Content delivery network map generation using passive measurement data

• US 7,007,089 B2
• Filed: 06/06/2002
• Issued: 02/28/2006
• Est. Priority Date: 06/06/2001
• Status: Active Grant

• Current Assignee: Akamai Technologies, Inc.
• Original Assignee: Akamai Technologies, Inc.
• Inventors: Freedman, Avraham T.
• Primary Examiner(s): Follansbee, John
• Assistant Examiner(s): LIN, KENNY S
• Application Number:
  US10/163,969
• Publication Number:
  US 20030002484A1
• Time in Patent Office: 1,363 Days
• Field of Search: 709/228, 709/238, 709/231, 709/226, 370/252, 370/351, 370/228, 718/105
• US Class Current: 709/225
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 45/70 Routing based on monitoring results
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A routing method operative in a content delivery network (CDN) where the CDN includes a request routing mechanism for routing clients to subsets of edge servers within the CDN. According to the routing method, TCP connection data statistics are collected are edge servers located within a CDN region. The TCP connection data statistics are collected as connections are established between requesting clients and the CDN region and requests are serviced by those edge servers. Periodically, e.g., daily, the connection data statistics are provdied from the edge servers in a region back to the request routing mechanism. The TCP connection data statistics are then used by the request routing mechanism in subsequent routing decisions and, in particular, in the map generation processes. Thus, for example, the TCP connection data may be used to determine whether a given quality of service is being obtained by routing requesting clients to the CDN region. If not, the request routing mechanism generates a map that directs requesting clients away from the CDN region for a given time period or until the quality of service improves.

Claims

1. A routing method operative in a content delivery network (CDN) having a request routing mechanism for routing clients to edge servers, comprising:

at edge servers located within a CDN region, collecting TCP connection data statistics as connections are established between requesting clients and the CDN region and requests are serviced by the edge servers;

providing the TCP connection data statistics from the edge servers to the request routing mechanism;

at the request routing mechanism, using the TCP connection data statistics to determine whether a given quality of service is being obtained by routing requesting clients to the CDN region; and

if the given quality of service is not being obtained, directing requesting clients away from the CDN region;

wherein the requesting clients are directed away from the CDN region until the TCP connection data statistics indicate that the given quality of service is being obtained.

2. The routing method as described in claim 1 wherein the TCP connection data statistics are aggregated over a given time period.

3. The routing method as described in claim 2 wherein the TCP connection data statistics are aggregated with connection data from each of the edge servers co-located in the CDN region over the given time period.

4. The routing method as described in claim 1 wherein the requesting clients are directed to at least one other CDN region if the quality of service is not being obtained.

5. The routing method as described in claim 1 wherein the step of directing requesting clients away from the CDN region comprises:

generating a routing decision to bias a given client request to another CDN region associated with a higher quality of service.

6. The method as described in claim 1 wherein the request routing mechanism includes a map that associates Internet Protocol (IP) address blocks to CDN regions and that is used to respond to DNS queries.

7. The method as described in claim 6 further including the step of modifying the map as a function of the TCP connection data statistics.

8. The method as described in claim 1 wherein the TCP connection data statistics are collected on a per edge server basis.

9. The method as described in claim 1 wherein the TCP connection data statistics are collected on a per requesting client basis.

10. The method as described in claim 1 wherein the TCP connection data statistics are collected on a per URL basis.

11. The method as described in claim 1 wherein the step of using the TCP connection data statistics to determine whether a given quality of service is being obtained further includes analyzing the TCP connection data statistics on one of:

a per CIDR block basis, a per prefix basis, or a per autonomous system (AS) basis.

12. The routing method as described in claim 1 wherein the TCP connection data statistics are collected on a per connection basis.

13. The routing method as described in claim 12 wherein the TCP connection data statistics are collected on a per HTTP connection basis.

14. The routing method as described in claim 1 wherein the TCP connection data is collected for a configurable percentage of client requests to a given edge server.