Our telco is providing 56 t-1 across 2

channelized DS-3s. We terminate the

ds-3's into adtran atlas 800's Then we

map the T-1's out individual t-1 ports.

We connect these individual t-1's to an

8540 with C85MS-8TI-IMA's installed using

t-1 cross-over cables.

The adtran gets it's clocking from the ds-3.

The 8540 ports are clocked as network-derived

and the ima's are set to common clock.

The far end of these connections are also set

to

network derived and common for the ima's.

These connections then leave the 8540 on an

oc-3 to point to point atm interfaces on an

oc-3 card in a 7500 router.

We have a few t-1 connections that are stand

alone connects and not ima'd on the 8540.

These connections interrmittently go down then

come back up. Yet there are no errors registered

on the interface or its subinterfaces in the show interface.

The telco has been kind enough to to provide

hard loops at test points from end to end.

On 3 out of 4 of these no ima's I am able to

ping the local interface ip address and they

past all tests. The fourth shows interface

up but doesnt repond to the pings.

I am hoping my issue here is timing or that

I forgot a command somewhere.

Help!!

Bob