To offset the load of edge router in http request. A http request sent by a host is redirected to local content cache engine (aka content engine), content engine will then send the content back to the requesting host.
Other things about WCCP
1. Only works with IPv4.
2. Has two versions.
3. WCCP version 1 – There can only be one router within a content engine cluster. A content engine cluster can contain up to 32 content engines. Supports http redirection only.
4. WCCP version 2 – Allows multiple routers to be attached to a content engine cluster. That is up to 32 content engines within a cluster, and up to 32 routers in a cluster. In other words multiple routers can participate in traffic redirection to content engines and hence offload the stress from a single router within one cluster.
Apart from supporting http, it supports other service ports in udp or tcp. Hence version 2 is more granular and flexible as compared to version 1.
WCCPv2 also supports MD5 password hashing.
5. WCCP uses udp 2048.
Enable WCCP globally
Router(config)#ip wccp version 2 Router(config)#ip access-list standard ce1 Router(config-std-nacl)#permit host 192.168.0.1 Router(config-std-nacl)#permit host 172.31.1.1 Router(config-std-nacl)#permit host 172.31.2.1 Router(config-std-nacl)#exit Router(config)#ip access-list extended service-types Router(config-ext-nacl)#permit tcp any any eq 80 Router(config-ext-nacl)#permit tcp any any eq 21 Router(config-ext-nacl)#permit tcp any any eq 8080 Router(config-ext-nacl)#exit Router(config)#ip wccp web-cache group-list ce1 redirect-list service-types Router(config)#
In this configuration, there are three content engines in the cluster which support ftp caching, proxy webserver caching and webserver caching traffic redirection. WCCPv2 is the default, hence user does not need to explicitly define version 2. Any service request that is within the redirection list will be redirected to the cache engine by the router.