 172.29.105.171 rport 53127 
a=candidate:2 2 TCP-PASS 6556158 172.29.105.171 53127 typ relay raddr 172.29.105.171 rport 53127 
a=candidate:3 1 UDP 16648703 172.29.105.171 59353 typ relay raddr 172.29.105.171 rport 59353 
a=candidate:3 2 UDP 16648702 172.29.105.171 59627 typ relay raddr 172.29.105.171 rport 59627 
a=candidate:4 1 TCP-ACT 7076863 172.29.105.171 53127 typ relay raddr 172.29.105.171 rport 53127 
a=candidate:4 2 TCP-ACT 7076350 172.29.105.171 53127 typ relay raddr 172.29.105.171 rport 53127 
a=candidate:5 1 TCP-ACT 1684797951 172.24.32.152 50004 typ srflx raddr 172.24.32.152 rport 50004 
a=candidate:5 2 TCP-ACT 1684797438 172.24.32.152 50004 typ srflx raddr 172.24.32.152 rport 50004 
a=label:main-audio
a=cryptoscale:1 client AES_CM_128_HMAC_SHA1_80 inline:15PHFDbUI8l9/bOHUYM9geb2IakQY3tMe31TgoPC|2^31|1:1
a=crypto:2 AES_CM_128_HMAC_SHA1_80 inline:C62B/j2xrqnk18t4bxXthuGv/Lxc9DmYDG4mnAOK|2^31|1:1
a=maxptime:200
a=rtcp:50009
a=rtpmap:117 G722/8000/2
a=fmtp:117 bitrate=128000
a=rtpmap:114 x-msrta/16000
a=fmtp:114 bitrate=29000
a=rtpmap:9 G722/8000
a=rtpmap:111 SIREN/16000
a=fmtp:111 bitrate=16000
a=rtpmap:112 G7221/16000
a=fmtp:112 bitrate=24000
a=rtpmap:115 x-msrta/8000
a=fmtp:115 bitrate=11800
a=rtpmap:116 AAL2-G726-32/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:97 RED/8000
a=rtpmap:13 CN/8000
a=rtpmap:118 CN/16000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 50012 RTP/AVP 122 121 123
a=rtcp-fb:* x-message app send:src,x-pli recv:src,x-pli
a=rtcp-rsize
a=ice-ufrag: m7A0
a=ice-pwd: yfKPbeepmE8/PvGoIDFq4OId
a=x-caps:121 263:1920:1080:30.0:2000000:1;4359:1280:720:30.0:1500000:1;8455:640:480:30.0:600000:1;12551:640:360:30.0:600000:1;16647:352:288:15.0:250000:1;20743:424:240:15.0:250000:1;24839:176:144:15.0:180000:1
a=candidate:1 1 UDP 2130706431 172.24.32.152 50012 typ host 
a=candidate:1 2 UDP 2130705918 172.24.32.152 50011 typ host 
a=candidate:2 1 TCP-PASS 6556159 172.29.105.171 59400 typ relay raddr 172.29.105.171 rport 59400 
a=candidate:2 2 TCP-PASS 6556158 172.29.105.171 59400 typ relay raddr 172.29.105.171 rport 59400 
a=candidate:3 1 UDP 16648703 172.29.105.171 54004 typ relay raddr 172.29.105.171 rport 54004 
a=candidate:3 2 UDP 16648702 172.29.105.171 58581 typ relay raddr 172.29.105.171 rport 58581 
a=candidate:4 1 TCP-ACT 7076863 172.29.105.171 59400 typ relay raddr 172.29.105.171 rport 59400 
a=candidate:4 2 TCP-ACT 7076350 172.29.105.171 59400 typ relay raddr 172.29.105.171 rport 59400 
a=candidate:5 1 TCP-ACT 1684797951 172.24.32.152 50003 typ srflx raddr 172.24.32.152 rport 50003 
a=candidate:5 2 TCP-ACT 1684797438 172.24.32.152 50003 typ srflx raddr 172.24.32.152 rport 50003 
a=label:main-video
a=cryptoscale:1 client AES_CM_128_HMAC_SHA1_80 inline:KaSgBMqbVyQDtY12ihKmnNslPtpYnq1X7xko32nY|2^31|1:1
a=crypto:2 AES_CM_128_HMAC_SHA1_80 inline:1smNZ23vqTBP4oQmBHJ5NsGbSJZG/BWgS6onqlV8|2^31|1:1
a=rtcp:50011
a=x-ssrc-range:101-200
a=rtpmap:122 X-H264UC/90000
a=fmtp:122 packetization-mode=1;mst-mode=NI-TC
a=rtpmap:121 x-rtvc1/90000
a=rtpmap:123 x-ulpfecuc/90000

In the previous example, the offerer is proposing audio and video as modalities. The offerer supports both SRTP and SSRTP as the mode for encryption, and proposes that in its SDP offer using the a=crypto and a=cryptoscale attributes. The offerer only encrypts the media optionally. This is described by specifying "RTP/AVP" as the transport, even though there are a=crypto and a=cryptoscale attributes present in the SDP message.

Also note that the RTAudio, G722-Stereo, RTVideo and H.264UC codecs are represented using dynamic payloads of 114, 115, 117, 121, and 122, and are identified using their encoding names of "x-msrta", "G722", "x-rtvc1" and "X-H264UC" in their corresponding a=rtpmap attributes. The full media format name for G722-Stereo is "G722/8000/2".

The ULPFEC-UC video FEC payload format is also included in the m=video media description, using dynamic payload type 123.