Re: [Sip] Getting "Media Format = 0"

[Nitin Kapoor <[e-mail]>]

Hello,

Can anyone please help me out on the below issue.

Thanks,
Nitin Kapoor

On 12 March 2010 09:06, Nitin Kapoor <[e-mail]> wrote:

> Hello Friends,
>
> I am facing the problem with one of my client. I can see we are getting the
> 2 codecs in SDP(G.711 & G.729) with payload "0, 101, 19".
>
> Now here is my doubt is that whenver my client is sending the SDP in
> initial OFFER with G.729 its offering "Media format = 0".But when i checked
> the RFC 3264 and others, then i observed that it can be possible if you have
> two codecs in one SDP then one media format can be "0".
>
> Below is the OFFERED SDP from my SOURCE UA.
>
> Media Description, name and address (m): audio 17890 RTP/AVP 0 101 19
> Media Type: audio
> Media Port: 17890
> Media Protocol: RTP/AVP
> Media Format: ITU-T G.711 PCMU
> Media Format: DynamicRTP-Type-101
> Media Format: Comfort noise (old)
>
> Connection Information (c): IN IP4 212.48.160.163
> Connection Network Type: IN
> Connection Address Type: IP4
> Connection Address: 212.48.160.163
>
> Media Attribute (a): rtpmap:0 PCMU/8000
> Media Attribute Fieldname: rtpmap
> Media Format: 0
> MIME Type: PCMU
> Sample Rate: 8000
>
> Media Attribute (a): rtpmap:101 telephone-event/8000
> Media Attribute Fieldname: rtpmap
> Media Format: 101
> MIME Type: telephone-event
> Sample Rate: 8000
>
> Media Attribute (a): fmtp:101 0-16
> Media Attribute Fieldname: fmtp
> Media Format: 101 [telephone-event]
> Media format specific parameters: 0-16
> Media Attribute (a): rtpmap:19 CN/8000
> Media Attribute Fieldname: rtpmap
> Media Format: 19
> MIME Type: CN
> Sample Rate: 8000
>
> Media Attribute (a): ptime:20
> Media Attribute Fieldname: ptime
> Media Attribute Value: 20
>
> Here is SDP is offered by my Remote Entity in 183 Session progress in the
> correspondence of of INITIAL INVITE.
>
> Media Description, name and address (m): audio 5870 RTP/AVP 0 101
> Media Type: audio
> Media Port: 5870
> Media Protocol: RTP/AVP
> Media Format: ITU-T G.711 PCMU
> Media Format: DynamicRTP-Type-101
> Media Attribute (a): rtpmap:0 PCMU/8000
> Media Attribute Fieldname: rtpmap
> Media Format: 0
> MIME Type: PCMU
> Sample Rate: 8000
> Media Attribute (a): sendrecv
> Media Attribute (a): rtpmap:101 telephone-event/8000
> Media Attribute Fieldname: rtpmap
> Media Format: 101
> MIME Type: telephone-event
> Sample Rate: 8000
>
>
> Now the problem which i am facing is that after  doing the Negotiation and
> the ACK of 200 OK in the correspondence in INITIAL OFFER/INVITE, i am
> getting a BYE  immediately from my source UA.
>
> Could anyone please help me to diagnose this.
>
> Thanks,
> Nitin kapoor
>
>