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HSRP with 2 routers 3600

I have a 3620 router with 8 ISDN and one Ethernet port and I want to put a secondary one using HSRP (the second router have 1 PRI and one Ethernet port.

Is it possible to use HSRP on ethernet or is it necessary to use serial ?

What is the best solution ?


Re: HSRP with 2 routers 3600

HSRP is a LAN protocol, so it goes on the Ethernet ports. You can configure HSRP to track interfaces, but generally, that does not work well with dial links, which are always up, frequently even when not functional.

As an aside, be careful using a hunting group to map all your ISDN lines to a single number. Some failure modes will not "busy out" a line and turn it into a black hole for incoming calls. I like to split my dial in into at least two hunting groups and configure the calling routers to call both. That way, a line failure cannot take down all my lines.

I suggest you also spend some time reading about HSRP and what it does (and also what it does not do). There is a lot of good material here on I also cover the topic in Chapter 6 of my book.

Good luck and have fun!

Vincent C Jones

Re: HSRP with 2 routers 3600

You can always configure HSRP on two ethernet-interfaces on the same LAN segment. Normally the routers behind these interfaces also share the same IP destinations. With ISDN you are typically doing static routing and connections can land on either router. It is therefore nescessary to include the -redistribute connected- command under your routing protocol config to make sure that traffic is routed to the correct router.

In this way you can achieve some fault-tolerance on the ethernetside and still have different ISDN connections on either router.