[c-nsp] Virtual IP Question

[David Coulson]

Usually when IP takeover occurs, the new 'active' node will send out an 
ARP update message to force all devices on the broadcast domain to 
update their ARP table. I've run this type of failover (as opposed to a 
'virtual MAC') with good success in a variety of configurations. 
Especially if you are only routing to this environment, having fast ARP 
timeouts can often clear out any split brain problems pretty quickly.

What are the symptoms you see when the problems occur? Incorrect ARP 
entry in the switches (I assume these handle VLAN routing too?), bad 
entry in the CAM table, or something else?

Your problem implementing something at the network layer may be that the 
virtual IP will not be available on both nodes, so if you try to 
override the failover functionality, it may not behave as expected.

Paul Stewart wrote:
> Each server is connected to a 6509 switch, on the same VLAN and IP subnet.
> The problem is that the virtual IP representing what people connect to is
> taking over the MAC address of the Ethernet card versus having it's own MAC
> that stays consistent from server to server (as HSRP does with it's active
> IP - MAC never changes for that IP). 
>