Fast switching requires that each L2 frame be sent from the host, through the L2 switch, and then inbound on the routers' interface (where it then gets switched to the outbound interface - usually another VLAN in the same L2 switch). Every frame is sent to the router, rewritten, and then forwarded. L3 switching allows the switch to do the work. The router (usually a RSM blade in a Catalyst) and switch to communicate as a team (MLS). The first frame is sent to the switch, then the router/RSM (where it gets routed to another local VLAN), and then out the switch to the destination. Each subsequent frame is L3 switched by the switch from it's MLS cache (going directly from the source's switch port to the destination's switch port, with the frame being rewritten as if it had been processed by the router), bypassing the router altogether. Hence L3 switching is much faster (wire-speed). Hope this helps. CK Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13948&t=13941 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
