Brett Tate wrote:
> Race conditions exists (although not likely to occur) where the remote
> party's Contact may be updated between sending requests again with update
> auth headers. Depending upon loose routing usage, this can impact Route
> header or request-uri (see rfc3261 section 16.12.1.2).
Yeah. Between your first attempt and the 2nd, you could receive an
UPDATE that changes the Contact, or possibly that sends you a new offer.
To cover such a case, you would be better off to recompute a new request
that applies whatever change you were attempting to the current state of
the dialog. (You might find that what you want is already in effect now
and no request is needed.)
> The likely hood of such an update is hopefully small.
Small, but possible.
> If I recall correctly, some are also proposing (or "fixing" rfc3261) to allow
> such an update even if you rejected the update to Contact during the race
> condition (such as by sending a 491).
I think we cannot allow a failing request to change the target. But a
success should not be rolled back even if the containing invite
transaction eventually fails.
Thanks,
Paul
>> -----Original Message-----
>> From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-
>> implementors-boun...@lists.cs.columbia.edu] On Behalf Of M. Ranganathan
>> Sent: Monday, July 20, 2009 10:20 AM
>> To: sip-implementors
>> Subject: [Sip-implementors] Handling in-dialog challenges.
>>
>> Hello
>>
>> I have a question about how to re-originate a request for an in-dialog
>> challenge. For example, if a re-INVITE gets challenged, when sending
>> the new request with credentials, would it be correct to just clone
>> the old route (from the original request) set or consult the dialog
>> for a change in route set? Is it even possible for that route set to
>> change?
>
>
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