Analysis of Cisco WCCP protocol

Before starting this article, we need to understand what is WCCP, simply put, WCCP (WEB Cache Communication Protocol) cisco is a protocol used to synchronize its edge routers with Content Engines (Cache servers. The Content Engine is responsible for collecting frequently accessed data, such as HTTP. When the master machine accesses the same data, it does not need to access the WAN, you can directly provide content to the Content Engine. Note that WCCP is different from the WEB proxy in the general sense. When WCCP is used, the host does not know that the content engine is involved.
WCCP working mode: www.2cto.com 1) the client sends an HTTP Get request to the external Web server; 2) the router WCCP detects the HTTP Get request and redirects its IP packet to the content engine; 3) the content engine checks whether any requested object exists in the cached content. 4A) if the object is cached, the Content Engine directly sends an HTTP Response to the client. 4B) if the object is not cached, the content engine sends the original HTTP Get request to the external server. 5) If 4B is adopted, the external server sends a response to the client, but does not know that its IP package has been switched to the Content Engine. WCCP uses the UDP Service and the port number is 2048. The vro and Content Engine (or Content Engine pool) communicate with each other through WCCP. With WCCPv1, a single router can interact with up to 32 Content Engines. If there are multiple Content Engines, select the one with the smallest IP address as the main engine. WCCP also supports communication between a set of content engines. The content engine can request a member column table from the WCCP router so that the main engine can decide how to distribute traffic in the cluster. In WCCPv1, only one vro is allowed to participate in the work, while WCCPv2 allows multiple vrouters and multiple Content Engines to form a WCCP service group, which can further expand the system performance. In addition, WCCPv2 not only supports HTTP, but also supports multiple other traffic types. Compared with WCCPv1, WCCPv1 has the following advantages: 1) It supports HTTP (port 80), FTP, FTP Proxy, Real Audio, video, telephony, and other traffic types; 2) supports cache cluster for specific protocol or protocol set segment cache service, A priority system can be used to determine which cluster to use for a cache Protocol; 3) support multicast; 4) support multiple routers (up to 32 in a cluster) for redundant backup and load balancing. 5) The ip wccp password command provides MD5 Security Authentication for WCCP communication. 6) supports Server Load balancer 7) supports transparent error handling. When WCCP is activated globally, WCCPv2. a router can also participate in multiple service groups. In this case, WCCP is set based on ports. The configuration of www.2cto.com WCCP is completed in the Content Engine due to a large part of WCCP configuration. The configuration of the router is not much, as shown in the following code: # conf t (config) # ip wccp web-cache group-address 239.128.1.100 password cisco [nextpage] (config) # int fa 0/0 (config-if) # ip wccp web-cache redirect out (config-if) # int fa 0/1 (config-if) # ip wccp rediret exclude in uses the ip wccp web-cache redirect-list access-list Global Command, WCCP can use the access control list to filter traffic for specific clients. Similarly, using the Global Command ip wccp web-cache group-list access-list, WCCP can apply ACL to determine the type of traffic that the router receives from the content engine. This article is from the fat shark network.