Method and system for tiered distribution in a content delivery network

• US 7,376,716 B2
• Filed: 11/06/2006
• Issued: 05/20/2008
• 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:
  US11/593,287
• Publication Number:
  US 20070055764A1
• Time in Patent Office: 561 Days
• Field of Search: 709217-219, 709/203, 709/214, 709223-224, 709/220, 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 server operating in a content delivery network (CDN) having an authoritative domain name service (DNS) and a set of servers organized into regions that provide content delivery on behalf of participating content providers, wherein the CDN also includes a set of CDN cache hierarchy nodes, comprising:

a processor;

an operating system;

a cache;

memory in which content provider-specific metadata is stored, the content provider-specific metadata describing content handling requirements for given content provider content, the content provider-specific metadata also identifying a source server for the given content provider content;

code executable by the processor for determining whether a given object request can be serviced from the cache, the given object request associated with a first data string that has been resolved by the authoritative DNS to identify the server;

code executable by the processor and responsive to a determination that the given object request cannot be serviced from the cache for evaluating content provider-specific metadata to determine whether the given object request is to be serviced by a CDN cache hierarchy node;

code executable by the processor and responsive to a determination that the given object request is to be serviced by a CDN cache hierarchy node for rewriting the first data string associated with the given object request into a second data string that points to the set of CDN cache hierarchy nodes, the second data string being resolvable by the authoritative DNS to identify a given CDN cache hierarchy node intermediate the server and a source server identified in the content provider-specific metadata; and

code executable by the processor and responsive to resolution of the second data string by the authoritative DNS to forward for handling the given object request to the given CDN cache hierarchy node.

2. The server as described in claim 1 wherein the second data string is of the form aSerial.rRegion.cdnsp.net, where cdnsp.net is resolvable by the CDN authoritative DNS.

3. The server as described in claim 1 wherein the content provider-specific metadata is settable on a per-object basis.

4. The server as described in claim 1 further including code executable by the processor to receive a response from the given CDN cache hierarchy node.

5. The server as described in claim 4 wherein the response includes a content object associated with the given object request.

6. The server as described in claim 5 wherein the response from the given CDN cache hierarchy node also includes time-to-live (TTL) information for the content object.

7. The server as described in claim 1 further including code executable by the processor to rewrite a request header associated with the given object request prior to forwarding the given object request to the given CDN cache hierarchy node.