[Users] Re: [Serusers] Handling CANCELS when a UAC doesn't answer and t_relay has maintained state

Evan,

The bug you describe is already fixed in OpenSER 0.9.4 (see the news section "proper forking support in TM")- give it a try and see if it fixes your problem.

regards, bogdan

Evan Borgström wrote:

Hello All,

Looking for some input if anyone else has run into this situation 

and/or figured a way around it.

• Call comes in from PSTN gateway to a local user

• SER finds the user in the location table and t_relay pushes the

request off to them

• The user is behind an ACL and is not sending keep-alives (yes I know

the client is broken) so the INVITE never makes it to them and hence no 180/183 Ringing message comes back

• PSTN user gives up and hangs up the phone after 3 seconds of no ringing

• PSTN gateway forwards the CANCEL message in and SER cancels the branch

• However since t_relay is stateful and re-tries transmissions the

INVITE is sent another time or two

• Finally the connection times out and the failure_route set for the

t_relay kicks in and the INVITE gets pushed off to the voicemail server.

• Voicemail server OK's the INVITE and starts retransmitting the OK

over and over and over since the PSTN GW doesn't ACK the OK since it knows that call-id as being cancelled.

So, should I handle cancel's a little more explicitly by doing 

something similar to:

if ((method=="CANCEL") && (t_lookup_request())) { t_release(); };

What side effects, if any, would this cause? Is there a better way 

to handle it?

Thanks, -Evan

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