Outbound Calls receive Fast Busy. H323 Gateway w/ ISDN PRI

[Patrick Sharp]

Hi everyone, I'm running into an issue with outbound calls that is stumping me big time. Last week we had a couple of building power outages that outlasted our UPS so our network devices powered off and on ungracefully. This event fried our two 3845 voice gateways and I cannot get them to boot properly. They were configured as MGCP gateways with T1 controllers configured for ISDN PRI with a CUCM ver 11.5. Luckily I had a newer 3945 router hanging in the rack I was planning to upgrade too so I configured it as a H323 gateway with T1 cards for ISDN PRI and moved the circuits to the new router. The router is receiving inbound calls from PSTN successfully with no reported problems. However, outbound calls to this router are receiving fast busy signals after about 5-6 second dead air delay.  

My provider is reporting they are seeing no activity on their end when the outbound calls are being made. I've been running debugs to try to figure the exact point of failure but haven't been able to pinpoint it exactly. I have noticed when running debug isdn q931, the only call information I see are the incoming calls from the PSTN and no information appears from the outbound calls. Debugging the dial peers do show that the calls are hitting and being matched. I am getting information from the debug voip ccapi inout command but I'm not sure what information to use that can be helpful. I'm attaching the running-config as well as the relevant portion of the output of the debug voip ccapi inout command. 

Any suggestions on where to go from here would be appreciated!

[bichacko · Accepted solution]

Hi,

It looks like your call is being looped back to CUCM using dial-peer 1000:

6888262: Nov 21 12:35:36.412: //-1/80A0935D0300/CCAPI/cc_api_call_setup_ind_common:
Interface=0x1655E3FC, Call Info(
Calling Number=2156759111,(Calling Name=)(TON=Unknown, NPI=Unknown, Screening=User, Passed, Presentation=Allowed),
Called Number=2157839549(TON=Unknown, NPI=Unknown),
Calling Translated=FALSE, Subscriber Type Str=Unknown, FinalDestinationFlag=TRUE,
Incoming Dial-peer=1000, Progress Indication=NULL(0), Calling IE Present=TRUE, ------------------------
Source Trkgrp Route Label=, Target Trkgrp Route Label=, CLID Transparent=FALSE), Call Id=43005


6888283: Nov 21 12:35:36.412: //43005/80A0935D0300/CCAPI/ccIFCallSetupRequestPrivate:
Interface=0x1655E3FC, Interface Type=1, Destination=, Mode=0x0,
Call Params(Calling Number=2156759111,(Calling Name=)(TON=Unknown, NPI=Unknown, Screening=User, Passed, Presentation=Allowed),
Called Number=2157839549(TON=Unknown, NPI=Unknown), Calling Translated=FALSE,
Subscriber Type Str=Unknown, FinalDestinationFlag=TRUE, Outgoing Dial-peer=1000, Call Count On=FALSE, ---------------
Source Trkgrp Route Label=, Target Trkgrp Route Label=, tg_label_flag=0, Application Call Id=)


When I look at the called number: ' dest=2157839549' (this is what is being received on the gateway from CUCM), there are no 'POTS' dial-peer created for it.
Thus, the reason your call loops back to CUCM (delay for a few seconds before busy) and does not go out to the provider.

You can test it out by creating an exact match dial-peer and see if your call goes through.

[Patrick Sharp]

Hi Bichacko, that worked. Thanks for your help!