[SIPForum-techwg] Question of SIP dialog match

[mike xu]

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