Proxy cache cluster

• US 6,330,605 B1
• Filed: 11/19/1998
• Issued: 12/11/2001
• Est. Priority Date: 11/19/1998
• Status: Expired due to Term

• Current Assignee: Micro Focus Software, Inc. (Open Text Corporation)
• Original Assignee: Volera
• Inventors: Harral, Adam Lee, Davis, Howard Rollin, Christensen, Brent Ray
• Primary Examiner(s): Eng, David Y.
• Application Number:
  US09/195,982
• Time in Patent Office: 1,118 Days
• Field of Search: 700/200, 700/203, 700/226, 700/233, 700/234, 700/235, 700/238, 700/239, 700/240, 700/241
• US Class Current: 709/226
• CPC Class Codes: H04L 61/50 Address allocation
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 67/1036 Load balancing of requests to servers for services different from user content provisioning, e.g. load balancing across domain name servers
• 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]

Abstract

A proxy cache cluster (PCC) couples to a service provider of a communications network to increase the availability of services offered by the provider to clients connected to the network. The clients access the services by issuing requests to network addresses associated with these services. The PCC increases the availability of the services by receiving and servicing those requests on behalf of the service provider in accordance with a proxy cache clustering technique.

Claims

1. A method for increasing the availability of services offered by a service provider to clients connected to a communications network, the clients accessing the services by issuing requests to service addresses associated with these services, the method comprising the steps of:

providing a plurality of processor/memory mechanisms (PMMs) adapted to cooperatively interact in order to receive and service the requests on behalf of the service provider;

organizing the PMMs as one or more proxy cache clusters (PPCs) by dynamically assigning each PMM to one or more PCCs;

balancing the service addresses among PMMs by assigning selected service addresses to each PMM of the PCC; and

rebalancing the service addresses among PMMs of the PCC in response to dynamic changes in the PCC.

2. The method of claim 1 wherein the step of organizing comprises the step of configuring each PMM with a unique identifier (ID), a network address and PCC configuration software.

3. The method of claim 2 wherein the step of organizing further comprises the step of notifying each PMM of availability in the PCC using a heartbeat message broadcasted to each member of the PCC.

4. The method of claim 3 wherein the step of organizing further comprises the step of sharing a common configuration among the PMMs that describes the PCC in terms of the PMMs, static PCC configuration parameters and hosted PCC services.

5. The method of claim 4 wherein the step of sharing a common configuration comprises the step of characterizing each hosted PCC service by a load rating value that reflects a measure of the PCC service'"'"'s resource consumption.

6. The method of claim 4 wherein the step of sharing a common configuration comprises the step of characterizing the hosted PCC services by service type.

7. The method of claim 6 wherein the service type comprises one of a Hypertext Transfer Protocol (HTTP) proxy service, an HTTP accelerator service, a file transfer protocol proxy service, real audio and real video.

8. The method of claim 4 wherein the step of sharing a common configuration comprises the step of characterizing the hosted PCC services by service type parameters that are unique to each service.

9. The method of claim 5 wherein the step of providing comprises the step of characterizing each PMM by a capacity rating value that reflects a measure of the PMM'"'"'s ability to provide resources.

10. The method of claim 1 wherein the step of balancing the service addresses comprises the step of designating a particular PMM to function as a PCC coordinator to assign the service addresses to the PMMs.

11. The method of claim 10 wherein the step of balancing the service addresses further comprises the step of periodically distributing a message containing the service address assignments from the PCC coordinator to the PMMs.

12. The method of claim 11 wherein the step of periodically distributing comprises the step of uniquely identifying the service address assignment message as issued by the PCC coordinator by marking the message with a stamp.

13. The method of claim 11 wherein the step of providing comprises the step of characterizing each PMM by a role that describes various activities of the PMM as manifested in one of the service address assignment message and the heartbeat message.

14. The method of claim 13 wherein the role comprises an active role in one or more PCCs that allows the PMM to participate in all PCC activities.

15. The method of claim 13 wherein the role comprises an standby role in one or more PCCs that prohibits assignments to the PMM until at least one other PMM in the PCC assumes one of a down or unusable role.

16. The method of claim 15 wherein the unusable role indicates that the PMM cannot be used by the PCC, whereas the down role is automatically assigned by the PCC coordinator upon failure to detect a heartbeat message within a predetermined period.

17. The method of claim 13 wherein the role comprises an active role in one or more PCCs that allows the PMM to participate in all PCC activities and a standby role in one or more PCCs that prohibits assignments to the PMM until at least one other PMM in the PCC assumes one of a down or unusable role.

18. The method of claim 10 wherein the step of providing comprises the step of characterizing each PMM by a primary communication network address for communicating among the PMMs and the PCC coordinator.

19. The method of claim 18 wherein the primary communication network address is the unique ID of the PMM.

20. The method of claim 1 wherein the step of providing comprises the step of characterizing each PMM by an operational status including one of a joining status when the PMM attempts to rejoin the PCC after being offline, an up status after the PCC coordinator accepts the PMM and rebalances the PCC, a leaving status when the PMM becomes unavailable to the PCC and a down status after the PMM is unavailable to the PCC.

21. The method of claim 1 wherein the step of balancing comprises the steps of:

summing the load ratings of the hosted PCC services;

calculating the load rating per address for each hosted PCC service;

creating an address list that is sorted, in decending order, by the calculated load rating per address;

summing the capacity ratings of the PMMs; and

calculating a current capacity rating of each PMM normalized to a common load unit metric.

22. The method of claim 1 wherein dynamic changes in the PCC comprises addition or deletion of services.

23. The method of claim 1 wherein dynamic changes in the PCC comprises real-time collection of load data.

24. The method of claim 1 wherein dynamic changes in the PCC comprises failure of a PMM.

25. The method of claim 1 wherein the step of rebalancing comprises the steps of:

summing the load ratings of the hosted PCC services;

calculating the load rating per address for each hosted PCC service;

creating an address list that is sorted, in decending order, by the calculated load rating per address;

summing the capacity ratings of the PMMs; and

calculating a current capacity rating of each PMM normalized to a common load unit metric.

26. The method of claim 1 wherein the step of organizing comprises the step of dynamically establishing one or more new clusters that continue to service clients if one or more PMMs loses contact with their original clusters.

27. A computer-readable medium comprising:

instructions and data written thereon, said instructions and data containing information for the practice of the method of the claim 1.

28. Electromagnetic signals traveling over a computer network comprising:

said electromagnetic signals carrying information for the practice of the method of claim 1.

29. A system for increasing the availability of services offered by a service provider to clients connected to a communications network, the clients accessing the services by issuing requests to network addresses associated with these services, the system comprising:

a plurality of processor/memory mechanisms (PMMs) cooperatively interacting to receive and service the requests on behalf of the service provider, each PMM characterized by a primary communication address and assigned at least one network address to service;

means for organizing the PMMs as one or more proxy cache clusters (PPCs) by dynamically assigning each PMM to one or more PCCs; and

means for balancing service addresses among PMMs by assigning selected service addresses to each PMM of the PCC

means for rebalancing service addresses among PMMs of the PCC in response to dynamic changes in the PCC.