a possible security problem. Enabling the WCCP Outbound ACL check feature ensures that redirected packets are subject to any ACL conditions configured on the original egress interface. WCCP Service Groups WCCP is a component of Cisco IOS XE software that redirects traffic with defined characteristics from its original destination to an alternative destination. The typical application of WCCP is to redirect traffic bound for a remote web server to a local web cache to improve response time and optimize network resource usage.
The nature of the selected traffic for redirection is defined by service groups (see figure below) specified on content engines and communicated to switches or routers using WCCP. WCCPv2 supports up to 32 switches per service group. Each service group is established and maintained independently. WCCPv2 uses service groups based on logical redirection services, deployed for intercepting and redirecting traffic. The standard service is web cache, which intercepts TCP port 80 (HTTP) traffic and redirects that traffic to the content engines. This service is referred to as a well-known service , because the characteristics of the web cache service are known by both the switch and content engines.
A description of a well-known service is not required beyond a service identification. To specify the standard web cache service, use the ip wccp command with the web-cache keyword. More than one service can run on a switch at the same time, and switches and content engines can be part of multiple service groups at the same time. Note Figure 2: WCCP Service Groups The dynamic services are defined by the content engines; the content engine instructs the switch which protocol or ports to intercept, and how to distribute the traffic.
The switch itself does not have information on the characteristics of the dynamic service group’s traffic, because this information is provided by the first content engine to join the group. In a dynamic service, up to eight ports can be specified within a single protocol. Configuring WCCP WCCP Service Groups Configuring WCCP 7