Dynamic request rerouting

• US 9,591,053 B2
• Filed: 04/11/2014
• Issued: 03/07/2017
• Est. Priority Date: 09/18/2013
• Status: Active Grant

• Current Assignee: Limelight Networks, Inc.
• Original Assignee: Limelight Networks, Inc.
• Inventors: Willbanks, John
• Primary Examiner(s): Higa, Brendan
• Application Number:
  US14/251,076
• Publication Number:
  US 20150081848A1
• Time in Patent Office: 1,061 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0482 Interaction with lists of selectable items, e.g. menus
• CPC Class Codes: G06F 40/174 Form filling; Merging
• CPC Class Codes: H04L 43/08 Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
• CPC Class Codes: H04L 43/0817 by checking functioning
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• 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: H04W 12/08 Access security

Abstract

A point of presence includes edge servers having IP addresses and storing content, a switch/router that receives and forwards requests for content to the edge servers, a health monitoring server that gathers health information from the edge servers, and a dynamic request rerouting (DRR) server. The DRR server is connected with each of the edge servers. If the DRR server obtains a determination that one of the edge servers is down, it advertises a route including the IP address of the down edge server to the switch/router. The switch/router forwards a request for content, originally addressed to the down server, to the DRR server. The DRR server forwards the request to a working server that stores the content. The working server sends the content to the DRR server, the DRR server forwards the content back to the switch/router, and the switch/router responds to the original request with the content.

Claims

1. A point of presence for a content delivery network that supports dynamic request rerouting, comprising:

a plurality of edge servers that store content objects, each of the edge servers being addressable through an IP address;

a switch/router that is operatively configured to receive a request for requested content and forward each such request to an appropriate one of the edge servers;

a health monitoring server that gathers health information from each of the edge servers; and

a dynamic request rerouting (DRR) server that is operatively connected with each of the plurality of edge servers, such that upon the DRR server obtaining a status determination that one of the edge servers is not operating properly, based on the health information;

the DRR server advertises a route that includes the IP address of the one of the edge servers that is not operating properly, to the switch/router,

the switch/router forwards an original request for requested content that was originally addressed to the one of the edge servers that is not operating properly, to the DRR server,

the DRR server forwards the request to one of the edge servers that is operating properly and stores the requested content,

the one of the edge servers that is operating properly responds by sending the requested content to the DRR server;

the DRR server forwards the requested content back to the switch/router; and

the switch/router responds to the original request with the requested content.

2. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the health monitoring server generates and forwards the status determination to the DRR server.

3. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the health monitoring server aggregates and forwards the health information to the DRR server without generating the status determination.

4. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the health information comprises native status or health check information that is available from the edge servers.

5. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the health information comprises one or more measurements of response time to content requests.

6. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the DRR server comprises a health ingest layer that receives the health information, a routing rules layer that generates IP addresses to reroute traffic originally sent to the one of the edge servers that is not operating properly, and a route injection layer that writes the IP addresses to appropriate ports to perform the rerouting.

7. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the health monitoring server, the DRR server and the switch/router are configured to detect the one of the edge servers that is not operating properly, and to reconfigure the point of presence to implement a path to the one of the edge servers that is operating properly, in five seconds or less.

8. The point of presence for a content delivery network that supports dynamic request rerouting of claim 1, wherein the health monitoring server, the DRR server and the switch/router are configured to detect the one of the edge servers that is not operating properly, and to reconfigure the point of presence to implement a path to the one of the edge servers that is operating properly, in less than a time-to-live previously established for the one of the edge servers that is not operating properly.

