Distributed Selection of a Content Server

Abstract

A method for directing a client to a content server containing desired content by providing the client with an address shared by a plurality of content servers, each of which has a copy of the desired content. The client is then served from an optimal, or closest available content server selected from the plurality of content servers. This optimal content server is selected on the basis of an optimal path from the client to the shared address.

1 . A method for directing a client to a content server containing desired content, said method comprising:
 providing said client with a shared address, said shared address being common to a plurality of content servers, each of said content servers having a copy of said desired content; and   serving said client from an optimal content server selected from said plurality of content servers, said optimal content server having been selected on the basis of an optimal path from said client to said shared address.   
     
     
         2 . The method of  claim 1  wherein serving said client from an optimal content server comprises:
 receiving a request from said client to connect to a content server at said shared address;   identifying an optimal path between said client and said shared address; and   designating a content-server on said optimal path to be said optimal content-server   
     
     
         3 . The method of  claim 2  further comprising directing said client to reach said optimal content-server by following said optimal path. 
     
     
         4 . The method of  claim 1  further comprising grouping said plurality of content servers into an autonomous system. 
     
     
         5 . The method of  claim 4  further comprising providing said shared address to a BGP router. 
     
     
         6 . A content delivery system comprising:
 a first content server and a second content server having content in common with said first content server, said first and second content servers having a shared address;   a first router for relaying messages to said first content server; and   a second router for relaying messages to said second content server.   
     
     
         7 . The content delivery system of  claim 6  further comprising an autonomous system containing said first and second content servers. 
     
     
         8 . The content delivery system of  claim 6  wherein said first router is a BGP router. 
     
     
         9 . The content delivery system of  claim 1  further comprising an origin server for providing said shared address in response to a request for content. 
     
     
         10 . A computer-readable medium having encoded thereon software for directing a client to a content server containing desired content, said software comprising instructions for:
 providing said client with a shared address, said shared address being common to a plurality of content servers, each of said content servers having a copy of said desired content; and   serving said client from an optimal content server selected from said plurality of content servers, said optimal content server having been selected on the basis of an optimal path from said client to said shared address.   
     
     
         11 . The method of  claim 10  wherein said instructions for serving said client from an optimal content server comprise instructions for:
 receiving a request from said client to connect to a content server at said shared address;   identifying an optimal path between said client and said shared address; and   designating a content-server on said optimal path to be said optimal content-server   
     
     
         12 . The method of  claim 11  wherein said software further comprises instructions for directing said client to reach said optimal content-server by following said optimal path. 
     
     
         13 . The method of  claim 10  said software further comprises instructions for grouping said plurality of content servers into an autonomous system. 
     
     
         14 . The method of  claim 13  said software further comprises instructions for said shared address to a BGP router.