11-1 Fast Switching

• Fast switching enhances the packet movement between interfaces by creating a high-speed cache entry to be used for switching.

• Fast switching is enabled by default on interfaces capable of fast switching.

• Fast switching can be managed on Cisco routers to control the process.

Configuration

Many of the configurable options for fast switching are enabled by default. The configuration step in this section is optional or varies depending on the hardware.

1. (Optional) Enable fast switching:

    (interface)  ip route-cache  [  same-interface  ] 

   This command enables the fast switching process; this is the default setting for many interfaces. Fast switching should be disabled when it impedes performance, such as when you have multiple paths greater than 64 KB or lower links. The same interface option allows fast switching for packets going back out the same interface they were received on, such as multipoint Frame Relay interfaces.

Example

This example configures fast switching to be performed on the same interface for a Frame Relay multipoint serial interface:

  interface s0.1 point-to-multipoint   ip address 10.1.1.1   ip route-cache same-interface