ISDN trunk periodically drops

[vitalikjon]

Colleagues, good afternoon!
We observe an unpleasant situation with the isdn trunk with the provider. Somewhere a week, at a random moment, calls no longer go, what we see in the trace:
| tei: 0 <<<< message sent : REL COMP [5a] Call ref : 10 be
|____________________________________________________________­__________________
|
| IE:[08] CAUSE (l=5) 81 e6 33 30 33 -> [e6] RECOVERY ON TIMER EXPIRY

At the same time incoming calls pass, but we are not heard by the opposite side.

Everything is restored when this message arrives in the trace.

| (079647:044427) Physical-Event :
| long: 21 desti: 0 source: 0 cryst: 1 cpl: 6 us: 0 term: 0 type a5
| tei: 0 >>>> message received : RESTART [46] Call ref : 00 00
|____________________________________________________________­__________________
|
| IE:[79] RESTART_IND (l=1) 86
|____________________________________________________________­__________________

____________________________________________________________­__________________
| (079647:044428) 1055: Send_IO1 (link-nbr=1, sapi=0, tei=0) :
| long: 21 desti: 0 source: 15 cryst: 1 cpl: 6 us: 8 term: 0 type a5
| tei: 0 <<<< message sent : RESTART ACK [4e] Call ref : 80 00
|____________________________________________________________­__________________
|
| IE:[79] RESTART_IND (l=1) 86
|____________________________________________________________­__________________


For 15-20 minutes everything works fine, and it is constantly repeated.
There is no hope for the provider, they just shrug their hands and say that these are anomalies.

Please help, can anyone faced with such glitches, and much more to lead the search for solutions.

[fery_s]

as i remember when "RECOVERY ON TIMER EXPIRY" alarm occur , you must set "Specific EI status for GSM" to "True" in the following path:
System/ Other System Param/ System Parameters/ Specific EI status for GSM
and also there are some bugs in some release that cause it and make t2 trunk frozen