[SIPForum-discussion] Can we specify (m = audio 0 ..) audio port as zero for hold scenario.

[Arunachala]

Hi,
   AFAIK, hold can be initiated by just having the IP in c-line of SDP to
0.0.0.0. RFC3264 does NOT recommend this way of putting a stream on hold.
But, many SIP entities do follow it (as recommended by the obsolete
RFC2543). So, we DO NOT need the port to be set to zero to initiate a hold
event.

   According to RFC3264, an existing media stream can be removed by setting
the port of that stream to zero. So, here who ever is sending re-INVITE with
port value 0 in the m-line is saying,  that media is no longer sent for that
stream, and any media that is received is discarded.

Regards,
Arunachal




On Thu, Jan 8, 2009 at 11:56 PM, <ashok.pitambar at wipro.com> wrote:

>  Hi All,
>
> By setting the audio port to zero in reinvite , will it invoke hold?
>
> call folw:
>
> A                       B
>   ----INV------->
>  m=audio 29590..
>  < ------200------------
> m=audio 4100..
> --------ACK----------->
>    call established
>
> ---------INV-(hold)---->
> c=IN IP4 0.0.0.0
> m=audio 29590..
> a=sendonly
> <----------200------------
>  m=audio 4100..
> ----------ACK---------->
>
> ---------INV--(hold)----->
>  c=IN IP4 0.0.0.0
> m=audio 0...
> a=inactive
>
>
>
> Regards ,
> ASHOK PITAMBAR
>
>
>
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