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WCCP is a relatively new protocol that allows routers to talk to your cache server. It isn't a routing protocol in the traditional sense, but it may be directing traffic around your network in the near future. Tom Lancater helps you familiarize yourself with its operation and benefits in this tip.

Historically, proxies have come in two flavors: those that sit in-line and intercept traffic that passes through them, and those that require clients to be configured to use them, like SOCKS proxies. Each has advantages, of course. Configuring clients is annoying and expensive, and should be avoided if possible. Trying to get proxy servers directly in the path of traffic is difficult and kludgey, particularly if there are redundant circuits or alternate paths.

But now, many vendors are starting to support a relatively new protocol that offers perhaps the best of both worlds: the Web Cache Communication Protocol (WCCP), which is sometimes referred to as Web Cache Coordination Protocol and other times as Web Cache Control Protocol. Whatever it stands for, WCCP isn't a routing protocol in the traditional sense, but it may be directing traffic around your network in the future, so you should familiarize yourself with its operation and benefits soon.

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The short story is that it allows a router to talk to your cache server. What they're chatting about is what type of traffic the router should intercept and redirect over a GRE tunnel to the cache. WCCPv2 supports some security measures, like authentication, and supports multiple routers, cache servers and a lot more protocols, so you can do file server and other types of caching -- not just WWW HTTP.

So, if you're thinking you need a cache or proxy, the WCCP model is definitely something you should consider, but because it's a little different, here are some things to think about:

  1. All traffic from clients to PCs doesn't go directly between the cache and the client, but flows several times through the router, which means you may need more muscle. Don't skimp on processing and memory for WCCP-enabled routers. And pay attention to traffic flow so you don't create bottlenecks.
  2. You'll need to prepare your helpdesk or network operations support people to troubleshoot a somewhat more complex environment.
  3. Much like VOIP is causing organizational changes between voice and data IT departments, a lot of new technology like WCCP will be blurring the delineation of responsibilities between the server and application and network support teams. Sort this out before your first outage.

This was last published in December 2005

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