Dialing 384k vtc calls first 3 channels connect dialing outbound then fail. No active alarms or alerts on the device.

[goryals]

Dialing 384k vtc calls first 3 channels connect dialing outbound then fail.  Inbound VTC calls connect with no issue.  No active alarms or alerts on the device.

System placing calls is a Polycom RMX 4000 that is showing all circuits active with no alarms.

What is the best way to troubleshoot?

[Anonymous]

Thank you for using the ADTRAN Community Support Forums.

I would verify that if you only use 3 channels, the call stays up just fine. If this is the case, then try 4 channels, and continue to step up one channel at a time until it breaks. If the BONDING negotiation agrees to 6 channels, and anything less is all that connects, then the call will fail and be torn down.

You can set up logging of events under SYSTEM CONFIG in the EVENT LOGGING. You can set ISDN EVENTS to INFO as well as the IMUX MODULE (IMUX is the bonding module). You can view these events under SYSTEM STATUS in the EVENT LOG. (CLEAR SYSTEM EVENT LOG will erase the log so you can start fresh.) This will give you an over-view of what is happening. If you need more detail, you can set the ISDN L2 FORMATTED to INFO as well, but if you do this, you'll need to set up a SYSLOG SERVER to capture the data, and configure the ATLAS to send the Syslog to the server under SYSLOG SETUP. The ATLAS has a fixed Event Log size and anything more gets pushed out to make room for the new events, and the ISDN L2 FORMATTED messages are extremely verbose.

If the ISDN calls are failing you'll need to find out if it is on the ATLAS side, or the destination side having the problem. You can try calling another location, if that is successful, then it is either the destination, or somewhere in the network.

Hope this helps,

Patrick

[goryals]

Thank you Patrick.  they do have the same issue when they dial other sites.  They also have two different sets of ISDN circuits and when they use those they get the same issue.  They can make make outbound calls up to 128 successfully. When they dial to my bridge I can see the first 3 channels connect so they could most likely connect at 192. 

If this is on the Adtran side what could be the issue?  there are currently no alarms on the from panel of the box. Where can we look in the menu for an answer?

[Anonymous]

The first thing to look at is the PERFORMANCE of the T1/PRI interface under the modules. Verify there are no errors, as errors on the circuit can cause issues with Bonding the channels. If there are no errors, then you should set up the logging events as I had mentioned before. You can leave the ISDN L2-FORMATTED at minor, but you definitely want ISDN EVENTS and IMUX MODULE set to INFO so you can verify the correct number of channels are being "reserved" for the call, and that there are no "failed" dialed numbers (BUSY, UNASSIGNED NUMBER, etc.). The IMUX syslog will also show if one of the Bonding Timers is expiring during the setup.