P2P caching

Peer-to-peer caching (P2P caching) is a <a href="/facts/Computer_network/3w5RM99p">computer network</a> traffic management technology used by <a href="/facts/Internet_Service_Providers/dUacAxef">Internet Service Providers</a> (ISPs) to accelerate content delivered over <a href="/facts/Peer-to-peer/wCCdPb0H">peer-to-peer</a> (P2P) networks while reducing related bandwidth costs.
P2P <a href="/facts/Cache_(computing)/gmJYN8wm">caching</a> is similar in principle to the content caching long used by ISPs to accelerate Web (<a href="/facts/HTTP/TWtvf7JD">HTTP</a>) content. P2P caching temporarily stores popular content that is flowing into an ISP's network. If the content requested by a subscriber is available from a cache, the cache satisfies the request from its temporary storage, eliminating data transfer through expensive transit links and reducing <a href="/facts/Network_congestion/9ohkRMso">network congestion</a>. This approach could make ISPs violate laws as P2P systems share files that infringe copyrights in significant portions.
P2P content responds well to caching because it has high reuse patterns reflecting a <a href="/facts/Zipf%27s_law/bspk1du8">Zipf's</a>-like distribution. P2P communities have different Zipf's parameters which determine what fraction of files is requested multiple times. For example, one P2P community may request 75% of content multiple times while another may request only 10%.
Some P2P caching devices can also accelerate HTTP video streaming traffic from <a href="/facts/YouTube/db276jst">YouTube</a>, <a href="/facts/Facebook/0IhXFR6u">Facebook</a>, <a href="/facts/RapidShare/DbCkAJcC">RapidShare</a>, <a href="/facts/MegaUpload/JK44HkGh">MegaUpload</a>, <a href="/facts/Google/GT9Sugza">Google</a>, <a href="/facts/AOL_Video/MAbT38QS">AOL Video</a>, <a href="/facts/MySpace/dES860Ro">MySpace</a> and other web video-sharing sites.

P2P caching open-in-new

P2P caching