Content request routing method

Abstract

A method of redirecting content requests among content distribution network peers. In operation, a client sends a request for content to a content distribution network (CDN). When this CDN does not currently have the capacity to deliver the content, the CDN refers to one or more content distribution tables to see if the neighbour peers are able to provide this content. The content distribution table is populated at the time of distribution of the content. When the neighbour peer has this content, the request is redirected to the neighbour peer. In redirecting request, an address of the neighbour peer is appending to the previous address such that each peer receiving the request knows where the request came from and where it has been previously.

What is claimed is: 
     
         1 . A method of redirecting content requests among peer content distribution network nodes, the method comprising:
 providing, at a first content distribution network node, information identifying content contained on each peer content distribution network node of the first content distribution network node;   receiving, at the first content distribution network node, a content request comprising an identification of requested content;   responsive to a determination that the first content distribution network node will refuse the content request, determining, from the information identifying the content contained on each peer content distribution network node of the first content distribution network node, whether a second content distribution network node is a candidate for providing the requested content; and   when the second content distribution network node is the candidate for providing the requested content, redirecting the content request from the first content distribution network node to the second content distribution network node.   
     
     
         2 . The method of  claim 1 , wherein:
 when the content request received by the first content distribution network node has been refused by at least one refusing content distribution network node, the content request received by the first content distribution network node comprises information identifying the at least one refusing content distribution network node; and   determining whether the second content distribution network node is the candidate for providing the requested content comprises determining, from the information identifying the content contained on each peer content distribution network node of the first content distribution network node and from the information identifying the at least one refusing content distribution network node, whether the second content distribution network node contains the requested content and is not a refusing content distribution network node.   
     
     
         3 . The method of  claim 2 , wherein determining whether the second content distribution network node is the candidate for providing the requested content comprises:
 determining, from the information identifying the content contained on each peer content distribution network node of the first content distribution network node and from the information identifying the at least one refusing content distribution network node, a plurality of peer content distribution network nodes that contain the requested content and that are not refusing content distribution network nodes; and   selecting one of the plurality of peer content distribution network nodes as the second content distribution network node.   
     
     
         4 . The method of  claim 3 , wherein redirecting the content request from the first content distribution network node to the second content distribution network node comprises adding, to the information identifying the at least one refusing content distribution network node of the redirected content request, information identifying the first content distribution network node as a refusing content distribution network node. 
     
     
         5 . The method of  claim 4 , wherein:
 the content request received by the first content distribution network node comprises an address associated with the first content distribution network node;   the information identifying the at least one refusing content distribution network node is encoded in the address; and   adding, to the information identifying the at least one refusing content distribution network node of the redirected content request, the information identifying the first content distribution network node as a refusing content distribution network node comprises adding information identifying the first content distribution network node to the address of the content request redirected to the second content distribution network node.   
     
     
         6 . The method of  claim 5 , wherein the address comprises a set of refusing content distribution network node identifiers. 
     
     
         7 . The method of  claim 6 , wherein the set is ordered according to an order in which the refusing content distribution network nodes refused the content request. 
     
     
         8 . The method of  claim 6 , wherein the address is a uniform resource locator. 
     
     
         9 . The method of  claim 2 , wherein:
 the content request received by the first content distribution network node comprises an address associated with the first content distribution network node; and   the information identifying the at least one refusing content distribution network node is encoded in the address.   
     
     
         10 . The method of  claim 9 , wherein the address comprises a set of refusing content to distribution network node identifiers. 
     
     
         11 . The method of  claim 10 , wherein the set is ordered according to an order in which the refusing content distribution network nodes refused the content request. 
     
     
         12 . The method of  claim 10 , wherein the address is a uniform resource locator. 
     
     
         13 . The method of  claim 1 , wherein determining whether the second content distribution network node is the candidate for providing the requested content comprises determining that no peer content distribution network node is a candidate for providing the requested content. 
     
     
         14 . The method of  claim 13 , comprising sending a content request refusal message indicating that the requested content will not be provided. 
     
     
         15 . The method of  claim 13 , wherein:
 when the content request received by first content distribution network node has been refused by at least one refusing content distribution network node, the content request received by the first content distribution network node comprises information identifying the at least one refusing content distribution network node; and   determining that no peer content distribution node is a candidate for providing the requested content comprises determining, from the information identifying the content contained on each peer content distribution node of the first content distribution node and from the information identifying the at least one refusing content distribution network node, that no peer content distribution network node both contains the requested content and is not a refusing content distribution network node.   
     
     
         16 . The method of  claim 15 , wherein:
 the content request received by the first content distribution network node comprises an address associated with the first content distribution network node; and   the information identifying the at least one refusing content distribution network node is encoded in the address.   
     
     
         17 . The method of  claim 16 , wherein the address comprises a set of refusing content distribution network node identifiers. 
     
     
         18 . The method of  claim 17 , wherein the set is ordered according to an order in which the refusing content distribution network nodes refused the content request. 
     
     
         19 . The method of  claim 17 , wherein the address is a uniform resource locator. 
     
     
         20 . The method of  claim 1 , wherein redirecting the content request from the first content distribution network node to the second content distribution network node comprises adding to the content request an indication that the content request was refused by the first content distribution network node. 
     
     
         21 . The method of  claim 1 , wherein the content request received by the first content distribution network node comprises an address associated with the first content distribution network node. 
     
     
         22 . The method of  claim 1 , wherein providing the information identifying the content contained on each peer content distribution network node of the first content distribution network node comprises providing at least one distribution table at the first content distribution network node, the at least one distribution table associating content items with peer content distribution network nodes containing the content items. 
     
     
         23 . The method of  claim 22 , wherein providing the at least one distribution table at the first content distribution network node comprises providing a separate distribution table for each of a plurality of content items on the first content distribution network node. 
     
     
         24 . The method of  claim 22 , wherein:
 the at least one content distribution table at the first content distribution network node lists the peer content distribution network nodes according to a peering hierarchy; and   when a plurality of peer content distribution network nodes contains the requested content and does not comprise refusing content distribution network nodes, the first content distribution network node preferentially selects the second content distribution network node based on the peering hierarchy.