Configuring ISDN Backup

Unanswered Question
Feb 2nd, 2007


I have a strange situation that I am hoping someone can shed some light on

I am putting a WAN in place for 50 sites in the UK where all the branch locations have a ADSL Tail into an MPLS Cloud and a ISDN 2 backup that dials into the HQ.

The HQ has 2 x 2811 routers, 1 that deals with the MPLS connection (34 Mbps) for primary access and one that houses 2 x ISDN30e's so that the sites can dial into incase the primary link goes down.

The 2811 that is housing the 2 x ISDN30e's at the HQ does not have any PVDM's as its data only, and is not doing any voice but seems to only accept a configuration of PRI Group rather than channel Groups? and thus requires some PVDM's?

Can anybody shed any light on this, I am sure I do not need any PVDM's for data only ISDN trafic.

A configuration guide would be great, but i cant seem to find one thanks

I have this problem too.
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Overall Rating: 3 (3 ratings)
m-haddad Fri, 02/02/2007 - 10:53

Can you please paste the PRI configuration and show controller "interface" as well.


nathan.deane Fri, 02/02/2007 - 12:09

I have not got the configuration to hand at present, however I think it may be a hardware interface issue

I have got a


where I think I need a


would this make sense in the absense of configuration ?

or can a VWIC2-2MFT-T1/E1 be used to recieve multiple ISDN dial in sessions from remote branches ?

m-haddad Fri, 02/02/2007 - 12:29

I guess you have to specify the interface type. The command is card-type in the priviledge mode. E.G "card type e1 1"

Let me know if this solves the problem,


m-haddad Fri, 02/02/2007 - 12:33

Another note these cards support both data and voice applications. Below you can find the link which has configuration examples:

As I mentioned you need to specify the card type before you are able to start the interface configuration.

Hope this solves your issue,

Appreciate your rating,


nathan.deane Fri, 02/02/2007 - 12:37

Thanks for your help and attention so far, rating has been given.

However do you know if the MFT cards can perform as an interface to receive multiple incoming ISDN sessions? or do I need the channelised NM-2CE1T1-PRI ?


nathan.deane Fri, 02/02/2007 - 12:58

thanks for locating that guide, i will give it a go on monday however they only mention AS5200/AS5300 and 7500, where i am using a 2811..hmmmm

m-haddad Fri, 02/02/2007 - 13:04

This guide is for all but there are some settings which are platform specific for AS5200/AS5300. So if you don't have these routers you don't have to perform these configuration tasks.

Let me know how it goes on Monday with you,


mmoszynski Wed, 02/14/2007 - 06:55

Hi Nathan,

So did you manage to configure your 2811 and VWIC2-1MFT-E1/T1 to act as an ISDN PRI hub for Data backup from remote sites?

I want to do the same but find either unclear or contradictory information on Cisco pages...

Are PVDMs necessary?

Or is the NM-PRI card the only one able to perform this function?

If successful, could you please post an extract of your router configuration related to the card?


nathan.deane Wed, 02/14/2007 - 07:09


I have not completed the configuration, but I now know that the VWIC cannot be used for terminating channelised PRI data connections at a hub location.

I have changed this out for a NM-2CE1T1-PRI.

I do not have the configuration as yet, but will share once i do.

m-haddad Thu, 02/15/2007 - 08:52


I am sorry to know that VWIC do not support the scenario you want. I would appreciate if you keep me posted with the new config and progress.



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