PRI issue with channels in MBSY state - Meridian Opt 11 and Cisco Voice Gateway (E1)

[nmcmo]

Hello everyone,
I've been a long time reader / user of this forum and it has been extremely valuable to me since I have maintained our company Nortel Meridian Opt 11

For a couple of years not we have had integration with our Cisco Unified Collaboration platform and the 2 systems are linked like this:

Cisco Call Manger --> Cisco Voice Gateway router with E1 rj45 interface <----> PRI card (NTBK50AA PRI card with Clock Card NTAK20BD and Daughterboard NTBK51AA) --> DASS2 ISDN 30

All of this has been working flawlessly until the other day when we had some power issues and the Cisco voice gateway was rebooted. Sometimes if this happens I need to reset the PRI loop and d-channel following this procedure:

https://pbxbook.com/meridian/maint/e1_pri.html

But yesterday this has not worked and we cannot make calls between the Cisco UC endpoints and the phones connected to the Nortel Meridian.

The channels seem to go into a MBSY state:


DTI000
SL-1 --- SYS-12/AXE-10 SWE/NUMERIS/SWISS/TCNZ
/EUROISDN/SING/THAI/MSIA/INDO/CHNA
/INDI/PHLP
CHANNEL TIMESLOT MAPPING

.
SL-1 NETWORK TIMESLOT
B-CHANNEL 1 -15 1 -15 1 -15
16-30 17-31 17-31
D-CHANNEL 31 16 16
stat 2

PRI2 LOOP 2 - ENBL
REF CLK: DSBL
SERVICE RESTORE: YES
ALARM STATUS: MAINT
CH 01 - MBSY TIE VOD * CH 02 - MBSY TIE VOD *
CH 03 - MBSY TIE VOD * CH 04 - MBSY TIE VOD *
CH 05 - MBSY TIE VOD * CH 06 - MBSY TIE VOD *
CH 07 - MBSY TIE VOD * CH 08 - MBSY TIE VOD *
CH 09 - MBSY TIE VOD * CH 10 - MBSY TIE VOD *
CH 11 - MBSY TIE VOD * CH 12 - MBSY TIE VOD *
CH 13 - MBSY TIE VOD * CH 14 - MBSY TIE VOD *
CH 15 - MBSY TIE VOD * CH 16 - MBSY TIE VOD *
CH 17 - MBSY TIE VOD * CH 18 - MBSY TIE VOD *
CH 19 - MBSY TIE VOD * CH 20 - MBSY TIE VOD *
CH 21 - MBSY TIE VOD * CH 22 - MBSY TIE VOD *
CH 23 - MBSY TIE VOD * CH 24 - MBSY TIE VOD *
CH 25 - MBSY TIE VOD * CH 26 - MBSY TIE VOD *
CH 27 - MBSY TIE VOD * CH 28 - MBSY TIE VOD *
CH 29 - MBSY TIE VOD * CH 30 - MBSY TIE VOD *
CH 31 - DCH 2

The config / setup on the Cisco side has not changed but I'm not completely ruling that out at this stage. I notice that there are "DTA300 2" messages being repeatedly (every few seconds or so) at the terminal of the Meridian and this has lead me to suspect a clocking issue perhaps?

Does anyone have any advice of what I can try to at least narrow down the problem / issue?

Apologies for my lack of in-depth knowledge of the Meridian. Any help very much appreciated.

Thanks

 

[ramsay]

Where is the clock source coming from?

Ramsay

 

[nmcmo]

Hi Ramsay,

Thanks for your quick reply. Turns out mgcp was 'stuck' at the Cisco Voice Gateway side.
I resolved this with a 'no mgcp' and then a 'mgcp' and the d-channel came up immediately.

I found the final posting in this thread on the Cisco forums very useful for troubleshooting this issue:

https://community.cisco.com/t5/ip-t...-on-quot-tei-assigned-quot-state/td-p/2928002

Just wanted to update this in the hope that others might find it useful in the future.

Thanks all