This image must be delivered to a browser user every time the browser accesses one of Amazon's pages, and these pages are requested tens of thousands of times a day. On subsequent requests for the same object, the cache delivers the object from its storage rather than passing the request on to the origin server. The higher the number of people requesting the same object during its useful life, the more upstream traffic the cache eliminates. By handling object requests rather than passing them upstream to the origin server, caches reduce network traffic and improve the browsing experience for users. 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.
Caches come in all sizes.
Contents Quality of service Web object requests that come from long distances can take longer to satisfy because there are more network routers to be traversed between browser and server, and any router in the path can become overwhelmed with traffic. A cache located closer to the browser delivers frequently requested content through fewer routers, thus reducing the potential for packet loss delays and speeding overall service. And because there are fewer service delays between a cache and a browser, a cache increases the transmission bandwidth to the browser for cached objects. With a streaming media object, for example, a cache detecting a 1 MBit connection to a browser will serve the media to the browser at that speed. On the other hand, a media server located across the country would detect less available bandwidth for the distance to the browser, and would therefore serve the object at a much slower speed, reducing the quality of the browser user's experience.