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Beginner

Empty video port in SDP request

Hello,

I'm currently working on a cisco devnet sandbox environment, which has a CUCM 9.1 and a Jabber guest server.

My goal is to connect a softphone i developped to this environment and receive video calls from jabber web pages.

The jabber page and the softphone are both running on my computer.

The SIP call flow is all done and works fine, but i get a void video port from the ACK request of the CUCM once the INVITE has been accepter.

This is the SDP packet which is in the OK response i send to CUCM after the INVITE from the jabber guest (replaced ips with {comments}) :

v=0

o=1120 181025627 181025627 IN IP4  {sofpthone computer ip}

s=operator1

p=1120

c=IN IP4  {sofpthone computer ip}

t=0 0

m=audio 35500 RTP/AVP 0

a=rtpmap:0 PCMU/8000

m=video 35505 RTP/AVP 96

a=rtpmap:96 H264/90000

And this is the SDP packet from the ACK request (replaced ips with {comments}):

v=0

o=CiscoSystemsCCM-SIP 85475 1 IN IP4 {CUCM ip}

s=SIP Call

c=IN IP4 {jabber guest ip}

b=TIAS:64000

b=AS:64

t=0 0

m=audio 17134 RTP/AVP 0

b=TIAS:64000

a=rtpmap:0 PCMU/8000

a=ptime:20

m=video 0 RTP/AVP 31 34 96 97

a=rtpmap:31 H261/90000

a=rtpmap:34 H263/90000

a=rtpmap:96 H263-1998/90000

a=rtpmap:97 H264/90000

a=content:main

a=inactive

As you can see, the video port has a value of zero, which obviously cannot be used to stream. What could be the cause of this ?

3 REPLIES 3
Highlighted
Cisco Employee

Re: Empty video port in SDP request

Could be a call to a device without video or some sort of announcement.

Highlighted
Beginner

Re: Empty video port in SDP request

Well, the device running the jabber guest page is the same computer that runs the softphone, so it does have a video peripheral (a webcam).

That said, it is used by both the softphone and the jabber guest page, could that be the problem ?

Highlighted
Cisco Employee

Re: Empty video port in SDP request

That could definitely be the problem. The camera is probably only attached to one of the running applications.

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