Abnormal ISDN Drops

[PandoraLove]

Has anyone got any idea what the following means? It appears when i do a 'Display Events' command and filter it by 'Denial' and event type 1166.

1166 Abnormal ISDN drop D2=CV 514 1F
1166 Abnormal ISDN drop D2=CV 830002 1F

We're getting calls that are being cut off mid-way through a conversation. I've found which trunk it happens on, but don't know how to fix it or where to start looking - none of the Avaya documentation even touches on 1164 or 1166 Events! I am hoping that this event does have something to do with my problem.

I have found a thread which links me to a site thats in Russian, but i don't speak/write in Russian so i'm a bit stuck.

I gather that a few people get this error, but that its quite hard to rectify. BT have said that there is nothing wrong with the trunk. I haven't had any TREND testing done yet and was wondering if its worth getting that done??

Any help that anyone can give me will be gratefully received.

Regards.


Donna Nash
Senior Voice Engineer

 

[robonix]

Hi Donna

We too are facing similar problems..... Are u guys using any Multiplexers? or any Bandwidth managers?

We are assuming the problem to be with the Multiplexers for this matter.This can also happen if at all there is any fluctuation on the link which carries the Voice traffic....

If at all u get to know any thing on this Please update me.....

Regds

Robonix............

 

[europe]

I was wondering, did you guys have stable E1 links?
And just after an Upgrade to R11 sumbled across this problem...

Hoping fo an update of you ...

Please let me know if the information that was provided is helpfull.
Edwin Plat
A.K.A. Europe

 

[robonix]

Hi Europe

Thats right our Voive traffic is on an stable E1 link.This is an IPLC ckt between my country and the US.

And we dint have any upgrade.we have actually bought S8700 R11.........

any Ideas ?

Robonix.............

 

[PandoraLove]

Hello...

In answer to your question, yes, we've got stable E1 links. Guess when this problem started though - right after we upgraded to V11!

I've searched the Avaya vaults high and low for this problem but there is nothing available, (yet).

Will keep looking and if i find anything else out, will let you all know.

Cheers.



Donna Nash
Senior Voice Engineer

 

[PandoraLove]

Hello Again...

I've just managed to get hold of my 'Definity Guru' and he has said this about the 1166 Event:

'This is a network problem, not a Definity problem. The calls get dropped for no apparant reason and are reported in the Events screens as 1166 Abnormal ISDN Drop.' A bit vague i know but he told me its best for me to contact our Carrier and report it to them so they can investigate further, possibly with TREND tests. I've already tried that with our Carrier so am now going to try again.

I've been getting about 10 drops a day, from 2000 incoming calls. I've been advised that this is an 'acceptable' level as far as dropped calls go.

If i find out anything else, i'll let you know.

Donna Nash
Senior Voice Engineer

 

[anjonou]

Hi Donna,

I too have a similar problem at my site, although my E1 link is private. I will be very grateful to have any updates as soon as they are available.

Thanks.

 

[colby007]

Funny you guys should mention this but I had this error yesterday. One of the E1 circuits went out of service for 10 minutes and I found the Abnormal ISDN DROP in the events. I have look everyewhere to find anything on it but hsve failed drastically. This is only a V9 system. Someone please help.

 

[zebrabwbwbw]

Whenever I see any problems on a digital trunk I check to see if the pbx is syn ing off of a t-1 trunk or if it is on the tone clock. A t-1 will always get drops and other problems if the pbx is not syn ing off a t-1, and the correct one too. In addition, you don't want two pbx syn ing off of each other, but if u have a network, then the syncronization has to be set up so one pbx syns off of the network, and all the other pbx sync off of this pbx. Do "status syn" and "display syn". The syn source should have no errors on it when u do the command "list measurements ds1 log" and the board number. If u have errors on the syn source then the whole pbx will have problems, and all pbxs that are networked to it.
The provider aways says there is never anything wrong with their trunk. Sometimes u have to request the provider of the trunk that they have a 'stress test' done in the middle of the night when u are not taking calls.
The syn source for the pbx should have "slip detection" "yes" for the syn source and the secondary. All other boards should have "slip detection" "no". You can see this in the screen "display syn".

 

[vigia]

Hello zebrabwbwbw. Why do the other T1/E1 boards (not the sync ones) should have "slip detection" set to "no"?
What´s the influence of "slip detection" in this question?
In my company we use "slip detection" set to "yes" for all E1 boards (we´re in Brasil), and it´s very useful to detect problems with the circuits.

Thank you.

 

[PandoraLove]

Hello...

Ok guys, i've done everything that zebrabwbwbw has recommended (Some of my other DS1s had Slip Detection set to 'Yes') and have cleared all outstanding events. Incidentally, none of the DS1 error logs had any errors!

Will post a reply in a day or so once i've had a chance to monitor everything and will let you all know the outcome.

Thanx for all your help! )


Donna Nash
Senior Voice Engineer