Method and system for enabling persistent access to virtual servers by an LDNS server

• US 7,707,289 B1
• Filed: 04/20/2006
• Issued: 04/27/2010
• Est. Priority Date: 01/31/2000
• Status: Active Grant

• Current Assignee: F5 Networks, Inc. (F5 Incorporated)
• Original Assignee: F5 Networks, Inc. (F5 Incorporated)
• Inventors: Thornewell, Peter M., Skene, Bryan D.
• Primary Examiner(s): BOUTAH, ALINA A
• Application Number:
  US11/379,557
• Time in Patent Office: 1,468 Days
• Field of Search: 709217-219, 709226-229, 709/232, 718/105
• US Class Current: 709/226
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Disclosed are methods and systems for providing persistence across multiple requests in a WAN load-balanced environment. More than one load balancing system may be used to provide persistence while load balancing. One method and system disclosed provides persistence by using modulus arithmetic to load balance requests. Another method and system disclosed provides persistence using topology information contained in the request. Another method and system disclosed provides persistence by storing connection information to refer a timely continuation request of a prior request to the same server the prior request was referred to. When more than one load balancing system is used with this method, the load balancing systems periodically exchange the stored connection information so that each load balancing system may provide persistence to repeat requests.

Claims

1. A server for accessing a resource on a network, comprising:

a computer-readable storage device that stores instructions which when executed on the server enable actions including;

receiving a request for the resource from a connection that is associated with a client;

enabling selection of a method to select one of a plurality of server array controllers to handle each request from the connection to the resource;

enabling selection of a method for load balancing each request from the connection, wherein the selected load balancing method employs modulus arithmetic to select a virtual server managed by the selected server array controller;

storing connection data for the connection, including at least a first data that identifies the selected virtual server and a second data that identifies the selected server array controller; and

referring each request that is associated with the connection to the selected server array controller based on the stored connection data including at least the first data and the second data, until another method is selected for load balancing each request from the connection, wherein the selected server array controller associates the client'"'"'s connection with the requested resource and manages one or more virtual servers.

2. The server of claim 1, wherein if the selected virtual server is determined to be down, the selected load balancing method performs further actions, including:

marking the down selected virtual server as unavailable;

decrementing a total amount of available virtual servers by 1 to create a value for N; and

employing the value for N to select another virtual server array.

3. The server of claim 1, wherein the selected server array controller associates the requestor with a virtual server that includes the resource, and wherein the virtual server is managed by the selected server array controller.

4. The server of claim 1, wherein the request includes an IP address associated with the requestor, another IP address associated with the selected server array controller, and a time stamp.

5. The server of claim 1, wherein the server is operable as a Local Domain Name Server (LDNS).

6. The server of claim 1, wherein the server is operable as an Extended Domain Name Server (EDNS).

7. A method for accessing a resource on a network, comprising:

receiving a request for the resource from a connection that is associated with a requestor;

enabling selection of a method to select one of a plurality of server array controllers to handle each request from the connection to the resource;

enabling selection of a method for load balancing each request from the connection, wherein the selected load balancing method employs modulus arithmetic to select a virtual server managed by the selected server array controller;

storing connection data for the connection, including at least a first data that identifies the selected virtual server and a second data that identifies the selected server array controller; and

referring each request that is associated with the connection to the selected server array controller based on the stored connection data including at least the first data and the second data, until another method is selected for load balancing each request from the connection, wherein the selected server array controller associates the requestor'"'"'s connection with the requested resource and manages one or more virtual servers.

8. The method of claim 7, wherein if the selected virtual server is determined to be down, the selected load balancing method performs further actions, including:

marking the down selected virtual server as unavailable;

decrementing a total amount of available virtual servers by 1 to create a value for N; and

employing the value for N to select another virtual server array.

9. The method of claim 7, wherein the selected server array controller associates the requestor with a virtual server that includes the resource, and wherein the virtual server is managed by the selected server array controller.

10. The method of claim 7, wherein the request includes an IP address associated with the requestor, another IP address associated with the selected server array controller, and a time stamp.

11. A computer readable media that stores executable data for enabling actions that access a resource on a network, the actions comprising:

receiving a request for the resource from a connection that is associated with a requestor;

enabling selection of a method to select one of a plurality of server array controllers to handle each request from the connection to the resource;

enabling selection of a method for load balancing each request from the connection, wherein the selected load balancing method employs modulus arithmetic to select a virtual server managed by the selected server array controller;

storing connection data for the connection, including at least a first data that identifies the selected virtual server and a second data that identifies the selected server array controller; and

referring each request that is associated with the connection to the selected server array controller based on the stored connection data including at least the first data and the second data, until another method is selected for load balancing each request from the connection, wherein the selected server array controller associates the requestor'"'"'s connection with the requested resource and manages one or more virtual servers.

12. The media of claim 11, wherein if the selected virtual server is determined to be down, the selected load balancing method performs further actions, including:

marking the down selected virtual server as unavailable;

decrementing a total amount of available virtual servers by 1 to create a value for N; and

employing the value for N to select another virtual server array.

13. The media of claim 11, wherein the selected server array controller associates the requestor with a virtual server that includes the resource, and wherein the virtual server is managed by the selected server array controller.

14. The media of claim 11, wherein the request includes an IP address associated with the requestor, another IP address associated with the selected server array controller, and a time stamp.

15. A system for enabling access to a resource on a network, comprising:

a client machine that is coupled to the network; and

a server that includes a computer-readable storage device that stores instructions which when executed perform actions including;

receiving a request for the resource from a connection that is associated with the client;

enabling selection of a method to select one of a plurality of server array controllers to handle each request from the connection to the resource;

enabling selection of a method for load balancing each request from the connection, wherein the selected load balancing method employs modulus arithmetic to select a virtual server managed by the selected server array controller;

storing connection data for the connection, including at least a first data that identifies the selected virtual server and a second data that identifies the selected server array controller; and

referring each request that is associated with the connection to the selected server array controller based on the stored connection data including at least the first data and the second data, until another method is selected for load balancing each request from the connection, wherein the selected server array controller associates the client'"'"'s connection with the requested resource and manages one or more virtual servers.

16. The system of claim 15, wherein if the selected virtual server is determined to be down, the selected load balancing method performs further actions, including:

marking the down selected virtual server as unavailable;

decrementing a total amount of available virtual servers by 1 to create a value for N; and

employing the value for N to select another virtual server array.

17. The system of claim 15, wherein the selected server array controller associates the client with a virtual server that includes the resource, and wherein the virtual server is managed by the selected server array controller.

18. The system of claim 15, wherein the request includes an IP address associated with the client, another IP address associated with the selected server array controller, and a time stamp.

19. The system of claim 15, wherein the server is operable as a Local Domain Name Server (LDNS).

20. The system of claim 15, wherein the server is operable as an Extended Domain Name Server (EDNS).