Outcalling weirdness

[gregarican]

Since this is the first time in my career I've encountered this oddity, just wanted to bounce the scenario off the experts here. This past Friday for a little over an hour we ran into the following oddness.

When trying to dial an outside number, after hitting 9 on our Merlin Legend R7.1 we got a dial tone. But dialing any outside phone number resulted in a fast busy. I verified that it wasn't a case we were maxing out our calling capacity.

During this time we were able to receive inbound calls, however. When I opened up a ticket with telco, but the time they picked up the ticket things were fine. I checked the Merlin error logs and there wasn't anything showing along these lines. The 100D board showed a Yellow On, the Red and Green were off. A few minutes after resetting the board things coincidentally were fixed.

Telco pulled PM logs and said everything looked clean during this timeframe. I just wonder if it could've been either the Merlin processor board or the 100D. In the past when I've had equipment issues on my end it's all or nothing. Not a case when inbound calls would work while outbound ones wouldn't.

Any ideas?

 

[merlinman]

For what ever reason, you had a small glitch with your processor or T1 module or at the other end.

If you reset it and it went away, then most likely it was just a computer glitch. The "nature of the beast" as it were.

The system may or may not log an issue at that time.

It could have been something as simple as a really fast power hit that caused this.

http://home.comcast.net/~merlinman

 

[gregarican]

Yeah, that was strange. We could dial internally and the dialed digits were intepreted fine. Just these outbound calls threw back the fast busy. The telco end comes in as a VoIP circuit, but really is two bonded T1's that have to be broken out somewhere on their end to hit the PSTN.

Just crossing my fingers that the old Legend isn't finally fading out after so many years of service. I do have spare boards for most every thing in it, so there's some consolation.

Thanks for your reply!

 

[merlinman]

As far as the old Legend "finally fading out after so many years of service" they can be kept going for a very long period of time, and quite inexpensively also with all the parts still available at such reasonable prices.

I would discourage going with the new VOIP Telephone systems if the Legend still meets the need. (Of course I am more than a little biased toward it)

But either way, it should work just fine for almost forever.

I don't like VOIP Feeding the Legend because you are no longer able to dial in and do any programming if VOIP is all you have.

http://home.comcast.net/~merlinman

 

[SYQUEST]

With the bonded DS1s and all this other behind-the-scenes VOIP stuff, you never really know what kind of "bit twiddling" is happening that could cause that sort of condition. But I would bet some communication got scrambled on the DCH and the Legend was not happy. Without DCH nothing happens on PRI!

....JIM....

 

[papagigo1]

"bit twiddling" I'm going to steal that phrase, hope you don't mind.

Merlinman is correct, plus you can install it and forget when grounded properly. I have MLX phones working 3500 feet away, in a high lightning area with no down time.

just my $.02,
Mike

 

[SYQUEST]

Mike,

I believe it is in the public domain, so no problem there! I think it is very appropriate for what goes on in the clouds these days! It is kind of an off-shoot of "thumb twiddling" in relation to cpu timing loops or counters, that is how I derived the phrase.

....JIM....

 

[gregarican]

Okay, here's the latest incident. Here goes...

We have a satellite location connected to this one location I mentioned above. This remote branch has a Merlin Magix r2 with an INA board splitting out the voice and data, as coming through a private T1 provisioned for tandem networking.

Yesterday when calling the remote branch there was no ringback tone. Calls really did ring into them but the main location couldn't hear the remote branch. Calling from a cell phone to the remote branch had the same behavior. The incoming caller couldn't hear a ringback tone or their connected party. Although the remote location could hear them. The circuit didn't show any errors looking at the stats while this was going on.

First I reset the main location's 100D board. No luck. Then I restarted the main location's Merlin Legend. Still no luck. Then I reset the remote location's INA board. Still no luck. Finally I restarted the remote location's Merlin Magix. This seemed to have fixed the issue as calling to the remote location worked fine.

What's frustrating is that I cannot get telco to have a tech look at the circuit while I'm looking at my equipment. But I'd think since I'm providing PRI signalling (over the fractionalized portion for voice) and whatnot. The data portion of the INA was also unavailable during the outage as well between the sites.

Any ideas? I'm starting to worry a little, since two significant outages in a week's time is very unusual :-(

 

[SYQUEST]

Have you checked the telco NIU? See what LEDs are on or flashing. You might tell us the make/model of the NIU. If it is an HDSL circuit design, there could be a problem with one of the local loops. In the past when having problems on DS1 circuits of the HDSL design @ the HDSL level, you WON'T get ANY DS1 alarms reported on the DS1 from the HDSL ever. The only way you will get one is if the HDSL loses power! Telco needs to pull stats on the on the HTU-R and the HTU-C modules. I know you can connect locally to the HTU-R (NIU) with a serial connect to a VT100 or equiv. It may or may not be passworded. You can also try power cycling the NIU by unplugging the NIU for a minute and plugging it back in.

Who is the service provider?

This is one of the gotchas of using HDSL instead of a repeatered copper DS1 design, the old way, unless it is fed from an M13 mux or other type of remote terminal or DLC.

....JIM....

 

[gregarican]

Thanks for the reply. I checked the NIU the when the first incident occurred and it was all green. No alarms indicated whatsoever.

Our telco provider is XO Communications, and when they pulled the PM logs after the circuit was up on both occasions supposedly things looked clean. Of course I haven't been able to get a telco tech on the phone during the outages to both compare notes.

Just really odd that two different systems experienced strange behavior, on two different circuits to boot!

 

[gregarican]

Checking this point to point now on the Merlins I see around 20 MIS and SLP events per hour. The Legend is set to local clock and the Magix is set to loop clock. The Magix says Active: Yes, but the Legend says Active: No when I look into Maintenance --> Slot --> Clock. Both of them show PPM: 000.

When I call between locations I do hear the telltale clicking and popping noises periodically. Should I reset the Legend's 100D again? The circuit is up, just running dirty...

 

[SYQUEST]

That would indicate a clocking problem, so you want to verify your clock sources. Remember, that you should have a single clock source, the PSTN DS1 in your case, and the point-to-point DS1 gets its clocking from the Legend referenced to the PSTN. NO clocking is inserted from Telco on point-to-point DS1s. You probably want to verify set options per the Network Reference document to make sure your clocks are in agreement. There is the possibility that one of the 100D or INA modules is failing internally or starting to fail. You could run the maintenance tests and see what results you get, or change the modules with spare ones.

....JIM....

 

[gregarican]

Good points. I will look to do this maintenance testing of the boards before our locations open for business. So far I don't think that the remote location's fax transmissions are failing so the clocking cannot be that off, correct? I do have spare boards so in a pinch I could swap them out as well.

Thanks for the reply!

 

[SYQUEST]

Do all the outside calls go through the Legend to get to the PSTN, or does it have local trunks that the fax could be using?

....JIM....

 

[gregarican]

All calls go through the Legend to get to the PSTN. The only POTS lines at the remote location are 5 for backup in case the point to point go down, remote access, etc.

Right now looking at the Legend it shows 0 MIS and 29 SLP for the previous hour. I'll try to test out the Legend 100D and the Magix INA tomorrow morning and see how it goes...

 

[gregarican]

So far things seem to be running smoothly. No calling issues from either system. When I look at the stats on the boards both sides show 15 SLP's per hour as a constant. No MIS or any other indicators, however. From what I can tell making test calls I don't hear any popping, cracking, etc. and all fax transmissions seem to work fine between the sides of the private circuit.

For now I think we should be okay, and am glad I still have two spare boards on hand just in case!