PRI Backhaul CUCM 7.1.5 2921 E1 doens not work ?

Unanswered Question
Aug 27th, 2010

Hi ,

I've a topo including a CUCM runing version 7.1.5 , a Gateway 2921 With a wic  E1/T1 card running IOS 15.1.2T1 , the gateway is configured with MGCP PRI backhaul.

Problem is : sometime my call incoming and outgoing are blocked , sometime ONLY outgoing call are blocked and sometime ONLY incoming call are blocked , NO pb on CSS, partition etc.. , i can see on Backhaul debug the call on Gateway but it's rejected .

have you already seen this pb ?

I have this problem too.
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Felipe Garrido Fri, 08/27/2010 - 06:42

Can you provide additional information on the errors you see in the debugs? If you've collected debugs or CUCM detailed traces, can you post them?


j.faure Mon, 08/30/2010 - 01:20

Hi ,

I can sent it , but you will see nothing as it's a PRI Backhaul

Thanks for your help .


j.faure Mon, 08/30/2010 - 02:59


I've checked on gateway and pb is when the channel 31 is used during incoming call from PSTN to CUCM , i've an error "invalid channel" . I've changed channel allocation order in CUCM gateway parameters to (TOP to DOWN) and pb is solved for the moment , because incoming call are coming on channel 5 and outgoing on chanel 1 .

BUT it's not really clear and surely not very stable so i guess it's a bug MGCP .


Felipe Garrido Mon, 08/30/2010 - 06:17

Can you provide the SDI traces as well for a failed call? Only the SDL traces were attached making it difficult to trace the call.  Can you check the current status of channels within RTMT? Do you see channel 31 in an OOS state? If so, can you check the MGCP service maintenance parameters under "Service Parameter>>Advanced."


j.faure Tue, 08/31/2010 - 01:01

Hi Felipe ,

Thanks , problem has been solved , it was due to TELCO PRI on which the 10 last channel was not configured even if i saw all channel available on isdn service command and RTMT . ( still not clear concerning incoming call but ..)



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