[OpenSER-Devel] [Serdev] Possible bug in the tm module in the presence of packet loss/branches

[Benny Prijono]

Frankly I did not expect this. Just like (Open)SER, I also suppress
INVITE retransmission when canceling INVITE UAC (that hasn't been
responded to). I wonder where did we get that specification from.

So it looks like one more bug to fix for me too.. sigh..

 -benny

On 3/10/08, Klaus Darilion <klaus.mailinglists at pernau.at> wrote:
>  From the "sip-implementors" list - looks like Maxim is right.
>
>  regards
>  klaus
>
>
>  Robert Sparks schrieb:
>  > Part of why it does this is to deal with the case that the first
>  > INVITE the proxy sent actually got somewhere, but its response was
>  > lost. The retransmission will stimulate a retransmission of the
>  > response, letting you move forward to sending the CANCEL from the
>  > proxy.
>  >
>  > RjS
>  >
>  > On Mar 7, 2008, at 7:06 AM, Bob Penfield wrote:
>  >
>  >>
>  >> The INVITE transaction must still complete independent of the
>  >> CANCEL. So the proxy would continue to re-transmit the INVITE. If
>  >> the proxy does receive a provisional response, it would then stop
>  >> retransmissions and send the CANCEL down stream. If timer B fired,
>  >> it would send a 408 response to the INVITE.
>  >>
>  >> Note that the proxy should respond to the CANCEL with 200 OK when
>  >> it receives it since the INVITE transaction is in progress.
>  >>
>  >> cheers, (-:bob
>  >>
>  >> -----Original Message----- From:
>  >> sip-implementors-bounces at lists.cs.columbia.edu
>  >> [mailto:sip-implementors-bounces at lists.cs.columbia.edu] On Behalf
>  >> Of Klaus Darilion Sent: Friday, March 07, 2008 4:11 AM To:
>  >> Sip-implementors at lists.cs.columbia.edu Subject: [Sip-implementors]
>  >> CANCEL retransmisson question of no provisional response!
>  >>
>  >> Hi!
>  >>
>  >> Could someone help me please with this question.
>  >>
>  >> Scenario: A transaction-stateful proxy forwards the INVITE request.
>  >> The proxy does not receive a provisional response, thus starts
>  >> retransmissions. Now, the caller CANCELs the call. How is the proxy
>  >>  supposed to handle this? Does the proxy still have to retransmit
>  >> the INVITE or can it stop retransmitting the INVITE?
>  >>
>  >> From logical point of view I would think that the proxy should stop
>  >> the retransmissions, but from Figure 5 in RFC 3261 it looks like
>  >> the only way to come from "Calling" state to "Terminated" state is
>  >> waiting for Timer B fires (as there is no provisional response
>  >> yet).
>  >>
>  >> thanks klaus
>
>
>
>
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