Many users request the same popular pages and objects. This page may be requested millions of times a day, which creates heavy server demand and a lot of network traffic, increasing page load times. A cache is a dedicated set of hardware and software that monitors Web content and object requests and stores them after retrieving them from a server. When the same content and objects are requested again, the cache delivers the object from its storage rather than passing the request to the Web server. This speeds up content delivery and response time while reducing the Web server's workload.
Web objects change over time, so each object has a limited life span.
Caches can be located anywhere on a network, and each cache will store a different set of objects based on the needs of the users it serves. Some software-only vendors partner with hardware manufacturers to create appliances. Novell's Internet Caching System is a software-only solution, but it's often installed on hardware sold by Dell. Cache Appliance is powered by Inktomi Corp.'s Traffic Server Engine. A company can also buy a prepackaged appliance, such as Compaq's TaskSmart Servers.