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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 33 Configuring Web Cache Services By Using WCCP
Understanding WCCP
Understanding WCCP
The WCCP and Cisco cache engines (or other caches running WCCP) localize web-traffic patterns in
the network, enabling content requests to be fulfilled locally.
WCCP enables supported Cisco routers and switches to transparently redirect content requests. With
transparent redirection, users do not have to configure their browsers to use a web proxy. Instead, they
can use the target URL to request content, and their requests are automatically redirected to a cache
engine. The word transparent means that the end user does not know that a requested file (such as a web
page) came from the cache engine instead of from the originally specified server.
When a cache engine receives a request, it attempts to service it from its own local cache. If the requested
information is not present, the cache engine sends a separate request to the end server to retrieve the
requested information. After receiving the requested information, the cache engine forwards it to the
requesting client and also caches it to fulfill future requests.
This software release supports only WCCP version 2 (WCCPv2). Only a subset of WCCPv2 features are
supported. For more information, see the
“Unsupported WCCPv2 Features” section on page 33-4
With WCCPv2, multiple routers or switches can service the cache-engine cluster (a series of cache
engines); however, in this release, only one Catalyst 3550 switch can service the cluster, as shown
. Content is not duplicated on the cache engines.
Figure 33-1 Cisco Cache Engine and WCCPv2 Network Configuration
Si
Catalyst 3550 switch
with enhanced multilayer
software image
Cache 1
Cache 2
Cache 3
Web
clients
100BASE-T
74627
Internet