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New Member

HSRP on Interfaces

Is it possible to configure HSRP to run across two interfaces on a 3620.

Basically if my serial line drops I want my ISDN to kick in quick.

Or is there a better solution


New Member

Re: HSRP on Interfaces

I don't think you can use HSRP since you're using a single router . It sounds like what you want is a routing protocol such as RIP, OSPF or EIGRP which will route traffic over the ISDN line when then the serial interface drops.

If your ISDN is not always active it will need to be brought up which of course takes time. Hope this helps answer your question, maybe someone else with more experince might add some insight as well.

New Member

Re: HSRP on Interfaces

That is correct. HSRP will not work in this situation. You would want to use DDR and then some sort of backup configuration such as Demand-Circuit, Snapshot Routing or just a basic Backup Interface.

It would be worth your will to read the post under Remote Access entitled "isdn backup problem"

New Member

Re: HSRP on Interfaces

Thanks your help, I read the article but it confused me a little.

Is it possible for you to give me an example of a config or an idea of a config that would carry out the failover that I need to happen.

New Member

Re: HSRP on Interfaces

The config would be much like the following.

nterface Serial0/0

backup delay 5 10

backup interface Bri0/0

ip address

ip router isis

encapsulation frame-relay

no fair-queue

frame-relay map ip 306 broadcast

no frame-relay inverse-arp

frame-relay lmi-type ansi


interface BRI0/0

ip address

encapsulation ppp

dialer map ip name R6 broadcast 4082222221

dialer map ip name R6 broadcast 4082222222

dialer-group 1

isdn switch-type basic-net3

ppp authentication chap


ip route x.x.x.x y.y.y.y

ip route x.x.x.x y.y.y.y 150


dialer-list 1 protocol ip permit

This would cause the Bri interface to come up 5 seconds after the Serial, FR , links goes down. And the routes that you have through the FR link will leave the routing table and the floating statics over the ISDN will come in. Once the FR link comes back and is up for 10 seconds, the ISDN will come down.

New Member

Re: HSRP on Interfaces

We use to configure HSRP on our ethernet ports running EIGRP on the router with 2 ip routes going to the tier II routers. If one route went down the other route would pass the traffic within milliseconds. Sorry can't be more help...its been awhile.