gating the command disables CEF globally: R1 (config)#no ip cef To enable or disable CEF on a single interface, use the interface command ip route- cache cef: R1 (config)#int s0/1 R1 (config-if)# ip route-cache cef Negating the command disables CEF on the interface. CEF will load-balance packets across equal-cost links. By default, load balancing will be done on a per-destination basis. This means every packet for a single destination will use the same link. CEF also allows you to configure load balancing on a per-packet basis. This can be beneficial if, for example, there is only one host on the far end of the links or there is a large server that consumes the majority of the bandwidth for any single link. Certain protocols, such as VoIP, cannot tolerate per-packet load bal- ancing, because packets may arrive out of order. When using such pro- tocols, always ensure that load balancing is performed per destination, or use a higher-level protocol such as Multilink-PPP. To change an interface to load-balance using the per-packet method, use the ip load- sharing per-packet interface command: R1(config-if)#ip load-sharing per-packet To reconfigure an interface for per-destination load balancing, use the ip load-sharing per-destination interface command: 1(config-if)#ip load-sharing per-destination Configuring and Managing Switching Paths To show the CEF tables in an easy-to-read format, use the show ip cef command: R1#sho ip cef Prefix Next Hop Interface 0.0.0.0/32 receive 10.1.1.0/24 attached Loopback1 10.1.1.0/32 receive 10.1.1.1/32 receive 10.1.1.255/32 receive 10.2.2.0/24 attached Loopback2 10.2.2.0/32 receive 10.2.2.2/32 receive 10.2.2.255/32 receive 10.3.3.0/24 192.168.1.2 Serial0/1 10.4.4.0/24 192.168.1.2 Serial0/1 10.5.5.0/24 attached FastEtherneto/1 10.5.5.0/32 receive 10.5.5.1/32 10.5.5.1 FastEtherneto/1 10.5.5.5/32 receive 10.5.5.255/32 receive 10.10.10.0/24 192.168.1.2 Serial0/1 192.168.1.0/24 attached Serial0/1 192.168.1.0/32 receive 192.168.1.1/32 receive 192.168.1.255/32 receive 224.0.0.0/4 224.0.0.0/2