Subject: Question about multiple 200 OK responses

From: Sunitha Kumar <[email-masked]>
Date: Mon, 17 Jan 2000 17:26:37 -0800

It is given that there could be multiple INVITEs reaching the client,
because of the proxy forking this.And, for each such INVITE reaching the
UAS, it SHOULD send a 200 OK. My question, is should each of this 200 OK
be considered for re-transmission?
And, what happens at the client receiving multiple 200 OK. Should there
be an ACK for each of it, or should just one ACK handle all of this.

Thanks much!

--
Sunitha Kumar

---

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 17 Jan 2000 18:06:26 -0500

Sunitha Kumar wrote:
> because of the proxy forking this.And, for each such INVITE reaching
> the UAS, it SHOULD send a 200 OK.

Actually, I don't think thats the best approach. I circulated a note
some time back on handling of "merged requests", as they are called.
See:

http://www.cs.columbia.edu/~jdrosen/sip/multiple_requests.txt

 My question, is should each of this
> 200 OK be considered for re-transmission?
> And, what happens at the client receiving multiple 200 OK.

THe above solution will guarantee that if it receives multiple 200 OK,
they are from different UAS's. Handling of multiple 200 OK has been
discussed on the list extensively. You should ACK each. Beyond that, the
consensus is that there is no one right approach. THe options are:

1. BYE all after the first
2. keep all; ends up being N point to point call legs that are not
bridged
3. use call control to bridge the legs together, resulting in a
conference call

-Jonathan R.
-- 
Jonathan D. Rosenberg                       200 Executive Drive
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