Information About Wccp; Wccp Overview - Cisco ASR 1000 Series Configuration Manual

Information About WCCP

Catalyst 6500 Series Switches and Cisco 7600 Series Routers Access Control Lists
When WCCP is using the mask assignment, any redirect list is merged with the mask information from the
appliance and the resulting merged ACL is passed down to the Catalyst 6500 series switch or Cisco 7600
series router hardware. Only Permit or Deny ACL entries from the redirect list in which the protocol is IP or
exactly matches the service group protocol are merged with the mask information from the appliance.
The following restrictions apply to the redirect-list ACL:
• The ACL must be an IPv4 simple or extended ACL.
• Only individual source or destination port numbers may be specified; port ranges cannot be specified.
• The only valid matching criteria in addition to individual source or destination port numbers are dscp
• The use of fragments, time-range, or options keywords, or any TCP flags is not permitted.
If the redirect ACL does not meet the restrictions shown, the system will log the following error message:
WCCP-3-BADACE: Service <service group>, invalid access-list entry (seq:<sequence>,
reason:<reason>)
WCCP continues to redirect packets, but the redirection is carried out in software (NetFlow Switching) until
the access list is adjusted.
Information About WCCP

WCCP Overview

WCCP uses Cisco Content Engines (or other content engines running WCCP) to localize web traffic patterns
in the network, enabling content requests to be fulfilled locally. Traffic localization reduces transmission costs
and download time.
WCCP enables routing platforms to transparently redirect content requests. The main benefit of transparent
redirection is that users need not configure their browsers to use a web proxy. Instead, they can use the target
URL to request content, and have their requests automatically redirected to a content engine. The word
"transparent" in this case means that the end user does not know that a requested file (such as a web page)
came from the content engine instead of from the originally specified server.
A content engine receiving a request attempts to service it from its own local cache. If the requested information
is not present, the content engine issues its own request to the originally targeted server to get the required
information. A content engine retrieving the requested information forwards it to the requesting client and
caches it to fulfill future requests, thus maximizing download performance and substantially reducing
transmission costs.
WCCP enables a series of content engines, called a content engine cluster, to provide content to a router or
multiple routers. Network administrators can easily scale their content engines to manage heavy traffic loads
through these clustering capabilities. Cisco clustering technology enables each cluster member to work in
parallel, resulting in linear scalability. Clustering content engines greatly improves the scalability, redundancy,
and availability of your caching solution. You can cluster up to 32 content engines to scale to your desired
capacity.
IP Application Services Configuration Guide, Cisco IOS XE Release 3S (Cisco ASR 1000)
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Configuring WCCP