DTI "Long Term Alarm Threshold" configurable? 1

[PhaseJitter]

We receive many alarm 42 and alarm 44 notifications: "The long term alarm threshold has been surpassed in the DTI for loss of frame" or for "the detection of Remote Alarm Indication". Our provider is telling me that the frame alignment or loss issues we are experiencing are well within spec. This seems to occur 3 or 4 times a week.

One DTI sends a yellow alarm whenever this occurs, and often does a "software" reset. Is there a programming area on a MICS 6.0 to increase the value of this parameter??

What is acceptable in terms of frame loss? My book tells me that the frame loss duration needs to be 2.5 seconds before the yellow alarm is issued.

Thanks for any help

Charles

 

[aragon]

There is a timing issue.

It could be the csu/dsu they installed is faulty.
Could be a crappy network.
Could be your services card.
Could be that you should turn off your internal csu in the Norstar.
Could be all of the above.

Try turning off the internal csu first in the Norstar.

David Brillert

http://www.williamsglobal.com

 

[aragon]

How was my information helpful?
Just curious.

David Brillert

http://www.williamsglobal.com

 

[PhaseJitter]

Thanks Aragon,

Just having somewhere else to look was helpful. I've been struggling with this for about a year now. This was a new installation, about 14 months ago. Our Service Company replaced the DTI last May, but the problem has persisted. It's always been their position, that network errors were causing the issue. No one has ever suggested the clock services card, as a possible cause. I'll be swapping out the existing "combo card" today or tomorrow.

What would result if I were to disable the internal CSU, as you suggest?

Thanks Charles

 

[aragon]

You would be relying on the clocking provided by the telco.
No harm should come to the system in fact this may solve your timing issues.

David Brillert

http://www.williamsglobal.com

 

[hawks]

Realize that the clocking and the CSU are 2 different animals. Some Telcos don't even like to troubleshoot the circuit if it has no CSU on it. You could run without the CSU (not recommended here) but with a bad clock source your T1 will go in and out of service. I noticed above that you said you were running 6.0. Well someone correct me if I'm wrong but didn't NORTEL find some timing issues with some of the 6.0 & 6.1?

 

[aragon]

Hawks correct me if I'm wrong but the csu in the Norstar is redundant as the telco typically provides a csu/dsu with every circuit (pairgain) we can turn off the csu in the Norstar without pissing off the telco.
The M1 product for example provides no internal csu/dsu and an external unit must be provided.
As for Nortel:
There were issues with 4.0
There were issues with 4.1
There were issues with 4.2
There were issues with 5.0
There were issues with 6.0
There were issues with 6.1

What else is there?
Our hands are tied and we can finger point and upgrade until pigs fly.
In the end we cannot wait for the vendors to comply with eachother because this will never happen.

Try turning off the csu (simplest option).
Also what protocol and switch type is the carrier providing?
Can they provide DMS100 protocol support?
Most of Nortel's PRI issues are related to their NI2 protocol support and things tend to work fine with DMS100.

As for the previous thread:
"It's always been their position, that network errors were causing the issue."

Can the provider elaborate?

Have you approached another provider?

Have you approached another vendor?

David Brillert

http://www.williamsglobal.com

 

[hawks]

The Telco will provide a CSU at a monthly charge but you must request it. At least that is the way it is around here, most of the time they stop at the "smart jack" and the customer takes it from there. As far as the issues with the 6.0 & 6.1 they were call timer issues on digital circuits along with some other T1 issues. So MICS 6.1 MR WI 6.05 is suppose to address the problem.

 

[aragon]

Thanks Hawks

Let's relay the info to Charles:

Charles if you open the door to your Norstar KSU you will find a software card in the main cabinet there will be some writing on it. Post what you see.
If in fact you do need an upgrade to WI6.05 you will have another issue to contend with in getting an upgrade for your Norstar.
Your vendor may be able to get a free maintenance issue from Nortel (not likely) or you may wish to purchase the upgrade (not likely due to it's cost unless this is really hurting your business). If you have a maintenance contract with your current vendor maybe they will provide as part of your contract.

Good Luck.

David Brillert

http://www.williamsglobal.com

 

[PhaseJitter]

Thanks for all the posts.

This particular circuit is used to network two sites using MCDN. South office norstar is exhibiting the problem.

Observed during event: One or no B channel available (Link Status shows 22 available)or "no lines available" when destination code is pressed.
Need to reboot KSU often to restore full functionality (~ 1/month.)

Clock source there is Primary, but it is also a slave.

Version: NA-MICS-DR 6.0 Rel 01 2003/02/26

Is it still acceptable to turn off the internal CSU if the clock there is derived?

Thanks for the tips
Charles

 

[aragon]

Did the carrier provide an external csu/dsu?

Also are the software versions at each site identical?

You should not need to reboot the entire KSU simply disabling and re-enabling the line card in maintenance should be sufficient.

David Brillert

http://www.williamsglobal.com

 

[hawks]

One other question, do you have another T1 in the system? The reason I asked is if you have one going out to the carrier it would be better to set that one up as Primary (clock source) and have the P to P as secondary. This is because the carrier is a much better clock source than your other KSU is. As far as the Master and Slave that is the way it is with the SL1 protocol one Switch is the Master and the other one slave. Hope we've helped some and good luck.

 

[PhaseJitter]

Thanks again for the info.

Our north office is replacing 28 public copper trunks with a PRI. The DTI has been installed and enabled. We've selected this DTI's clock source as: "Timing Master".

The network access point in this office is a "Pair Gain" Is this a T1 CSU? I've come across references to a T1 CSU and a Clear Channel CSU. I'd assumed that the Norstar's internal CSU was the Clear Channel CSU and the "Pair Gain" was the T1 CSU.

Will speak to provider about upgrade.

Thanks,
Charles

 

[aragon]

Central office should be already master.
Norstar PSTN DTI should be primary
Norstar SL1 DTI should be secondary
Duplicate on both sites if pairgain exists.

David Brillert

http://www.williamsglobal.com

 

[PhaseJitter]

Thanks Aragon and Hawks,

Disabled the internal CSU in South Norstar and also configured PSTN-connected DTI in North Norstar to be Primary and Private network DTI in North to be Secondary as suggested. We haven't had a problem since (6 days); which is longer than we've ever gone before without a network issue. Thanks for all your suggestions.

Charles