PRI Slips and Error

[balukr]

We have a customer connecting their Nortel PBX via PRI to a 2851 router with VWIC2-2MFT-T1 on the Cisco CM side.

PRI is up and we are able to make calls bothways but the PRI is flapping (up and down every 10 mts). I checked ("sh controller t1") the router and saw just slip and error seconds go up but Line code and path code violation stays clean with 0 errors.

2851 router is providing clock to PBX here is the config

clock timezone AZ -7

network-clock-participate wic 0

ip subnet-zero

!

!

ip cef

!

!

no ip domain lookup

!

isdn switch-type primary-ni

!

voice-card 0

no dspfarm

!

controller T1 0/0/0

framing esf

clock source internal

linecode b8zs

pri-group timeslots 1-24 service mgcp

!

interface Serial0/0/0:23

no ip address

isdn switch-type primary-ni

isdn protocol-emulate network

isdn incoming-voice voice

isdn bind-l3 ccm-manager

no cdp enable

------------

One thing I couldn't do is one of the clocking command "network-clock-select" if I try it comes back with an error "*** Controller T1 0/0/0 is NOT deriving Clock from Line".This is the only T1 PRI connected on this router and I have no other T1 to point for clocking.

How do I fix this slip error so the T1 won't flap anymore and stays clean.

Thanks for your help.

[paolo bevilacqua]

Hi, the requirement that ties a given switchtype to clock source appears quite strange, anyway, have him do that, in reality all switchtypes are interoperable at least for basic calls.

Another thing you can try, although I'm not convinces, can you try to change "cablelenght" and gain under controller T1.

[balukr]

I already tried both cable length "long" and "short" didn't help.

[paolo bevilacqua]

I've posted a link to this in voice forum and I hope that my friend Rob will be able to help.

[Rob Huffman]

Hi Folks,

There are a few things here that we came across when first setting up our integration between CCM and our Nortel M61c.There are 4 PRI's configured between the two systems. The original config used Cisco 6608 blades but we now use 2x2811 ISR's with T1 VWIC's.

We tested using ESS5,NI2 and D100 (DMS-100).

All three interface protocols were available on the Nortel Meridian (maybe the Nortel Tech has not seen this).

The only one that has ever worked properly was DMS-100! It is a bit of a bear to change this on the Nortel as the whole PRI config has to be removed and re-programmed line by line when switching between IFC Types, so there may be a reluctance to change these. I know from first hand experience that this is not alot of fun, but this is the first thing that I would do. All of the rest of the changes that could be done would be pure speculation until the proper Interface between the two systems is setup.

Here are some great docs (have a close look at the White Paper);

Cisco Unified CallManager

Case Study: Nortel 61C PBX to Cisco IP Telephony Migration

From this good doc;

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_white_paper09186a00801115e0.shtml

Nortel Meridian PBX and Cisco CallManager Integration

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_configuration_example09186a008011888c.shtml

Hope this helps!

Rob

[balukr]

Rob,

Thanks for your prompt reponse and for the doc's. We were planning to try QSIG not only to fix this also it will pass caller id across the tie line.Can we try this or only DMS 100 will work ?

One more question on Nortel side

TKTP has to be configured as TIE or it doesn't matter . Since it is going to be a tie line I just want to make sure this is configured correct on that side.

Thank you so much again for your help.

[Rob Huffman]

Hi Balu,

You are most welcome :) Yes, QSIG will also work. We used DMS100 due to the fact that our Nortel release did not support QSIG.

For your second question, yes, this must be configured as TKTP TIE.

Hope this helps and best of luck!

Rob

[balukr]

Rob,

Sorry for the delayed update I have to work with PBX tech's schedule.We changed the switch type to QSIG today still had the same slip error so we changed to DMS-100 but this time Nortel side D channel was not coming up at all.He said he tried what ever he can on his side to troubleshoot this, since I'm not familiar with Nortel side I can't speak for him.

PBX tech has the same setup works fine with another customer site with QSIG so he is going to download that config and configure the same way here and try this again tomorrow.

If there are any other thoughts let me know if not I'll update tomorrow.

Thanks again for your help.

[balukr]

Finally T1 is up and running clean now.PBX tech changed couple of settings in Nortel side (he got that config from working QSIG tieline and I'll try to get that setting from him if possible and post it ), it is setup as QSIG and we are getting clock from Nortel now because this time we were seeing LCV's and PCV's along with slips when we set clock on Cisco CM side as Master as soon as we changed it to User and added the "network-clock-select" command it is running clean now.

I wish PBX tech was able to make the clock setting on his side as master before so we don't have to go through all this anyways thanks for everyone's help on this.

[paolo bevilacqua]

Good, like some people says, "router is (almost) never wrong". Now all what you've to do is refine the qsig config on the CM and you will be able to do certain sophisticated qsig things like calling name, inter-system transfers and forwards and some more that I don't even know about.

[balukr]

Yeah I saw that too calling name already works ,I may play with other features later.