Web Cache Communication Protocol (WCCP) is a Cisco-developed content-routing protocol that provides a mechanism to redirect traffic flows in real-time. It has built-in load balancing, scaling, fault tolerance, and service-assurance (failsafe) mechanisms. Cisco IOS Release 12.1 and later releases allow the use of either Version 1 (WCCPv1) or Version 2 (WCCPv2) of the protocol.
WCCP allows utilization of Cisco Cache Engines (or other caches running WCCP) to localize web traffic patterns in the network, enabling content requests to be ulfilled locally. Traffic localization reduces transmission costs and download time.
In a layman way we can say Web Cache Communication Protocol (WCCP) is a protocol which is designed and developed to transparently redirect users to cache server, without them having to configure proxy settings in their browsers.
It is used between:
WCCP gives an edge on optimizing resource utilization, and lower response times, when user makes a web request. The response time decreases because "Content Engine"provides the cached information.
How WCCP works?
Let's see how WCCP works with an example:
Request made by web browser,goes to router.
Request is intercepted by router.
Request is redirected to Content Engine using generic routing encapsulation (GRE) frame so that no changes could be made in original packet during transit.
Content Engine can respond to the request as the real server or can forward it to world wide content servers.
WCCP benefits by transparently routing traffic to Content Engine, so you don't have to configure a proxy server. Benefits of Web caching appliances:
Lower response times for Web requests.
Bandwidth utilization is optimized.
Logs of web request are created.
Can easily filter requested content.
With the help of WCCP, "cache cluster" can be used for load balancing, scaling, and fault tolerance along with use of Hot Standby Router Protocol (HSRP) to provide redundancy for WCCP routers.
WCCP V2.0 enhancements
WCCP V2.0 supports the following enhancements to the WCCP V1.0 protocol.
Multi-Router Support:. WCCP V2.0 allows a farm of web-caches to be attached to more than one router.
Multicast Support: WCCP V2.0 supports multicasting of protocol messages between web-caches and routers.
Improved Security: WCCP V2.0 provides optional authentication of protocol packets received by web-caches and routers.
Support for redirection of non-HTTP traffic: WCCP V2.0 supports the redirection of traffic other than HTTP traffic through the concept of Service Groups.
Packet return: WCCP V2.0 allows a web-cache to decline to service a redirected packet and to return it to a router to be forwarded. The method by which packets are returned to a router is negotiable.