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Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E
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Chapter 35 Configuring Web Cache Services Using WCCP
Understanding WCCP
• Layer 2 redirection takes place on the PFC and is not visible to the MSFC. The show ip wccp
web-cache detail command on the MSFC displays statistics for only the first packet of a Layer 2
redirected flow, which provides an indication of how many flows, rather than packets, are using
Layer 2 redirection. Entering the show mls entries command displays the other packets in the Layer
2 redirected flows.
Note A future release of Cisco Application and Content Networking System (ACNS) software (Release 4.2.2
or later) supports the accelerated keyword with Release 12.1(13)E and later releases.
Understanding WCCPv1 Configuration
With WCCP-Version 1, only a single router services a cluster. In this scenario, this router is the device
that performs all the IP packet redirection. Figure 35-1 illustrates how this configuration appears.
Figure 35-1 Cisco Cache Engine Network Configuration Using WCCP-Version 1
Content is not duplicated on the cache engines. The benefit of using multiple caches is that you can scale
a caching solution by clustering multiple physical caches to appear as one logical cache.
The following sequence of events details how WCCPv1 configuration works:
1. Each cache engine is configured by the system administrator with the IP address of the control
router. Up to 32 cache engines can connect to a single control router.
2. The cache engines send their IP addresses to the control router using WCCP, indicating their
presence. Routers and cache engines communicate to each other via a control channel; this channel
is based on UDP port 2048.
3. This information is used by the control router to create a cluster view (a list of caches in the cluster).
This view is sent to each cache in the cluster, essentially making all the cache engines aware of each
other. A stable view is established after the membership of the cluster remains the same for a certain
amount of time.
Router
S6529
Internet
100BASE-T
Cache 1
Cache 2
Cache 3
Clients
Clients
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