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New Member

SHDSL with ADSL backup using C1700 with dual WIC

Hi All,

I have a Cisco 1700 router with SHDSL and ADSL WICs.

I want to use the SHDSL interface as the primary link to the Internet (with assoicated default route and nat), while having the ADSL interface as the backup in case the SHDSL fails.

The typical configuration I was thinking:

- atm0 (SHDSL) configured to use dialer0

- atm1 (ADSL) configured to use dialer1

- default static with admin 1 to dialer0

- default static with admin 2 to dialer1

The main issue with this approach is that I cannot use the "backup" command to track a virtual-access interface as it is non-configurable. I cannot use the dialer interface either as it is always up and will never go down. The other related point is that the default static to dialer0 will never go down as it is the virtual-access that goes down.

Does anyone know what other approach can be used to track a PPP virtual-access interface to bring up a backup DDR if it fails?



New Member

Re: SHDSL with ADSL backup using C1700 with dual WIC

Soemthing like what you are trying to achieve has also preyed on my mind - up to now i havent needed to implement anything.

The link

might give you some ideas about dial backup - substituting the ISDN bits for your ADSL - but surely - I would hope - the actual theory should be the same to kick in another interface if the main one goes down.

I would be interested in knowing if you get this solved




Re: SHDSL with ADSL backup using C1700 with dual WIC


What you can do in this scenario is enable dialer watch to watch the host route that you install from the upstream PPP peer (ISP) on the primary connection. This way when that primary goes down the router will lose the host route thus enabling dialer watch to use the alternate connection.

Heres a doc sample


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