[OpenSER-Users] "noisy_ctimer" parameter in TM module

Jiri Kuthan jiri at iptel.org
Mon Mar 3 20:38:41 CET 2008


At 20:17 03/03/2008, Ovidiu Sas wrote:
>On Mon, Mar 3, 2008 at 2:06 PM, Klaus Darilion
><klaus.mailinglists at pernau.at> wrote:
>> Jiri Kuthan wrote:
>>  > At 12:44 29/02/2008, Klaus Darilion wrote:
>>  >> I vote for "remove" and have it "on" always.
>>  >>
>>  >> I never saw a reason for this parameter
>>  >
>>  > Maybe underdocumentation is the point why many folks seem to be excited
>>  > by removal :-)
>>  >
>>  > Well -- with RFC2543 it could have been quite inconvenient for you to
>>  > figure out that after say 90 seconds of early media (say on my favorite
>>  > callee, German imigration office) you will be disconnected by a proxy
>>  > server while stil in hope someone would answer for you. This is
>>  > particularly annoying if the server in the path is playing a special
>>  > purpose role (such as load-balancer) and surprises rest of the world
>>  > with a CANCEL. this has been a real trouble in the field.
>>  >
>>  > This obstacle should be in theory removed in RFC3261 which allows 18x
>>  > to extend the proxy server timer.
>>  >
>>  > (It goes back to the INVITE transaction as whole being misconcepted in
>>  > the SIP protocol, but that's frankly not worth fixing now.)
>>  >
>>  > With that, my recommendation is to check behaviour of existing gateways
>>  > before doing changes. (otherwise noisy_timer is undoubtably a confusing
>>  > hack which if absent makes things simpler)
>>
>>  I think there is no easy way to solve this. A workaround would be to
>>  increase the fr_inv_timer in the reply route (e.g. after getting a 183
>>  response) - but I fear this would be difficult to implement.
>>
>>  regards
>>  klaus
>
>Another workaround would be a timeout_route 

Yes -- actually I think it would be a   clean step to separaate failure_route
in failure_route handling negative replies and timeout_route. (cc-ing serdev
thus too). Reseting the timer from there to comply to RFC3261 or executing
some service (all kinds of haunting) or going stateless if desirable and
possible would be few examples of meaningful actions to be done from there.

>and there the admin can
>take a decision:
> - drop the transaction, disable CANCEL generation and switch to stateless mode
> - re-arm the timer and stay in statefull mode
>
>Like this, the script has full control over the behavior of the server
>and no under the hood tricky mechanism is involved.

I like explicit control in this case esthetically better too.

-jiri


>BTW: I would love to see this implemented for dialog timers :)
>http://sourceforge.net/tracker/index.php?func=detail&aid=1892203&group_id=139143&atid=743023
>
>
>Regards,
>Ovidiu Sas



--
Jiri Kuthan            http://iptel.org/~jiri/





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