PRI Dropped Calls

[Mattmayn]

I have a system running MCD 4.2 that is reporting dropped calls on their PRI. I have no logs other than my log in/out and day/night changes each day. DTSTAT for the circuit is clean for the past 24 hours and the provider says everything looks fine on their end (big shocker). Any ideas on this one?

This is how it was reported from the customer:
Periodically, once you have dialed the # you are trying to reach, the phone will go back to a dial tone.
It is not all day, all the time – completely random.

They also claim that when that happens they can not dial out either.

It all points to provider to me but I need something to go to them with if possible.

[ralph]

This ain't gonna be fun....
I've had the same issue before a few times.
One turned out to be a T-3 between the customer and the CO that was dropping
But I've also see it where the carrier was delivering via a Flex (VoIP) circ to the prem and then hands off via PRI from a router.
The PRI will look good with no errors but what you can't see it the T1(s) carrying the VoIP was dropping.
Once I could actually get the carrier to check the T1 to them then they saw the issue.

But like you say, no surprise the carrier doesn't see a problem. 

Ralph

[Mattmayn]

This PRI is being deliveried by Comcast on a cable modem and then it hits a couple of other devices (one being their router) before it is handed to me as a PRI. They are supposed to be in the process of putting this circuit on the fiber they have in the building already that carries the metro-e for this customer and that would eliminate some of the hardware. Not sure why that wasn't done in the first place. I think the cable modem is the problem myself. I had a lower level tech on the phone yesterday and I couldn't convince him that the interface would stay up even if the internet connection was spotty since the PRI links are looking at each other and the modem doesn't care. I guess I will try again.

Looks like a fun day, or longer.

[acejavelin]

Definitely sounds like a carrier issue... I would want to see EDT L2L3 traces of a failed call to see where the issue lies, the command is:

EDT TRACE TSP L2L3 <PLID of PRI>  (Note this is a toggle, issue it once to start the trace, again to stop the trace)

If the system has a fair amount of traffic this can be very lengthy quickly and difficult to diagnose, but it should give you the information you need to see where and possibly why the call is not completing or disconnecting.