FE MBSY? 2

[jneiberger]

We had a weird problem recently and I'd like to find out more about it. We have a QSIG T1 between an 81C running Succession 3.0 and a Cisco IPT system (CallManager 4.1(3) and a Cisco 3825). For some reason, the PBX was showing the first nine channels as FE MBSY, but CallManager thought that all 23 channels were available and idle. I did a Google search on "FE MBSY" and saw a Tek Tips post from johnpoole that suggested going to ld 96 and toggling the D-channel service messages. They were disabled, so we enabled them. That didn't help, but turning them back off seemed to have resolved the problem.

I have no idea what these messages do, and neither does the Nortel guru that was helping me. What do these do, and why does togging them help this problem?

Thanks!
John

 

[johnpoole]

service msgs are used mostly when the loop comes up.. far end busy is a cisco problem 99 times out of 100.. i had the same problem on both ccm's after a recent upgrade.. did a shut no shut on the cisco end and they cam up clean.. i did a rcnt in ld 60 before i bounced the ccm end

john poole
bellsouth business
columbia,sc

 

[jneiberger]

We bounced that circuit multiple times in different ways and we could never get it to clear up until we toggled the service messages. We tried resetting the gateway in software as well as physically bouncing the circuit, but the FE MBSY messages would not go away.

Weird. I guess I'll open up a TAC case if it happens again.

Thanks!
John

 

[srmega41]

Just so you are aware, the same issue also happens on PRI services. I had to toggle the message services on the PRI's into the 81 when they were installed. I left the message services off for a while, then turned them back on to see if there was an issue. Last time I checked, they were on for the PRI's in the 81C.

Try leaving them enabled and see if it causes you issues.

Scott M.

 

[jneiberger]

I'll have Courtney check that to make sure. It appears to me that CallManager supports these service messages so maybe I'll just leave them on.

I'm going to open up a TAC case just to get verification that CCM supports these messages. If TAC says that it should, we'll turn them on and see if that works out for us.

Thanks!
John

 

[johnpoole]

they can be strange, one switch i worked on had to have serv enabled on the two locals but the ld's wouldn't come up if serv enabled unless you did a ench on each channel

john poole
bellsouth business
columbia,sc

 

[jneiberger]

I opened a TAC case on this and TAC said that those service messages need to be enabled. In addition, there is a checkbox in the PRI configuration in CallManager that needs to be unchecked. It's called "Inhibit restarts at PRI initialization". It's checked by default. The combination of those two settings should keep the two systems in sync.

 

[johnpoole]

thanks for the update, i'll forward the note about checkbox but i do not always believe tach, service msgs need to be on if the pri comes up with fe or msby channels.. service msgs are only a startup function... you can read those on a good tbird, after full sync they go away

john poole
bellsouth business
columbia,sc

 

[jneiberger]

Well, it seems that we had mostly resolved our problems but I apparently spoke too soon. At our primary site with an 81C we now have only two idle channels from the PBX's perspective. CallManager thinks that all channels are idle but the PBX thinks that all but two of them are in an FE MBSY state.

We've bounced this circuit many times in many different ways, and I've even rebooted the router. So far, no luck. The circuit always comes up with the same two channels idle (20 and 21), and the rest are FE MBSY.

I'm wearing a hole into my desk from where I keep banging my head into it. :-(

 

[NTOldTimer]

I'm having this same problem with Telco PRIs. It's been taking one channel every day (sequentially) and putting it in the FE MBSY state. If you watch the D-Channel messages, they are getting used. Apparently as in the original posted scenario the CO is marking these channels as available. CO PRI "expert" claims we have a problem in the Nortel on our end. ETAS from INDIA says we should ask telco why they are putting our channels in FE MBSY.

 

[jneiberger]

I can't tell if the problem is that CallManager is sending incorrect information to the PBX or if the PBX is misunderstanding something. It's very weird. The other thing I can't figure out is that, in the current scenario, channels 20 and 21 always go IDLE but the others go into FE MBSY. What's so special about 20 and 21? It's really weird and it's bugging the heck out of me. I'm about ready to throw CallManager and the 81C into the trash. Of course, it's a rather big trash can.

 

[johnpoole]

check serv msgs.. ld 96 stat serv, usually when the loop comes up with fe problems it can be a service msg problem..

john poole
bellsouth business
columbia,sc

 

[jneiberger]

We had previously turned on SERV messages, so we just tried toggling them off and that cleared up all the FE MBSY channels. They are now all IDLE, which is correct. I guess we'll just keep an eye on them for a while.

 

[srmega41]

Oh what fun is to make two competing systems talk, OH....

Good luck,

Scott M.

 

[jneiberger]

Yes, this brings much joy to my life. :-(