Web Caching

Location

Where should you place a cache or caches within your network? The answer, of course, depends on your particular network. Most likely, you should locate your cache near your firewall or border router—in other words, near the last piece of equipment that you manage as packets from your network head out to the Internet. This maximizes the number of people who can use the cache.

With the above approach, the cache does not reduce bandwidth on your internal network. Both cache hits and misses use internal bandwidth between users and the cache. Also, response-time benefits from cache hits may be lost if the internal network is congested. If you have a large internal network, then you may want to build an internal cache hierarchy. Place child caches on department-level networks and configure them to forward cache misses to a company-wide parent cache. With caches closer to users, you should observe reduced internal bandwidth and fast response times for cache hits.

ISPs often have points-of-presence (POPs) in different cities or locations. To reduce wide-area bandwidth usage, it’s a good idea to put a cache in each POP.