Re: [Sip] RFC 3261 - 16.10 (CANCEL processing in a Proxy)

[Iñaki Baz Castillo <[e-mail]>]

2011/4/19 Vijay K. Gurbani <[e-mail]>:
> However, I don't think that rfc6026 says much about whether or not
> to generate a 481 to a CANCEL if the CANCEL does not match a pending
> transaction.

Right, it says nothing about CANCEL.



>  So go crazy and generate it at a stateful proxy;
> from the viewpoint of the UAC, it did receive a final response
> for the CANCEL.  It may well never receive a final response
> for the INVITE if the proxy
>  implements rfc6026
>    AND the proxy crashed after sending the INVITE
>      AND the proxy did not store transaction state in persistent store
>        AND the proxy was promptly brought up and was presented with a
>        200 OK (INVITE) that did not match pending transactions

AND since the UAC would never receive the 200 it would not send the
ACK, so the UAS would terminate the dialog (sending a BYE) after ~32
seconds, which is "acceptable" (in the context of a crashing proxy).
:)


-- 
Iñaki Baz Castillo
<[e-mail]>