[asterisk-ss7] Some sessions hangs. Is it possible with SS7

Jacob Tinning tinning at sifira.dk
Sun May 14 23:52:33 MST 2006

On Fri, 12 May 2006, Anton wrote:

> Does anyone know, if it is possible for timeslots to hang, with SS7 signalling?

If the implementation is 100% correct (according to the ITU-T spec.) it should not be posible.

> For example if REL message is missing (did not received in time by Asterisk) -
>  would the accured timeslot hang (be active on Asterisk side, but
> released in the TELCO side?)

The 'release' procedure is this: A REL is sent to the other side, and if a RLC is not received
within T1 seconds the REL is retransmitted (and T1 restarted). This
cycle continues until a RLC is received. If a RLC is still not received
within T5 seconds, the timeout-interval is changed to T5.

In chan_ss7, T1 is 30 seconds and T5 is 600 seconds.
So chan_ss7 will end up, retransmitting the REL every 600 seconds - forever (if it doesn't receive a RLC)

> I've strange issues with one of my telco's. The sessions just timed out,
> and released by the Asterisk itself, since there is 3600s duration limit.

Well this is a little strange, since there is no timer in chan_ss7 which is setup for 3600 seconds (1 hour!).

> Any help is highly appreciated!
> ,"SS7/15","IAX2/axsoftsw1-16389","Hangup","","2006-04-21 23:04:54","2006-04-21 23:05:00","2006-04-22 00:04:59",3605,3599,"ANSWERED","DOCUMENTATION"
> ,"SS7/19","IAX2/axsoftsw1-16392","Hangup","","2006-04-21 23:05:23","2006-04-21 23:05:29","2006-04-22 00:05:28",3605,3599,"ANSWERED","DOCUMENTATION"
> ,"SS7/11","IAX2/axsoftsw1-16393","Hangup","","2006-04-21 23:46:00","2006-04-21 23:46:07","2006-04-22 00:46:07",3607,3600,"ANSWERED","DOCUMENTATION"
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --

Can you try to dump the ss7 trafic and post it on this list ?

Ast*CLI> ss7 dump start /tmp/anton.dmp both lssu msu
. <wait untill it happens>
Ast*CLI> ss7 dump stop

Mvh. Jacob

Jacob Tinning
System Developer                                           SIFIRA A/S

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