Method and system for tiered distribution in a content delivery network

• US 7,133,905 B2
• Filed: 04/09/2002
• Issued: 11/07/2006
• Est. Priority Date: 04/09/2002
• Status: Expired due to Term

• Current Assignee: Akamai Technologies, Inc.
• Original Assignee: Akamai Technologies, Inc.
• Inventors: Berkheimer, Andrew D., Dilley, John A.
• Primary Examiner(s): Tran, Philip B.
• Application Number:
  US10/118,989
• Publication Number:
  US 20030233423A1
• Time in Patent Office: 1,673 Days
• Field of Search: 709/203, 709217-219, 709/223, 709/226, 709213-214, 711/122
• US Class Current: 709/219
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 67/2885 Hierarchically arranged intermediate devices, e.g. for hierarchical caching
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/5651 Reducing the amount or size of exchanged application data
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 4/02 Services making use of location information

Abstract

A tiered distribution service is provided in a content delivery network (CDN) having a set of surrogate origin (namely, “edge”) servers organized into regions and that provide content delivery on behalf of participating content providers, wherein a given content provider operates an origin server. According to the invention, a cache hierarchy is established in the CDN comprising a given edge server region and either (a) a single parent region, or (b) a subset of the edge server regions. In response to a determination that a given object request cannot be serviced in the given edge region, instead of contacting the origin server, the request is provided to either the single parent region or to a given one of the subset of edge server regions for handling, preferably as a function of metadata associated with the given object request. The given object request is then serviced, if possible, by a given CDN server in either the single parent region or the given subset region. The original request is only forwarded on to the origin server if the request cannot be serviced by an intermediate node.

Claims

1. A method operative in a content delivery network (CDN) having a set of surrogate origin servers organized into regions and that provide content delivery on behalf of participating content providers, wherein a given content provider operates an origin server, comprising:

establishing a cache hierarchy in the CDN comprising a given surrogate origin server region and one of;

(a) a single parent region located in a given location, and (b) a subset of parent regions located in given core Internet locations;

in response to a determination that a given object request cannot be serviced in the given surrogate origin server region, directing the given object request to the single parent region or to a given one of the subset of parent regions instead of to an origin server, wherein the directing step is based on content provider-specific metadata associated with the given object request and includes the sub-steps of rewriting a first data string associated with the given obiect request into a second data string that points to the cache hierarchy and resolving the second data string, wherein if the directing step directs the given object request to one of the subset of parent regions, the second data string is resolved to identify a best core region and an optimal server in the best core region to service the given object request; and

attempting to service the given object request in the single parent region or the given one of the subset of parent regions as determined by the directing step.

2. The method as described in claim 1 further including the step of:

if, as a result of the attempting step, the given object request still cannot be serviced, forwarding the given object request back to the origin server.

3. The method as described in claim 1 wherein the content provider-specific metadata associated with the given object request indicates that the given object is a candidate far delivery via the cache hierarchy.

4. The method as described in claim 1 wherein the content provider-specific metadata is identified by a given entity and further including the step of delivering the content provider-specific metadata to the given surrogate origin server region.

5. The method as described in claim 4 wherein the single parent region is associated with a given content provider.

6. The method as described in claim 5 wherein the single parent region is co-located with the origin server of the given content provider.

7. The method as described in claim 1 further including the step of attempting to service the given object request from a peer in the given surrogate origin server region prior to directing the request to the singe parent region or to a given one of the subset of parent regions.

8. The method as described in claim 1 wherein a first participating content provider uses the single parent region and a second participating content provider uses a subset of the parent regions.

10. The method as described in claim 1 further including:

if, as a result of the attempting step the given object request still cannot be serviced, forwarding the given object request to a backing server in the cache hierarchy.

11. The method as described in claim 1 further including the step of maintaining a persistent connection between the cache hierarchy and the origin server.

9. A method operative in a content delivery network having a set of surrogate origin servers organized into regions and that provide content delivery on behalf of participating content providers, wherein a given content provider operates an origin server, comprising:

establishing a cache hierarchy in the CDN comprising a given surrogate origin server region and one of;

(a) a single parent region, and (b) a subset of the parent server regions;

in response to a determination that a given object request cannot be serviced in the given surrogate origin server region, attempting to service the request from a peer in the given surrogate origin server region;

if the request cannot be serviced from a peer in the given surrogate origin server region, providing the given object request to the single parent region or to a given one of the subset of parent regions instead of to an origin server, wherein the providing step is based on content provider-specific metadata associated with the given object request and includes the sub-steps of rewriting a first data string associated with the given object request into a second data string that points to the cache hierarchy and resolving the second data string, wherein if the directing step directs the given object request to one of the subset of parent regions, the second data string is resolved to identify a best core region and an optimal server in the best core region to service the given object request; and

attempting to service the given object request in the single parent region or the given one of the subset of parent regions as determined by the providing step.