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

Thu Jan 15 09:42:30 UTC 2009

Hi Ashok,

Audio port zero treatment depends on what was the "a" attribute in
earlier INV for which re-INV is being send, according to rfc. However,
setting port to zero is not sufficient to put call on hold in most of
the cases. It is because end-point might need RTCP packet and RTCP
packet comes relative port of RTP port. So RRTCP packet might not be
delivered to end-point if audio port is set to zero and if end-point is
expecting RTCP packet. Setting audio port to zero will work for hold
but adding appropriate "a" attribute value  in re-INV depending on earlier "a"
attribute in that INV will be more robust. Moreover, setting it to zero in re-INVITE indicates non-acceptance of RTP. If re-INV transaction has succeded, that port treatment(port meaning) should be accepted else no affect to SDP on earlier INV.

Thanks and regards
~Nabam

________________________________
From: "ashok.pitambar at wipro.com" <ashok.pitambar at wipro.com>
To: nabamserbang at yahoo.com
Sent: Thursday, January 15, 2009 10:00:09 AM
Subject: RE: [SIPForum-discussion] Can we specify (m = audio 0 ..) audio port aszero for hold scenario.

Hi
nabam,

Thanks for you input
,

The RFC 3264 (offer/answer)( http://www.ietf.org/rfc/rfc3264.txt 
) sections

1 .8.2 Removing a Media Stream
2. 8.4 Putting a Unicast Media Stream on
Hold

RFC also specifies about use of port 0 in as
"Of course, when used, the port
   number MUST NOT be zero,
which would specify that the stream has been
   disabled"
please check 8.4 Putting a Unicast Media Stream on Hold
section.

Regards ,
ASHOK PITAMBAR
Wipro-Nortel Multi-Media
Applications
Electronics City I, Tower 2,
1th Floor, B Wing, Bangalore- 560 100
Mob: +91-9008122004 |  Ph: +91-80-4122 1111 Ext.:2162 |  ESN:8696 
Email: ashok.pitambar at wipro.com| Website: www.wipro.com

________________________________
 From: nabam serbang
[mailto:nabamserbang at yahoo.com] 
Sent: Monday, January 12, 2009 4:05
PM
To: Ashok Pitambar (WT01 - Telecom Equipment); Srinivas Banda (WT01
- Telecom Equipment)
Cc: discussion at sipforum.org
Subject: Re: [SIPForum-discussion] Can we specify (m = audio 0 ..) audio port aszero for
hold scenario.

Hi Ashok,

I you might like to digg at RFC 3264 at http://www.ietf.org/rfc/rfc3264.txt?number=3264
Rfc  basically is for
med-dialog update of SDP but applies to other cases as well.

Nabam
Serbang
Software Engineer, Avaya,
Home Page: http://sites.google.com/site/nabamserbang/

________________________________
 From: "ashok.pitambar at wipro.com"
<ashok.pitambar at wipro.com>
To: srinivas.banda at wipro.com
Cc: discussion at sipforum.org
Sent: Sunday, January 11, 2009 11:33:38
AM
Subject: Re:
[SIPForum-discussion] Can we specify (m = audio 0 ..) audio port aszero for hold
scenario.

Hi Srinivas,

    Thanks for your input,
do you have any idea which of SIP or SDP related RFC's specify this kind of
hold? Is this is responsibility of sip stack to take care this kind of hold
scenario.Because in our case MG(Media Gateway) is replying with 510 protocol
error for MGCP message(MDCX) with m = audio 0 ..& hence sip with 4XX
response.

Thanks,
Regards,
Ashok Pitambar

________________________________
 From: Srinivas Banda (WT01 - Telecom
Equipment)
Sent: Fri 1/9/2009 11:33 PM
To: Ashok Pitambar
(WT01 - Telecom Equipment)
Subject: RE: [SIPForum-discussion] Can we
specify (m = audio 0 ..) audio port aszero for hold
scenario.

Apart from port 0, you should change the media attribute to
"inactive/sendonly". sendonly will be used if you have music on hold
option.

Regards
Srinivas

________________________________
 From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of ashok.pitambar at wipro.com
Sent: Friday, January 09, 2009 2:57
AM
To: discussion at sipforum.org
Subject: [SIPForum-discussion] Can we specify (m = audio 0 ..) audio port aszero for hold
scenario.

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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