Specifications

CHAPTER 4
InterVLAN Routing
To verify your configuration, use the commands show ip interface brief, show interface, or show running-config inter-
face int-#.
Understanding Switch Forwarding Architectures
Packets entering a router or multilayer switch are handled by one of three types of switching:
n Process Switching: Each packet must be examined by the CPU and handled in software. Slowest method, used in
routers only.
n Fast Switching: CPU process switches the first packet in each flow, then caches that information, and switches
subsequent packets in hardware. Faster than process switching, used in routers and multilayer switches. Also called
route caching.
n Cisco Express Forwarding (CEF): A table is prebuilt with adjacency information for all destinations in the routing
table. Fastest method, is the default for Cisco routers and multilayer switches. Also called topology-based switching.
CEF Switching
Multilayer Switching (MLS) is a switch feature that enables the switch to route traffic between VLANs and routed inter-
faces in a highly optimized and efficient manner. Cisco Express Forwarding (CEF) is used to facilitate MLS (see Figure
4-1). Cisco Express Forwarding (CEF) does the following:
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CCNP SWITCH 642-813 Quick Reference by Denise Donohue