RCSP Study Guide - WCCP Redirection
By default, all TCP traffic is redirected, optionally a redirect-list can be defined where only the contents of the redirect-list are redirected. A redirect-list in a WCCP configuration refers to an ACL that is configured on the router to select the traffic that will be redirected.
Traffic is redirected using one of the following schemes:
• GRE (Generic Routing Encapsulation)
Each data packet is encapsulated in a GRE packet with the Steelhead appliance IP address configured as the destination. This scheme is applicable to any network.
• L2 (Layer 2)
Each packet MAC address is rewritten with a Steelhead appliance MAC address. This scheme is possible only if the Steelhead appliance is connected to a router at Layer 2.
The either value uses L2 first—if Layer 2 is not supported, GRE is used. This is the default setting.