Contact header in 200 OK

[sandip gangakhedkar]

Hi all,

I'd like to know if the Contact header is mandatory for a 200 OK response to
an INVITE request.

The RFC doesnt explicitly mention anything in this regard although a 200 OK
is mandatory for a REGISTER request.

If the originating endpoint receives the Contact header in the 180 Ringing
response (which I assume is mandatory), then it knows the location of the
remote endpoint, in which case the Contact header would be redundant in the
200 OK response.

Waiting for some expert intervention.. :)

Regards,

[T Satyanarayana-A12694]

The RFC does mention this. In table 2, on page 162.

Header field where proxy ACK BYE CAN INV OPT REG
___________________________________________________________
Contact 2xx - - - m o o

regards
Satya T


________________________________

From: sip-***@ietf.org [mailto:sip-***@ietf.org] On Behalf Of
sandip gangakhedkar
Sent: Thursday, August 06, 2009 8:16 PM
To: ***@ietf.org
Subject: [Sip] Contact header in 200 OK


Hi all,

I'd like to know if the Contact header is mandatory for a 200 OK
response to an INVITE request.

The RFC doesnt explicitly mention anything in this regard although a 200
OK is mandatory for a REGISTER request.

If the originating endpoint receives the Contact header in the 180
Ringing response (which I assume is mandatory), then it knows the
location of the remote endpoint, in which case the Contact header would
be redundant in the 200 OK response.

Waiting for some expert intervention.. :)

Regards,

[sandip gangakhedkar]

Hi Satya,

Thanks for the reply..didn't locate that table at first :)

Regards,

Sandip

On Fri, Aug 7, 2009 at 7:17 PM, T Satyanarayana-A12694 <

Post by T Satyanarayana-A12694
The RFC does mention this. In table 2, on page 162.
Header field where proxy ACK BYE CAN INV OPT REG
___________________________________________________________
Contact 2xx - - - m o o
regards
Satya T
------------------------------
gangakhedkar
*Sent:* Thursday, August 06, 2009 8:16 PM
*Subject:* [Sip] Contact header in 200 OK
Hi all,
I'd like to know if the Contact header is mandatory for a 200 OK response
to an INVITE request.
The RFC doesnt explicitly mention anything in this regard although a 200 OK
is mandatory for a REGISTER request.
If the originating endpoint receives the Contact header in the 180 Ringing
response (which I assume is mandatory), then it knows the location of the
remote endpoint, in which case the Contact header would be redundant in the
200 OK response.
Waiting for some expert intervention.. :)
Regards,
--
Sandip Gangakhedkar
Mobile:[phone]
Office: [phone]
Profile: http://www.linkedin.com/in/sandipg

[Goyal, Devki]

Hello Sandip
Why do you say that RFC doesn't talk about Contact for 200 OK response of INVITE?
It says that Contact header is mandatory for INVITE response only.


Header field where proxy ACK BYE CAN INV OPT REG

Contact 2xx - - - m o o



For OPTIONS, REGISTER it is optional and for rest of the messages (BYE, CANCEL ) it is forbidden.



Regards

Devki


________________________________
From: sip-***@ietf.org [mailto:sip-***@ietf.org] On Behalf Of sandip gangakhedkar
Sent: Thursday, August 06, 2009 10:46 AM
To: ***@ietf.org
Subject: [Sip] Contact header in 200 OK

Hi all,

I'd like to know if the Contact header is mandatory for a 200 OK response to an INVITE request.

The RFC doesnt explicitly mention anything in this regard although a 200 OK is mandatory for a REGISTER request.

If the originating endpoint receives the Contact header in the 180 Ringing response (which I assume is mandatory), then it knows the location of the remote endpoint, in which case the Contact header would be redundant in the 200 OK response.

Waiting for some expert intervention.. :)

Regards,
--
Sandip Gangakhedkar
Mobile:[phone]
Office: [phone]
Profile: http://www.linkedin.com/in/sandipg

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[Dale Worley]

Post by sandip gangakhedkar
I'd like to know if the Contact header is mandatory for a 200 OK
response to an INVITE request.
If the originating endpoint receives the Contact header in the 180
Ringing response (which I assume is mandatory), then it knows the
location of the remote endpoint, in which case the Contact header
would be redundant in the 200 OK response.

It would be redundant, but 1xx responses are (by default) not reliable,
so the UAS cannot depend on the UAC receiving the 180.

Dale


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