AW: [Users] Declined INVITE invokes multiple Decline's at Proxy

Augustin, Andrew (external) Andrew.Augustin at external.t-mobile.de
Thu Jul 13 15:43:23 CEST 2006


Hello Daniel,

Thank you very much for your tips. 

You are right. The ACK did not match the dialog - under this particular scenario there was an inconsistency between the branch, to, and from tags. 

Hello All, 

I have further questions related to this topic and routing of 'locally generated' ACKs...

-  How does OpenSER distinguish between 'locally generated' and 'end-to-end' ACKs?

-  How does OpenSER know when a 'locally generated' ACK closes the transaction (e.g. Decline reply) that it is involved in? 

-  Does openser allow the modification of the Route header in a 'locally generated' ACK and usage of TM's t_relay method to relay this ACK? Or is this prohibited so that only OpenSER is allowed to automatically route locally generated ACKs? 

Best regards,
Andrew 



-----Ursprüngliche Nachricht-----
Von: Daniel-Constantin Mierla [mailto:daniel at voice-system.ro] 
Gesendet: Mittwoch, 12. Juli 2006 16:32
An: Augustin, Andrew (external)
Cc: users at openser.org
Betreff: Re: [Users] Declined INVITE invokes multiple Decline's at Proxy


Hello,

seems that the ACK does not match the dialog, thus the decline reply is 
retransmitted. The network trace (ngrep) will help to spot more.

Which of Proxy-1..3 is OpenSER and how the INVITE is routed? looking at 
the reply path, A seems to talk directly with proxy 2, but it is not 
right since the decline reply is sent back to A from Porxy 1. Or you 
didn't presented the full trace?

Cheers,
Daniel


On 07/12/06 14:26, Augustin, Andrew (external) wrote:
>
> Hello,
>
> I am using openser v1.0.
>
> I have a problem with the following SIP scenario with openser:
>
> - A invites B to a call session, B declines the invitation
>
> The message trace shown below is just part of the message trace
> produced for the above scenario displaying message frames in sequence 
> F43, F44 ... through F64
>
> Initially everything works as expected: INVITEs, Trying (100) and
> Ringing 180 messages are routed correctly from A to B and from B to A 
> via the intermediate proxies (this is not shown below). While still 
> 'Ringing', B decline's the call (sends a Decline message) message: F44 
> in trace below. This also initally routes OK.
>
>
> But the call flow for this scenario is expected to terminate at
> message: F55 once the 'Decline' has routed its way back from the 
> B-Party to the A-Party and a final 'ACK' is sent by the A-Party to the 
> previous proxy: Proxy-1.
>
> But what actually occurs is that openser running on Proxy-1
> automatically resends a 'Decline' at message F56 identical to the 
> 'Decline' it first sent at message F46. This in turn prompts further 
> ACKs and 'Decline's until it finally times out at message F107 (not 
> shown below).
>
> It appears that openser saves the original message and attempts to
> retry/resend the 'Decline' message when prompted by an ACK. This 
> continues for several cycles with ACKs and Decline's being sent and 
> received around the system until a timeout occurs.
>
>
> The above behaviour also occurs for the following scenario:
>
> - A invites B to a call session, B responds with a Busy
>
> Can you help me to:
>
> - understand what is going on
> - terminate what appears to be an open 'transaction' for the 'Decline'
> and prevent further 'Decline's and ACKs being sent around the system.
>
> Best regards,
> Andrew
>
> --------------
>
> A-Party         Proxy-1         Proxy-2         Proxy-3         B-Party
> 10.1.195.134:50 10.1.195.134:50 127.0.0.1:5070  127.0.0.1:5080
> 10.1.195.208:50
> |               |               |               |               |
> |<nging 180 F43<|               |               |               |
> |               |               |               |               |
> |               |<----------------------------- Decline 603 F44<|
> |               |               |               |               |
> |               |>F45 ACK ------------------------------------->|
> |               |               |               |               |
> |               |>F46 603 Decline ------------->|               |
> |               |               |               |               |
> |               |<--------------------- ACK F47<|               |
> |               |               |               |               |
> |               |               |<cline 603 F48<|               |
> |               |               |               |               |
> |               |               |>F49 ACK ----->|               |
> |               |               |               |               |
> |               |               |>F50 603 Decli>|               |
> |               |               |               |               |
> |               |               |<----- ACK F51<|               |
> |               |               |               |               |
> |               |<------------- Decline 603 F52<|               |
> |               |               |               |               |
> |               |>F53 ACK --------------------->|               |
> |               |               |               |               |
> |<cline 603 F54<|               |               |               |
> |               |               |               |               |
> |>F55 ACK ----->|               |               |               |
> |               |               |               |               |
> |               |>F56 603 Decline ------------->|               |
> |               |               |               |               |
> |               |<--------------------- ACK F57<|               |
> |               |               |               |               |
> |<cline 603 F58<|               |               |               |
> |               |               |               |               |
> |>F59 ACK ----->|               |               |               |
> |               |               |               |               |
> |               |>F60 603 Decline ------------->|               |
> |               |               |               |               |
> |               |<--------------------- ACK F61<|               |
> |               |               |               |               |
> |<cline 603 F62<|               |               |               |
> |               |               |               |               |
> |>F63 ACK ----->|               |               |               |
> |               |               |               |               |
> |               |>F64 603 Decline ------------->|               |
> |               |               |               |               |
>
>
>
>
>
>
>
>
>
>
> ----------------------------------------------------------------------
> --
>
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