Jason Fischl wrote:
>
> What is the correct behavior for a proxy in the following situation?
>
> According to bis09, User A should not send the CANCEL (F6) until
> it has first received a 100 response from the Proxy. However,
> there are user agents out there that violate this.
Not surprising; it didn't find its way into bis until our big rewrite.
> My question is how should the stateful proxy behave?
>
> Should it send out a CANCEL to any targets that have already had
> the INVITE sent to them and send a 200 (for Cancel) back to the caller?
It should 200 OK the CANCEL, wait for the 1xx for any INVITEs it send,
and then CANCEL them.
> If the invite has not yet been received, (messages crossed) should it
> ignore the CANCEL?
A proxy that gets a CANCEL that it doesn't have matching transaction
state for will actually proxy it; see 16.10 of bis-09.
>
> Here is a possible call flow. F3 should not be sent until F5 has been
> received. However, we have seen several examples where this is not the
> case.
>
> User A Proxy 1 User B
> | | |
> | INVITE F1 | |
> |--------------->| INVITE F2 |
> | CANCEL F3 |--------------->|
> |--------------->| 180 F4 |
> | (100) F5 |<---------------|
> |<---------------| |
> | 200 F6 | |
> |<---------------| CANCEL F7 |
> | |--------------->|
> | | 200 F8 |
> | |<---------------|
> | | 487 F9 |
> | |<---------------|
> | | ACK F10 |
> | 487 F11 |--------------->|
> |<---------------| |
> | ACK F12 | |
> |--------------->| |
> | | |
This flow represents correct behavior for the proxy.
-Jonathan R.
--
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Avenue
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PH: (973) 952-5000
http://www.dynamicsoft.com
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