OSPF and ISDN backup

Nov 10, 2008 3 Replies
OSPF and ISDN backup open original image

Hi Guys,



We have a network that uses ospf. We have two central sites that our site routers dial in thru ISDN for backup. I was wondering how many of you are running ospf over isdn (used as backup). How would I go about setting up ospf to run over isdn to work well. We are currently using floating static routes and use RIP ver 2 to redistrubute back to ospf when the rip routes show up (when primary circuit is down). I was wondering if there is a way to set this up using ospf instead of RIP. a while back we were using EIGRP and things were working great, ( isdn would kick in and routes would be there instantly, possibly becuase of EIGRP sucessor and feasable sucessor deal) but due to the carrier we were forced into OSPF.



Let me know if you guys have any ideas or config expamples or web pages that would address my issue.



Big thank you for all that respond.



Thanks,


What does ISDN has to do with with? Once ISDN is up I think of it as piece of wire or a Circuit. Any protocol should be flow throught it. Can you ping across it?

What difference does it make what protocol the carrier is using? Our WAN is MPLS and they only support BGP, but we still use EIGRP as our routing protocol (we redistribute between EIGRP and BGP when talking to the carriers), and we still use EIGRP for our ISDN backup.

I have never done this however I seem to recall a couple of things.

I am sure there are documents "OSPF over demand circuits". There you go -

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Would just making the OSPF traffic un-"interesting" to the dialer work - on top of your floating static routes? i.e. exclude OSPF from the dialer list. Cant think why not - but I could well be wrong.

To Pat - "What does ISDN has to do with with?" Well the usual plan is for the dialer to go down sometime:)

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