Popularity-based selective replication in content delivery network

Abstract

A client requests an object at a first server in a content delivery network (CDN), the request having been directed to said first server regardless of whether the first server has the requested object; When the first server does not have a copy of the requested object, it selectively replicating the requested object on the first server. The replicating is based at least in part on a measure of popularity of the requested object, wherein the requested object is not replicated to the first server when the measure of popularity of the requested object does not exceed a popularity threshold.

1 . A method in a distributed computing environment having a plurality of edge servers and at least one parent server, wherein the edge servers are arranged in hierarchical fashion relative to the at least one parent server, the plurality of edge content servers and the at least one parent server forming a content delivery network (CDN), the method comprising: 
 directing a request by a client for an object to a first edge server in the CDN; and    if a copy of the requested object is stored on the first edge server, serving the requested object to the client from the first edge server; and,    if a copy of the requested object is not stored on the first edge server, directing the client to a parent server in the CDN associated with the first edge server for delivery of the requested object therefrom and determining whether to replicate the requested object on the first edge server for use in serving future client requests based on a measure of popularity of the requested object.    
   
   
       2 . A method as recited in  claim 1 , further comprising: 
 replicating the requested object on the first edge server when the measure of popularity of the requested object exceeds a popularity threshold.    
   
   
       3 . A method as recited in  claim 2 , wherein the measure of popularity is defined based on a total number of client requests for the object received at the first edge server.  
   
   
       4 . A method as recited in  claim 1 , wherein if the parent server associated with the first edge server does not have a copy of the requested object, directing the client to another server in the CDN.  
   
   
       5 . A method as recited in  claim 4 , wherein the step of directing is repeated for a plurality of other servers in the CDN.  
   
   
       6 . A method as recited in  claim 4 , wherein the other server to which the client is directed if the parent server associated with the first edge server does not have a copy of the requested object is another parent server in the CDN.  
   
   
       7 . A method as recited in  claim 1 , wherein the distributed computing environment further comprises at least one origin server, the method further comprising: 
 if a copy of the requested object is not stored on the parent server associated with the first edge server, directing the client to at least one origin server for delivery of the requested object therefrom and determining whether to replicate the requested object on the parent server associated with the first edge server for use in serving future client requests based on a measure of popularity of the requested object.    
   
   
       8 . A method as recited in  claim 1 , wherein the measure of popularity of the requested object is a dynamic measure of popularity.  
   
   
       9 . A method as recited in  claim 1 , wherein the requested object is a streaming media object.  
   
   
       10 . A method, in a framework in which multiple resources of multiple content providers are delivered to multiple end user clients via a shared content delivery network (CDN) formed of a plurality of CDN server sites, each server site comprising one or more servers, the method comprising: 
 causing a client request for a resource to be directed to a first server site in said CDN;    if the first server site has a copy of the requested resource, then serving the requested resource to the client from the first server site; otherwise,    if the first server site does not have a copy of the requested resource, determining a measure of popularity of the requested resource relative to the first server site and replicating the requested resource to the first server site if the determined measure of popularity meets or exceeds a popularity threshold associated with the requested resource.    
   
   
       11 . A method as recited in  claim 10 , further comprising: 
 if the first server site does not have a copy of the requested resource, causing the client to be directed to a second server site in the CDN.    
   
   
       12 . A method as recited in  claim 11 , further comprising: 
 attempting to serve the requested resource to the client from the second server site in the CDN.    
   
   
       13 . A method as recited in  claim 10 , wherein the measure of popularity of the requested resource is a dynamic measure of popularity.  
   
   
       14 . A method, in a framework in which multiple resources of a content provider are delivered to multiple end user clients via a content delivery network (CDN) formed of a plurality of CDN server sites, each server site comprising one or more servers, wherein at least some of the CDN server sites are edge server sites each comprising one or more edge servers, and wherein at least some others of the CDN sites are parent server sites each comprising one or more parent servers, the method comprising: 
 (A) responsive to a client request for a resource at an edge server site in said CDN; and    (B) if the edge server site has a copy of the requested resource, then serving the requested resource to the client from the edge server site; otherwise,    (C) replicating a copy of the requested resource on the edge server site if a measure of popularity of the requested resource exceeds a popularity threshold associated with the requested object, otherwise not replicating the requested resource on the edge server site.    
   
   
       15 . A method as recited in  claim 13 , further comprising: 
 (D) if the edge server site does not have a copy of the requested resource, then attempting to serve the requested object to the client from a second server site in the CDN.    
   
   
       16 . A method as recited in  claim 15 , wherein the second server site in the CDN has a copy of the requested resource.  
   
   
       17 . A method as recited in  claim 13 , wherein the measure of popularity of the requested resource is a dynamic measure of popularity.  
   
   
       18 . A method, in a framework in which multiple resources of a content provider are delivered to multiple end user clients via a content delivery network (CDN), the CDN being formed of a plurality of edge servers and at least one parent server, wherein the edge servers are arranged in hierarchical fashion relative to the at least one parent server, the method comprising: 
 responsive to a client request for a resource at a first edge server in said CDN, determining if a copy of the requested resource is stored on the first edge server and, if not, then replicating a copy of the requested resource on the first edge server if a measure of popularity of the requested resource exceeds a popularity threshold associated with the requested object.    
   
   
       19 . A method as recited in  claim 18 , wherein if the first edge server does not have a copy of the requested resource, the method comprises: 
 attempting to serve the requested resource to the client from another server in the CDN, distinct from the first edge server.    
   
   
       20 . A method as recited in  claim 18 , further comprising: 
 directing the client to the other server in the CDN for delivery of the requested resource therefrom.    
   
   
       21 . A method as recited in  claim 20 , wherein the other server in the CDN is a parent server to which the first edge server is associated.  
   
   
       22 . A method as recited in  claim 21 , wherein the framework further comprises at least one origin server associated with the content provider, the method further comprising: 
 if a copy of the requested object is not stored on the parent server associated with the first edge server, directing the client to at least one origin server for delivery of the requested object therefrom and determining whether to replicate the requested object on the parent server associated with the first edge server for use in serving future client requests based on a measure of popularity of the requested object.    
   
   
       23 . A content delivery method comprising: 
 in response to a client request at a first server in a content delivery network (CDN), said request being for an object, said client request having been directed to said first server regardless of whether the first server has the requested object, when the first server does not have a copy of the requested object, determining whether to replicate the requested object on the first server based at least in part on comparing a measure of popularity of the requested object against a popularity threshold associated with the requested object.    
   
   
       24 . A method as recited in  claim 23 , further comprising: 
 replicating the requested object on the first server when the measure of popularity of the requested object exceeds the popularity threshold.    
   
   
       25 . A method as recited in  claim 24 , wherein the measure of popularity is defined based on a total number of client requests for the object received at the first server.