Girish,
There are no rules here. IETF only standardizes the protocol, not the
construction of stacts that support it. You are free to construct the
stack any way you, and the users of your stack, desire.
Paul
Girish Moodalbail wrote:
> Thanks Robert for the response.
>
> From your reply I understood that within a dialog if a re-INVITE is
> issued than
> the dialog layer in the SIP Stack should not populate the Contact header
> of the
> re-INVITE request. It's left to the application to add the same Contact
> header (if
> it has not changed the location) or a different Contact header (if it
> has changed
> the location).
>
> Correct me if my interpretation is wrong.
>
> regards
> ~Girish
>
> Robert Sparks wrote:
>> Both are used.
>>
>> Typically stacks layer what they offer - they have a transaction layer
>> that doesn't know about dialogs
>> and a higher layer that abstracts dialogs into things like calls or
>> subscriptions. The first thing would
>> not autopopulate the local target (in the contact). The second
>> typically allows the local target to be
>> changed, but the application has take extra steps to make it happen.
>>
>> RjS
>>
>> On Jul 12, 2007, at 2:07 PM, [EMAIL PROTECTED] wrote:
>>
>>> Hello all,
>>>
>>> I have this question on creating a request within the dialog. As per the
>>> RFC 3261, Section 12.2.1.1
>>>
>>> "Generating the Request", that UAC should add the contact header.
>>>
>>> "
>>> A UAC SHOULD include a Contact header field in any target refresh
>>> requests within a dialog, and unless there is a need to change it,
>>> the URI SHOULD be the same as used in previous requests within the
>>> dialog. " However is it a good idea to add the Contact header in
>>> the Sip
>>> stack to facilitate the application developers.
>>>
>>> 1) Are re-INVITES used predominantly to re-negotiate the media session
>>> parameters? In which case the contact header would remain same across
>>> INVITES and it would be helpful to have Contact header set by the API.
>>>
>>> 2) Are re-INVITES used frequently to inform the peer of changed
>>> address, in
>>> that case it does not make sense to add the header in the stack as
>>> UAC has
>>> to delete the header and re-add the new contact header.
>>>
>>> So my question is will it be useful/valuable to add the Contact
>>> header for
>>> Invite request in Sip stack
>>>
>>> thanks in advance and appreciate your help
>>>
>>> regards
>>> ~Girish
>>> _______________________________________________
>>> Sip-implementors mailing list
>>> Sip-implementors@lists.cs.columbia.edu
>>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
> _______________________________________________
> Sip-implementors mailing list
> Sip-implementors@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
_______________________________________________
Sip-implementors mailing list
Sip-implementors@lists.cs.columbia.edu
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
