The original question was the difference between fast switching and L3 switching. The term "L3 switching" gets used in a variety of ways, but using the definition described by CK, think of L3 switching as the next-generation of fast-switching. Historically, that would be an accurate description of development at Cisco. Conceptually L3 switching and fast switching are similar. The new MLS RSM L3 technology was developed by Cisco based on technology already in use for fast switching. Fast switching happens in the router. With MLS, the switching job is distributed and the RSM takes over some of the work. Priscilla At 10:54 AM 7/27/01, C King wrote: >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 ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13984&t=13984 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
