AS5400 & ISDN D-channel operation

Unanswered Question
Feb 13th, 2006
User Badges:

Newby to AS5400, bear with me.

The primary d-channel is out of service and backup is inservice, layer 3 calls are being made, telco says circuit is fine, how can D-channel be down? There are 7 NFAS's...Thanks in advance..

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
subhrojyoti.banerjee Tue, 02/14/2006 - 19:32
User Badges:


Was the primary D channel up and running before? In case the primary is down the backup D channel would remain active. Can you please send me the following information-

1. sh run

2. show isdn status

3. show isdn nfas group

4. sh isdn serv

5. show controller t1



it sounds like you have configured pri-groups with NFAS on your controllers... like this:

controller E1 1/0

pri-group timeslots 1-31 nfas_d primary nfas_int 0 nfas_group 0 service mgcp


In this case the D-Chan from the primary NFAS is automatically reserved for signaling by the IOS.

Sorry but i don't remember the document on CCO.

Might be the answer on your question.



j.mccartn Thu, 02/16/2006 - 09:49
User Badges:

Hi all, thanks for your responses. We are looking at the issue and I believe it may be on the carrier end. Did some checking and looks like when it does come back up we have to force the Primary to take over, since the backup won't relinquish control, correct?


This Discussion