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Intermittent fast busy on Atlas 550


I have a customer that is bringing in 2 PRI's (Frontier) into their Atlas 550, and then mapping them out as PRI to their Avaya PBX and Fax server. Recently they have been getting an intermittent fast busy on incoming calls. So far they have reached out to their provider (Frontier) and the PBX(Avaya) vendor. Of course both are saying its not them. I have not seen their configuration, and only know that everything was working up to a week ago.  The current IT director has no experience with the 550 either, and called me as the local partner looking for help. I'm heading over there tomorrow afternoon and would love to have an idea of how to troubleshoot this problem. Unfortunately the 550 is out of warranty so getting a service contract might not be an option. If all else fails I will pay for service by the 1/2 hour.

Can you provide a way for me to log/troubleshoot this issue? I am not very familiar with the 550, but have one in our test facility that we use to mimic PRI traffic when testing TA900's. I did see a post from a few years ago that mentions changing from Linear to Circular hunting. Not sure if this is an option or not but thought I would mention it.Thank you in advance for any help you can provide! If you need any other information please let me know.



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Re: Intermittent fast busy on Atlas 550

Hello Matt,

   If they are doing PRI to PRI, I assume they are using the DIAL PLAN, otherwise they could just use T1 CSU ACE. If they are using the DIAL PLAN, I assume they are either changing the SWITCH TYPE (Switch Protocol) or routing by number dialed - or again, the CSU ACE would be a more cost efficient solution.

The first thing to look at is to verify all the PRI circuits are running "clean." You can look under the MODULES and then look at the PERFORMANCE statistics to see if any of the interfaces are accumulating errors. If they are "clean" then you will probably have to monitor the PRI messages through the ATLAS and look for the calls that are getting the fast busy and try to find out, A) if the calls are making to the ATLAS, B) if they are being sent to the Avaya PBX, and C) what the Avaya is sending back. To do this you'll need a Syslog Server program and you'll need to configure the ATLAS to send its logging to the Syslog Server. In the ATLAS you'll need to configure under SYSTEM CONFIG, and EVENT LOGGING the ISDN L2 FORMATTED events to INFO. This will give you all the ISDN messages for all the interfaces (I'm afraid there is not a way to isolate it to a specific interface).

You can look at the following document: Using the Adtran Utility Syslog with the Atlas, and while the "Adtran Utilities" are no longer supported, any Syslog program will work, and configuring the ATLAS is the same.

Hope this helps,