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New Member

HSRP Clearification

I'm going to present a scenerio that I understand as correct, someone please tell me if I'm correct/incorrect.

4506:

Vlan10

ip address 10.10.10.2 255.255.255.0

standby 10 ip 10.10.10.1

standby 10 preempt

standby 10 priority 110

Vlan20

ip address 10.10.20.2 255.255.255.0

standby 20 ip 10.10.20.1

standby 20 preempt

standby 20 priority 110

3500:

Vlan10

ip address 10.10.10.3 255.255.255.0

standby 10 ip 10.10.10.1

standby 10 preempt

standby 10 priority 105

Vlan20

ip address 10.10.20.3 255.255.255.0

standby 20 ip 10.10.20.1

standby 20 preempt

standby 20 priority 105

Now, any Vlan traffic that is send by any clients on Vlan's 10 and 20 should be directed (routed) by the 4500. But if the 4500 should go down or some other reason so that the priority goes down by 10, the 3500 will automatically start the routing, correct?

3 REPLIES
Silver

Re: HSRP Clearification

In this configuration traffic is routed by the router with the hightest priority; Catalyst 4506.

You're assumption that the priority on either router could be decreased is wrong. If for instance the network beyond the redundant gateway goes down traffic will be dropped at the active router.

Consider using interface tracking. You can consult documents on Cisco.com.

http://www.cisco.com/warp/public/619/hsrpguidetoc.html

HTH

New Member

Re: HSRP Clearification

Uh oh. Well this isn't good then.

So I would have to add in the line:

standby 10 track vlan10

standby 20 track vlan20

to each of the Vlan interfaces on each switch?

Would this allow the 3500 to assume highest priority and start routing for the Vlans if I (for example) did "int vlan 10" "shutdown" "int vlan 20" "shutdown" on the 4500?

Silver

Re: HSRP Clearification

No you should not track the vlan's, but the next-hop router beyond the redundant gateway.

Let's use a scenario when you have muliple networks. Router A connects to New York router on a point-to-point link. Router B also connects to the New York router on a point-to-point link. When the link to New York on router A fails, router A is still the active gateway, for vlanx and vlany but however unable to forward traffic to New York.

So it is a good practice to track interface POS2/0.1 for instance to check if the router is able to reach the remote network(s).

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