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Community Member

D-channel out of Service Error - drops all calls

ladies and gentlemen,

We are having a serious problem with our PRI line, when its plugged into the Catalyst E1 6608 blade, its losing its "D-channel" and dropping calls! We've now upgraded to CM 3.1(2c), we have all the latest firmware on the phones, gateway, it seems that all is working beautifully at night when we are testing, however, in the day when we start getting any sort of load on the system (more than a couple of calls) calls start dropping and we get this error in the log:

Error DchannelO OS- D channel out of service

Reason[Optional]: 0

Explanation D channel has gone out of service

When this happens we have no choice but to interrupt phone service for everyone by putting the PRI line back into the IOS Gateway, and it works fine ..


WS-6006 version 6.2(2)

WS-6608-E1 blade firmware 5.4(2)

ON the 6608 blade:

Port 3/1 Registered as E1 PRI

Port 3/2 Registered MTP

Port 3/3 Registered MTP

Port 3/4 (Port Host Processor Not Online) - This could be the problem! however, we cannot get this port to do anything, i.e. disable, change vlans, nothing - it is

currently in "enabled" state though!

Port 3/5 Registered MTP

Port 3/6 Registered MTP

Port 3/7 Registered MTP

Port 3/8 Registered MTP

The overnight Error logs do not get this message, so i'm pretty sure it has something to do with activity on the line, causing it to lose its signal??

Does anyone have any clue about this? I'm pleading for advice/knowledge regarding this issue ...

thanks in advance! - jason

Community Member

Re: D-channel out of Service Error - drops all calls

Try putting a loop-back plug in the unused port and resetting the module. There is a chance that the constant alarms from the unconnected port are causing a problem.

This is just a guess!


Community Member

Re: D-channel out of Service Error - drops all calls

I had the exact same symptoms with a CAS T-1. Under load it would drop calls. I moved to a VG200 CAS T-1 port and it works fine. Cisco TAC said it was a bug. May be the same thing in your case. They gave me a beta load for the 8 T-1 that fixed it. Call TAC and escalate it to a P2. Somebody should help you right away!

Community Member

Re: D-channel out of Service Error - drops all calls

As I known, Cat.6509 8 port T1 blade can't support CAS-T1 protocol.It's a future. Maybe will be usable next version.PRI is supported.

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