ErEkoSuave

We're dealing with an Option 51 here running software version 2821, release 3 (we're phasing this PBX out at the end of the year, thus the neglect). We have a PRI between this option 51 and a Cisco voice gateway. This PRI is for calling to and from and Cisco UCM system and this option 51. We have two 2-way PRIs coming in from our LEC for access to/from the PSTN. When a call destined for the PSTN is made on the Cisco side, the call is routed through the PRIs on the option 51. When a call comes in from the PSTN destined for a DN on the Cisco side, it hits the PRIs on the Nortel side and then routes through the 51<->Cisco PRI. Confused yet?


High-level flow of a call to a Cisco DN from PSTN:
PSTN->LEC PRI (4 digits)->Option51->CDP DSC->Cisco gateway->Cisco Call Manager->Cisco set with DN

Here's the problem. Some calls from the PSTN make it to a Cisco DN fine, but then some calls don't. The calls that don't make it never ring the Cisco set, they just ring our switchboard operator. As far as we can verify, the calls that don't work all are from long distance callers, meaning it's not a local call for the caller, although we can't verify that these are the only calls affected.

I have checked that there are no IDC entries getting in the way. When I turn on MSGI and MSGO on the Nortel-to-Cisco trunk, I never see an unsuccessful call come across, which says to me that for some reason, the Nortel PBX isn't using, or has some issue with, the CDP entries.

As some of you may know from my other posts, I'm very amateur with these Nortel PBXs. I'm at a loss as to where I should go from here. We're hoping to avoid paying someone to fix this for us, naturally, but may have to regardless. An RDB print out of the Nortel-to-Cisco trunk is below. Any feedback is appreciated.