[SIPForum-discussion] To-tag Change

[Robert Sparks]

No, if a proxy _got_ a 200 from another branch it is required to  
forward it.

It is legal for a proxy to have the canceling policy you suggest, but  
it is in no way "usual" (its certainly not suggested
by any standard) and as I said earlier, it would break many real  
world deployment scenarios.

RjS


On Feb 8, 2008, at 2:17 PM, Manpreet Singh wrote:

> In forking scenario, shouldn't the proxy be smart enough to not  
> pass 200 when it has passed 183 from a certain endpoint. Usually in  
> forking, the proxy would CANCEL other requests once it has recieved  
> 18x for one of the requests to get out of this situation. Even when  
> 183 does early dialog, the UAC doesn't expect the tags to change  
> for that dialog. Getting different To tags would cause issues with  
> dialog identification.
>
> M
>
> -----Original Message-----
> From: discussion-bounces at sipforum.org [mailto:discussion- 
> bounces at sipforum.org] On Behalf Of Robert Sparks
> Sent: Friday, February 08, 2008 12:38 PM
> To: BIENVENIDO A 007MUNDO
> Cc: j.martinez at javeriana.edu.co; discussion at sipforum.org
> Subject: Re: [SIPForum-discussion] To-tag Change
>
> You can see a 200 with a different to-tag than you saw in the 180  
> in the real world.
> Its not that the thing emitting the responses changed the tags -  
> its that different things emitted the responses.
>
> If the request forked somewhere downstream from you, you could have  
> one branch of the fork return a 180 and the other return a 200,  
> leading to what you're seeing.
>
> RjS
>
> On Feb 8, 2008, at 11:12 AM, BIENVENIDO A 007MUNDO wrote:
>
>> Hi,
>>
>> Do you think that is possible to change "To-tag" field in a 200ok
>> message after receiving 18X message with to-tag?
>>
>> The references aren't clear neither RFC3261 nor drafts (for example
>> http://tools.ietf.org/id/draft-ietf-sipping-service-examples-13.txt).
>>
>> In draft example 2.9 (call forwarding - no answer "sequential
>> forking"), "To-tag" F5 message (180) is different than "To-tag" in
>> F13 message (200ok), otherwise in RFC3261 the session is established
>> with unique ID, this ID is composed of "From-tag", "Call-Id" and
>> "To-tag".
>>
>> My Switch doesn't accept 200ok with different "To-tag" if previously
>> has received a 180 message.
>>
>> Can someone clarify this issue please?
>>
>>  Thanks,
>>
>> José.
>>
>>
>> _______________________________________________
>> This is the SIP Forum discussion mailing list TO UNSUBSCRIBE, or edit
>> your delivery options, please visit http://
>> sipforum.org/mailman/listinfo/discussion
>> Post to the list at discussion at sipforum.org
>
>
> _______________________________________________
> This is the SIP Forum discussion mailing list TO UNSUBSCRIBE, or  
> edit your delivery options, please visit http://sipforum.org/ 
> mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org
>
>
>
> _______________________________________________
> This is the SIP Forum discussion mailing list
> TO UNSUBSCRIBE, or edit your delivery options, please visit http:// 
> sipforum.org/mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org