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Cisco HSRP question?

Have a question about cisco’s HSRP. My environment currently has 2 Cisco 3845’s. One of them is a cold stanby for the other…to use it if the primary failed we’d have to change the IP and physically move over a Serial DS3 cable and go from there. The network…she is flat. No vlans no internal subnets. All one big ugly layer 2 storm at this point.

I’m thinking about vlanning the network. Basically, we have 3 floors. I was going to put each floor in a different vlan on a different subnet and then one other vlan for the servers and use the routers to route between them. At that point redundancy becomes a must. So I am thinking of implementing HSRP and using it. However, there is no routing protocol in use on the network. Any routes put in are static. Simply because there really are no other upstream or downstream routers (smaller company) routers. So question:
A. Does HSRP mirror config from primary to secondary from each router involved or do I need to make sure that the configs are the same statically? It appears as tho it does not as you simply add the standby address to the interfaces on both routers? Anyway just curuious not the end of the world.
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ics/cs009.htm

B. What about the DS3? I mean right now if it goes down we loose connectivity to a remote site (it’s a serial connection to the primary router). How do I connect that serial side to the other router as well so in the case that the primary goes down the secondary picks up? I’m thinking at this point that this isn’t possible. Being the DS-3 is serial I cant just split the cable and connect it to both routers and expect anything to work. Will this continue to be a manual switch if it goes down?

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Sorenson

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stamperb

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OK that is awesome. Just a few more questions arise with this. The GLBP seems to fit my needs perfectly. I'm still a little hazy on the DS-3 config tho. Right now both 3845's have a NM-1 T3/E3. I'm in a taller building so the cable from the router connects to a Fiber Driver that takes this back down to the entry point to the building. How do I "Split" this coacable so I can have both routers hooked up. Using the track command to make sure only one interface is up at a time makes since. But do they make a splitter for the ds-3 coax cable thing? <-sounds technical i know :-)

stamperb

ASKER

Also it would appear that the standby track and standby preempt are featuers of HRSP so are you suggesting I use both GLBP and HSRP together? And if so are you meaning GLBP on the Ethernet interfaces and HRSP on the DS-3 interfaces

stamperb

ASKER

Ignore that last question I see the track command available with GLBP as well.

stamperb

ASKER

Same goes for a T1...i mean it comes in serial...how would you hook it up to both routers so that it could pick up on the other? Do they make "splitter" cables for such a thing?

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mikebernhardt

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stamperb

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Thats great. Last part then. Can I use this for just the Ethernet interfaces (routing the vlans) to provide the availability there and not on the serial interfaces? Is it all or nothing or interface specific? I presume looking at the commands that its interface specific?

mikebernhardt

It's interface specific. So even if you can't currently provide failover for your exit (the DS-3), at least you can provide high availability for your LANs.