Hardware Acceleration
Catalyst 6500 series switches and Cisco 7600 series routers provide WCCP Layer 2 Policy Feature Card (PFC)
redirection hardware acceleration. Hardware acceleration allows Cisco Content Engines to perform a L2 MAC
address rewrite redirection method when directly connected to a compatible switch or router.
Redirection processing is accelerated in the switching or routing hardware, which is more efficient than L3
redirection with Generic Routing Encapsulation (GRE). L2 redirection takes place on the switch or router,
and is not visible to the Multilayer Switch Feature Card (MSFC). The WCCP L2 PFC redirection feature
requires no configuration on the MSFC. The show ip wccp {service-number | web-cache} detail command
displays which redirection method is in use for each content engine.
In order for the router or switch to make complete use of hardware redirection, the content engine must be
configured with L2 redirection and mask assignment.
Use the ip wccp web-cache accelerated command on hardware-based platforms to enforce the use of L2
redirection and mask assignment. Using this command configures the router to form a service group and
redirect packets with an appliance only if the appliance is configured for L2 and mask assignment.
The following guidelines apply to WCCP Layer 2 PFC redirection:
•
The WCCP Layer 2 PFC redirection feature sets the IP flow mask to full-flow mode.
•
You can configure the Cisco Cache Engine software Release 2.2 or later releases to use the WCCP Layer
2 PFC redirection feature.
•
L2 redirection takes place on the PFC and is not visible to the MSFC. The show ip wccp {service-number
| web-cache} detail command on the MSFC displays statistics for only the first packet of an L2 redirected
flow, which provides an indication of how many flows, rather than packets, are using L2 redirection.
You can view information about L2 redirected flows by entering the show platform flow ip command.
The PFC3 provides hardware acceleration for GRE. If you use WCCP Layer 3 redirection with GRE,
there is hardware support for encapsulation, but the PFC3 does not provide hardware support for
decapsulation of WCCP GRE traffic.
IP Application Services Configuration Guide, Cisco IOS XE Release 3S (Cisco ASR 1000)
54
Configuring WCCP
Hardware Acceleration
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