[SIPForum-techwg] Question of SIP dialog match

[mike xu]

Hi Robert,

Thank you for your reply.
After I got the far side response (200 OK) with to-tag added, how
could I confirm that this response is for my INVITE? Call-ID and
from-tag is equal, but the to-tag is not equal since the INVITE
request has no to-tag.
Do you know that how to deal with this case? Update far side
response's to-tag into local before dialog match? Or just skip to-tag
match (only match from-tag and Call-ID) if the response is for the
INVITE without to-tag?

Best regards,
Mike

On 7/11/07, Robert Sparks <rjsparks at nostrum.com> wrote:
> Mike -
>
> The far side must add a to-tag to the responses it sends to your INVITE.
> This is how you tell responses from different legs of a forked
> request apart.
>
> RjS
>
> On Jul 10, 2007, at 9:39 PM, mike xu wrote:
>
> > Hi,
> >
> > In RFC3261 section 12 Dialogs, it said "A dialog is identified at each
> > UA with a dialog ID, which consists of a Call-ID value, a local tag
> > and a remote tag".
> > And as you know that the first INVITE request has no to-tag, in order
> > to match the 200 OK response for the INVITE, could I update the to-tag
> > in 200 OK response into my local INVITE's to header? If I it was
> > updated then the dialog could be matched without any problem,
> > otherwise the dialog couldn't be matched since the first INVITE's
> > to-tag is NULL. Does this operation comply with RFC3261?
> > Would you like to give me any suggestions on such dialog match
> > problem?
> >
> > Thanks in advance,
> > Mike
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