Hi ..please see below from a session of Networkers 2005
"Failover
?Layer three: Pix failover, Cisco IOS HSRP
?Layer two: spanning tree
Typical IPS sensors (non layer three) do not and cannot control network failover; they function like a wire and a failure of the sensor should look like a failure of a wire; the network will respond accordingly; fail-open capabilities help but do not truly solve the problem.Æ
True High Availability Is Something Built into the Network, Never Built into a S