Optimal route selection in a content delivery network

• US 8,194,538 B2
• Filed: 04/18/2011
• Issued: 06/05/2012
• Est. Priority Date: 03/01/2001
• Status: Expired due to Term

• Current Assignee: Akamai Technologies, Inc.
• Original Assignee: Akamai Technologies, Inc.
• Inventors: Bornstein, Claudson F., Canfield, Timothy K., Miller, Gary L., Rao, Satish B., Sundaram, Ravi
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): BOAKYE, ALEXANDER O
• Application Number:
  US13/088,517
• Publication Number:
  US 20110196943A1
• Time in Patent Office: 414 Days
• Field of Search: 370/227, 370/351, 370/235, 370/237, 370/238, 370/400, 370/401, 455/556.2, 455/414.1, 709/217, 709/122, 705/400, 705/51
• US Class Current: 370/227
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/26 Route discovery packet
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/289 Intermediate processing functionally located close to the data consumer application, e.g. in same machine, in same home or in same sub-network
• CPC Class Codes: H04L 67/55 Push-based network services
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/61 taking into account QoS or priority requirements
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A routing mechanism, service or system operable in a distributed networking environment. One preferred environment is a content delivery network (CDN) wherein the present invention provides improved connectivity back to an origin server, especially for HTTP traffic. In a CDN, edge servers are typically organized into regions, with each region comprising a set of content servers that preferably operate in a peer-to-peer manner and share data across a common backbone such as a local area network (LAN). The inventive routing technique enables an edge server operating within a given CDN region to retrieve content (cacheable, non-cacheable and the like) from an origin server more efficiently by selectively routing through the CDN'"'"'s own nodes, thereby avoiding network congestion and hot spots. The invention enables an edge server to fetch content from an origin server through an intermediate CDN server or, more generally, enables an edge server within a given first region to fetch content from the origin server through an intermediate CDN region.

Claims

1. A method operative in a content delivery network having a set of server nodes organized into regions, wherein the server nodes provide delivery of content on behalf of participating content providers, wherein a server node comprises a cluster of content delivery network edge servers, the method comprising:

for each given server node and a content provider origin server, identifying at least one alternate path to be used for edge server-to-content provider origin server communications, the at least one alternate path including at least one other content delivery network edge server that is external to the given server node;

upon receipt at a particular edge server in the given server node of a request for an object that is not available for delivery from the particular edge server, issuing a new request for the object from the particular edge server over the at least one alternate path, wherein the object has an associated cacheability setting, wherein the cacheability setting indicates that the object should not be cached in the particular edge server;

receiving the object over the at least one alternate path; and

serving the object in response to the request.

2. A method operative in a content delivery network having a set of server nodes organized into regions, wherein the server nodes provide delivery of content on behalf of participating content providers, wherein a server node comprises a cluster of content delivery network edge servers, the method comprising:

for each given server node and a content provider origin server, identifying at least one alternate path to be used for edge server-to-content provider origin server communications, the at least one alternate path including at least one other content delivery network edge server that is external to the given server node;

upon receipt at a particular edge server in the given server node of a request for an object that is not available for delivery from the particular edge server, issuing a new request for the object from the particular edge server over the at least one alternate path;

receiving the object over the at least one alternate path;

serving the object in response to the request; and

identifying a new alternate path as a result of changing Internet conditions.

3. The method as described in claim 2 wherein the alternate path is valid for a given time period.

4. The method as described in claim 2 wherein the at least one alternate path is other than a default Border Gateway Routing (BGP) path.

5. A method operative in a content delivery network having a set of server nodes organized into regions, wherein the server nodes provide delivery of content on behalf of participating content providers, wherein a server node comprises a cluster of content delivery network edge servers, the method comprising:

for each given server node and a content provider origin server, identifying at least one alternate path to be used for edge server-to-content provider origin server communications, the at least one alternate path including at least one other content delivery network edge server that is external to the given server node, wherein the alternate path is determined by the particular edge server as a result of performing a performance test;

upon receipt at a particular edge server in the given server node of a request for an object that is not available for delivery from the particular edge server, issuing a new request for the object from the particular edge server over the at least one alternate path;

receiving the object over the at least one alternate path; and

serving the object in response to the request.

6. The method as described in claim 5 wherein the performance test comprises a race, wherein the race comprises downloading a file to the particular edge server over at least the alternate path and a default Border Gateway Routing (BGP) path.

7. The method as described in claim 6 wherein the race is executed by the particular edge server upon receipt of the request for the object.

8. The method as described in claim 7 wherein the file that is downloaded during the race is also the object.