[SIPForum-discussion] Bandwith modifiers in SDP.

[ashish rawat]

Hello All,

I am trying to understand the bandwidth indications  in SDP.  This video call fails because of the bandwidth issues. Can anyone help me understand why?

I also have following questions:-

1) There is "b=TIAS" and "b=AS" before m lines. Also there is "b=TIAS" lines after each m line for audio and video respectively. What does this signify?
2) If there is no "b=TIAS" line in the answer SDP, then what does this imply?


Note: Messages are truncated:


  /// CUBE received following sdp from PBX///


s=SIP Call
c=IN IP4 10.102.206.10
b=TIAS:3968000
b=AS:3968
t=0 0
m=audio 16636 RTP/AVP 108 109 110 9 104 105 8 0 18 101
b=TIAS:64000

m=video 16638 RTP/AVP 97 126
b=TIAS:3904000


  /// CUBE forwards following SDP to the Provider///

s=SIP Call
c=IN IP4 10.102.206.10
b=TIAS:3968000
b=AS:3968
t=0 0
m=audio 16636 RTP/AVP 108 109 110 9 104 105 8 0 18 101
b=TIAS:64000

m=video 16638 RTP/AVP 97 126
a=label:11
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=428016;packetization-mode=0;max-mbps=245000;max-fs=9000;max-cpb=200;max-br=5000
a=rtpmap:126 H264/90000
a=fmtp:126 profile-level-id=428016;packetization-mode=1;max-mbps=245000;max-fs=9000;max-cpb=200;max-br=5000
m=application 16642 RTP/AVP 100
a=rtpmap:100 H224/0



   ///  Provider responds with the following SDP in 200 ok///

c=IN IP4 10.102.206.37
b=AS:64
t=0 0
m=audio 49188 RTP/AVP 9 8 0 18 113 15 101

m=video 49190 RTP/AVP 97 126 111 96 34

b=TIAS:64000
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=428020; max-mbps=244800; max-fs=8160; sar=13
a=rtpmap:126 H264/90000
a=fmtp:126 profile-level-id=428020; packetization-mode=1; max-mbps=244800; max-fs=8160; sar=13
a=rtpmap:111 H264/90000
a=fmtp:111 profile-level-id=640020; packetization-mode=1; max-mbps=244800; max-fs=8160; sar=13
a=rtpmap:96 H263-1998/90000
a=fmtp:96 CIF4=2;CIF=1;QCIF=1;SQCIF=1;F;J;T
a=rtpmap:34 H263/90000
a=fmtp:34 CIF4=2;CIF=1;QCIF=1;SQCIF=1;F
a=sendrecv
m=application 49192 RTP/AVP 100
a=rtpmap:100 H224/4800
a=sendrecv


    //// CUBE responds to the PBX with 200 Ok with the following sdp answer///

c=IN IP4 10.102.206.37
b=AS:64
t=0 0
m=audio 49188 RTP/AVP 9 8 0 18 113 15 101
m=video 49190 RTP/AVP 97 126 111 96 34
b=TIAS:64000
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=428020; max-mbps=244800; max-fs=8160; sar=13
a=rtpmap:126 H264/90000
a=fmtp:126 profile-level-id=428020; packetization-mode=1; max-mbps=244800; max-fs=8160; sar=13
a=rtpmap:111 H264/90000
a=fmtp:111 profile-level-id=640020; packetization-mode=1; max-mbps=244800; max-fs=8160; sar=13
a=rtpmap:96 H263-1998/90000
a=fmtp:96 CIF4=2;CIF=1;QCIF=1;SQCIF=1;F;J;T
a=rtpmap:34 H263/90000
a=fmtp:34 CIF4=2;CIF=1;QCIF=1;SQCIF=1;F
a=sendrecv
m=application 49192 RTP/AVP 100
a=rtpmap:100 H224/4800
a=sendrecv

Thanks,
Ashish Rawat
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