9. A method of dynamic request rerouting in a point of presence for a content delivery network, comprising:

receiving content requests at a switch/router that can be served by a plurality of edge servers of the point of presence, each of the edge servers being associated with an IP address;

accumulating health information for the plurality of edge servers of the point of presence at a health monitoring server;

determining from the health information that one of the edge servers is not operating properly;

advertising, by a dynamic request reroute (DRR) server coupled with the health monitoring server, a route for the IP address of the edge server that is not operating properly, to the switch/router;

forwarding one of the content requests that is addressed to the server that is not operating properly, to the DRR server in response to the route advertising;

forwarding the content request that is addressed to the server that is not operating properly through the DRR server to a different one of the plurality of edge servers that is operating properly and can serve the content request; and

forwarding content from the one of the plurality of edge servers that is operating properly through the DRR server and the switch/router to serve the original content request.

10. The method of dynamic request rerouting in a point of presence of a content delivery network of claim 9, wherein determining from the health information that one of the edge servers is not operating properly comprises generating, by the health monitoring server, a status determination based on the health information from each of the edge servers, and forwarding the status determination from the health monitoring server to the DRR server.

11. The method of dynamic request rerouting in a point of presence of a content delivery network of claim 9, wherein accumulating health information for the plurality of edge servers of the point of presence at the health monitoring server comprises aggregating and forwarding the health information from the health monitoring server to the DRR server without generating a status determination at the health monitoring server.

12. The method of dynamic request rerouting in a point of presence of a content delivery network of claim 9, wherein accumulating health information for the plurality of edge servers of the point of presence comprises accumulating one or more of native status information that is available from the edge servers, health check information that is available from the edge servers, and one or more measurements of response time to content requests.

13. The method of dynamic request rerouting in a point of presence of a content delivery network of claim 9, wherein:

the health monitoring server, the DRR server and the switch fabric cooperate to detect the edge server that is not operating properly, and

the DRR advertises the route for the IP address of the edge server that is not operating properly, to the switch/router,

in five seconds or less.

14. The method of dynamic request rerouting in a point of presence of a content delivery network of claim 9, wherein:

the health monitoring server, the DRR server and the switch fabric cooperate to detect the one of the edge servers that is not operating properly, and

the DRR advertises the route for the IP address of the one of the edge servers that is not operating properly, to the switch/router,

in less time than a time-to-live previously established for the one of the edge servers that is not operating properly.

15. A computer software product, comprising non-transitory computer-readable media having instructions stored therein, wherein the instructions, when executed by one or more servers of a point of presence of a content delivery network, cause the servers to implement a method of dynamic request rerouting in the point of presence of the content delivery network, the instructions comprising:

instructions for receiving content requests at a switch/router that can be served by a plurality of edge servers of the point of presence, each of the edge servers being associated with an IP address;

instructions for accumulating health information for the plurality of edge servers of the point of presence at a health monitoring server;

instructions for determining from the health information that one of the edge servers is not operating properly;

instructions for advertising, by a dynamic request reroute (DRR) server coupled with the health monitoring server, a route for the IP address of the edge server that is not operating properly, to the switch/router;

instructions for forwarding one of the content requests that is addressed to the server that is not operating properly, to the DRR server in response to the route advertising;

instructions for forwarding the content request that is addressed to the server that is not operating properly through the DRR server to a different one of the plurality of edge servers that is operating properly and can serve the content request; and

instructions for forwarding content from the one of the plurality of edge servers that is operating properly through the DRR server and the switch/router to serve the original content request.

16. The computer software product of claim 15, wherein the instructions for determining from the health information that one of the edge servers is not operating properly comprises instructions for:

generating, by the health monitoring server, a status determination based on the health information from each of the edge servers, and

forwarding the status determination from the health monitoring server to the DRR server.

17. The computer software product of claim 15, wherein the instructions for accumulating health information for the plurality of edge servers of the point of presence at the health monitoring server comprise instructions for aggregating and forwarding the health information from the health monitoring server to the DRR server without generating a status determination at the health monitoring server.

18. The computer software product of claim 15, wherein the instructions for accumulating health information for the plurality of edge servers of the point of presence comprise instructions for accumulating one or more of native status information that is available from the edge servers, health check information that is available from the edge servers, and one or more measurements of response time to content requests.