Inter-Tel, NI-2 and B Channel Service Messages 1

[HarrisD1200]

I'm trying to figure out if Inter-Tel supports B Channel Service Messages on PRI's running NI-2 variant or not. Also called SERVICE and SERVICE ACK in Q.931. I work in a CLEC on a DMS-500, and need to know whether to turn them ON or OFF for Inter-Tel PBX's. TIA!

 

[ISDNman]

If in doubt I would turn them off. That is just a hunch on my part.

I know that the Netacess cards for instance ignore these messages.

I did not realize this was configurable on the DMS. How do you turn it off? Just might help with a problem I am seeing with a DMS-100 in CA.

Good luck, and thanks

 

[HarrisD1200]

Thanks for the advice, that will be my last resort. I'd feel much better if I can get a YES or NO on them, rather than turning them OFF and waiting for a trouble ticket to appear! ;-)

As for how to turn them off in the DMS-100 and DMS-500, just add NO_BCH_SERV to the SERV tuple in Table LTDATA. It is instantaneous, no reset of the D channel or B channels is needed. Unfortunately, by default, they are turned ON. This setting is only applicable to NI-2 Variant.

The problem indication that lead me to ask the question is that the customer will occassionally have problems dialing out of the switch, even tho my DMS shows plenty of IDLE channels. Occassionally, we would also get a complaint of people attempting to dial in and getting an "All Circuits Busy" (or equivalent message), again with IDLE channels.

On a customer with a NEC 2000 IVS, we were able to "catch" the system in this mode. We had 24 people trying to dial out, and there were still 10 or so IDLE channels. I added NO_BCH_SERV, and instantly, every channel started processing calls. This lead me to question whether other systems didn't support them or not.

Sorry for the long windedness, hope this helps on your problem!

Harris D1200

 

[ISDNman]

Harris D1200,

THANKS!! This is exactly the sort of problem we have seen on a DMS-100 with NI-2. We had a hunch it had to do with the fact our gear did not handle the Service messages.

Can't wait to talk to the folks at SBC and see if this clears up the problems.

 

[HarrisD1200]

With luck, this change will solve your problems. I have yet to find a manufacturer (and there are quite a few whom I haven't heard from yet) say that they support B Channel Service Messages. So far, NEC, CISCO, Altigen, Iwatsu, and Adtran have all confirmed that they don't support these messages, so they should be turned OFF in the DMS. I'm still looking for input from Mitel and Inter-Tel (covers about 60% of my NI-2 customers), Avaya, Samsung, and a few others. But, my bosses like your idea, come next Tuesday, we are turning them OFF for everyone, and will deal with any problems on a case by case basis.

I just can't figure out why Nortel has them defaulted to ON, most Nortel CPE equipment (but not all) doesn't even support them.

Luck to ya! HarrisD1200

 

[ISDNman]

The symptoms you describe could be describing our customer's situation. I emailed them and suggested they contact the LEC and have this change made. I'll let you know, but I am relieved and optimistic to to have learned about this.

I haven't looked at the standards recently, but when I did it seemed to me that if the CPE ignores the service messages this should not be a problem. That being the case, combined with the quite random nature of the problem, seems to me that this may actually be a problem with the DMS.

Of course as long as there is a solution it does not matter much. We have a detailed PRI provisioning sheet for our users, so if this works we'll just add this to it.

Thanks again, I'll post results once I have some.

 

[HarrisD1200]

Well, the only other thing I would look at is what hardware the LEC is using for this NI-2. Presuming that NO_BCH_SERV doesn't fix the issue, we've had limited success moving customers from SPM's to DTCI's in the DMS-500. No one knows why, but this change will occassionally solve odd problems. I have no idea what hardware your customer is currently on, or if the LEC can move it if it's a SPM, but just another thought. ....HarrisD1200

 

[ISDNman]

Too early to say for sure, but it has been a week since we has SBC turn the Service messages off, and so far no complaints from the customer. It has been long enough to say this has not made things a lot worse, but not long enough to say the problem is solved.

In addition to the exact problem described by HarrisD1200, we also have had a problem on these particular PRIs with coming back up after a reboot. If the line is not in Red Alarm for about 5 minutes, all the B channels do not reliably come back up. When looking at the protocol traces and the standards it would appear this is due to the fact the switch is sending service messages in an attempt to see if calls can be recovered. We hope that disabling the Service messages may solve this problem as well.

Since this is a secondary problem for the customer I did not have him test this problem - I had him reboot in his usual way to prevent that problem (e.g. unpugs the PRI, reboots the syustem, and replugs the PRI after 5 miutes)after the changes were made to the DMS-100. If he's still not having problems in two more weeks I'll have him do a normal reboot and see if that problem might be solved as well.

Thanks again for the information sharing. Good luck hearing form Inter-Tel.

 

[HarrisD1200]

I appreciate the information about the reboot, that is not something I've seen done. Very good information. And being cautious is good on this problem, the day you decide it is truly fixed will be the day it comes back.

 

[ISDNman]

Well, it has been nearly 3 months and the customer has not seen this channel availability problem once in all that time.

I will be adding a warning to our provisioning notes about this and will consider the case closed.

I need to contact the customer and see if this also solved the problem we had after reboots.

HarisD1200, any luck getting information on this from other vendors?

You can put on your list that the Telos Systems Series 2101 does not support B Channel Service Messages, just in case you ever run across our system.

Thanks again for being willing to share this information. You've really helped us take care of our customer and for that we are gratefull.

Cheers

 

[HarrisD1200]

I'm thrilled to know that your customer is up and running. That is great news in that it gives me more data on the problem. As for other manufacturers, all the big ones won't talk to me unless I have a contract, which for most, I don't. I have only the list posted in February, and one caveat when working with Nortel equipment. We had the identical problem with a 0X32 Nortel, but turning off the B channel service messages did not help. We had Nortel PBX and Nortel DMS on a conference call, but that didn't resolve anything. Each blamed the other, and it went no where. What we ended up doing was changing selection sequence to Round Robin on both the 0X32 and the DMS, and the instances stopped happening. To my mind, they are only masked, but we couldn't think of anything else. This will be my last post to this thread, I appreciate the feedback ISDNman. Unfortunately, I'm off the DMS now, so will have no more information. As always, I'm happy to share anything that gets our customers happy.

 

[johnpoole]

fyi, you can run service msgs nortel to nortel pbx to key but only if your running clear channel between them. as for as service msgs to a nortel pbx, that is on of off at the switchmans request. biggest problem with nortel pbx to key is the dsel prompt has to be vod past rld 24 in the pbx to work clean

john poole
bellsouth business
columbia,sc