Hi,

consider INVITE was cancelled before getting _any_ reply to it
(i.e. even 100 wasn't got) and top logic level timeout requires to
stop this call. RFC3261 doesn't list cancelling as reason to make
any change to INVITE transaction logic; so TU needs to continue
resendings of initial INVITE until timer B explodes or any reply
to INVITE is got (and here cancelling can start, sending CANCEL if
provisional reply is got and BYE if 2xx is got). This is
excessive, confuses admins and network analyzers, create race
conditions... My question is: what are side effects of solution to
stop retransmission of initial request (i.e. timer A), while
keeping all rest of logic (timer B, state machine with processing
responses...)? I see only advantages: if remote party is down, no
useless packets will be generated; if there were network failure,
as top-level logic already switched to another destination or even
stopped the whole call, so the probability to connect call which
is already useless is reduced. But maybe I missed something?

-- 
Valentin Nechayev
PortaOne Inc., Software Engineer
mailto:[EMAIL PROTECTED]
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