Interface Cacheing

[mjgoodman]

I have a question on the benefits of interface cacheing.

I have 2 6509's that are connected via GIG Ethertrunk. I also have a 7140 connected to each 6509. The VLAN interface number is the same on both switches but have different IP addresses (in case one fails it has an actual address to use as a route).

This configuration works for load balancing the traffic but I want to optimize the routing on the VLAN interfaces. What's the difference or advantage to just using IP ROUTE-CACHE, IP ROUTE-CACHE SAME-INTERFACE, or using none of them at all? Also, would it benefit me to use any of these commands on the other VLAN interfaces which have servers on them?

[smahbub]

If you enable fast or autonomous switching on an interface, packets coming from any other interface on the router are fast-switched (or autonomous-switched) to that interface. If you enable same-interface fast or autonomous switching, packets whose source and destination address are the same are fast or autonomous switched.

You might use same-interface fast or autonomous switching in cases where you have Frame Relay or Asynchronous Transfer Mode (ATM) WAN links configured as subinterfaces on the same main interface. Another situation is when you are using secondary networks on LAN interfaces, as during IP address migration. To enable same-interface fast switching, use the ip route-cache same-interface configuration command.

For the command refer:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_command_summary_chapter09186a00800eeb26.html#xtocid8