Understanding Wccpv2 Configuration - Cisco 6500 Series Software Configuration Manual

Understanding WCCP
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Understanding WCCPv2 Configuration

Multiple routers can use WCCPv2 to service a cache cluster. This is in contrast to WCCPv1 in which
only one router could redirect content requests to a cluster.
using multiple routers.
Figure 35-2 Cisco Cache Engine Network Configuration Using WCCP v2
The subset of cache engines within a cluster and routers connected to the cluster that are running the
same service is known as a service group. Available services include TCP and User Datagram Protocol
(UDP) redirection.
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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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.
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.
Once a stable view has been established, one cache engine is elected as the lead cache engine. (The
lead is defined as the cache engine seen by all the cache engines in the cluster with the lowest IP
address). This lead cache engine uses WCCP to indicate to the control router how IP packet
redirection should be performed. Specifically, the lead cache engine designates how redirected
traffic should be distributed across the cache engines in the cluster.
Clients
Clients
Clients
Clients
Clients
Clients
Chapter 35 Configuring Web Cache Services Using WCCP
Figure 35-2
Internet
Service group
100BASE-T
100BASE-T
100BASE-T
100BASE-T
100BASE-T
100BASE-T
illustrates a sample configuration
Cache 1
Cache 2
Cache 3
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