System and method for performing application level persistence

• US 7,346,695 B1
• Filed: 10/26/2005
• Issued: 03/18/2008
• Est. Priority Date: 10/28/2002
• Status: Expired due to Fees

• Current Assignee: F5 Networks, Inc. (F5 Incorporated)
• Original Assignee: F5 Networks, Inc. (F5 Incorporated)
• Inventors: Masters, Richard R.
• Primary Examiner(s): VU, VIET DUY
• Application Number:
  US11/260,651
• Time in Patent Office: 874 Days
• Field of Search: 709/217, 709/219, 709/223, 709/226, 709/227, 709/229, 709/250, 719/328, 719/329
• US Class Current: 709/228
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/142 Managing session states for stateless protocols; Signalling session states; State transitions; Keeping-state mechanisms

Abstract

A method and apparatus for inserting and examining Cookies in the data streams of HTTP connections for the purpose of persistently directing HTTP connections to the same destination. A network device directs subsequent HTTP connections from the same client to the same server (destination) for accessing the requested resources. There are four modes for employing the Cookie to persistently direct HTTP connections. The associated mode inserts a Cookie that uniquely identifies the client into an HTTP response. The passive mode inserts Cookie information that uniquely identifies a previously selected destination into an HTTP response. In the rewrite mode, a network device manages the destination information that is rewritten over blank Cookie information generated by the destination producing the HTTP response. The insert mode inserts and removes Cookie information in the data packets for HTTP requests and response prior to processing by the destination.

Claims

1. A server for enabling persistent communication with at least one client over a network, the server performing actions, comprising:

in response to receiving an application level protocol request for a resource from the client, enabling the server to communicate an application level protocol command to the client, wherein the server includes information in the command for identifying the client;

providing the application level protocol command to a network transmission device employs information for identifying the client included with the application level protocol command to map communication between the client and the server and communicate the command to the client;

enabling the server to include the information for identifying the client in each subsequent application level protocol command communicated in response to each subsequent application level protocol request for the resource from the client; and

enabling a network transmission device to provide each subsequent application level command from the server to the client based at least in part on information for identifying the client that is included with each subsequent application level protocol command.

2. The server of claim 1, wherein the network transmission device removes the information for identifying the client prior to providing each application level protocol command to the client.

3. The server of claim 1, wherein the network transmission device employs a timestamp in the mapping of communication between the client and the server, and wherein an unexpired timestamp mapping between the client and the server enables the network transmission device to automatically communicate each application level protocol request from the client to the server.

4. The server of claim 1, wherein the information for identifying the client is included in an HTTP cookie.

5. The server of claim 1, wherein the network transmission device is a controller for managing communication with a plurality of servers.

6. A server for enabling persistent communication with at least one client over a network, the server performing actions, comprising:

in response to receiving an application level protocol request from a client, enabling the server to communicate an application level protocol command to the client, wherein the application level protocol command includes information for identifying the server that received the application level protocol request from the client;

enabling the client to include the information identifying the server in each subsequent application level protocol request; and

enabling a network transmission device to provide each subsequent application level protocol request from the client to the server based at least in part on information for identifying the server that is included with each subsequent application level protocol request.

7. The server of claim 6, wherein the information for identifying the server is included in an HTTP cookie.

8. The server of claim 6, wherein the network transmission device is a controller for managing communications with a plurality of servers.

9. A server for enabling persistent communication with at least one client over a network, the server performing actions, comprising:

in response to receiving an application level protocol request from the client, enabling the server to communicate an application level protocol command to the client, wherein the application level protocol command includes at least a designated portion for information to be rewritten to identify the server;

providing the application level protocol command to a network transmission device for communicating to the client, wherein the network transmission device is enabled to rewrite the portion of the application level protocol command with information that identifies the server;

enabling the client to include the information for identifying the server in each subsequent application level protocol request; and

enabling the network transmission device to provide each subsequent application level request from the client to the server based at least in part on information for identifying the server that is included with each subsequent application level protocol request.

10. The server of claim 9, wherein the portion of the application level protocol command maintains its size after the information identifying the server is rewritten.

11. The server of claim 9, wherein the information for identifying the server is included in an HTTP cookie.

12. The server of claim 9, wherein the network transmission device is a controller for managing communications with a plurality of servers.

13. A server for enabling persistent communication with at least one client over a network, the server performing actions, comprising:

in response to receiving an application level protocol request from the client, enabling the server to communicate an application level protocol command to the client;

providing the application level protocol command to a network transmission device for communicating to the client, wherein the network transmission device inserts information for identifying the server into the application level protocol command prior to communicating the command to the client, wherein the information indicates the server that received the application level protocol request from the client;

enabling the client to include the information for identifying the server in each subsequent application level protocol request; and

enabling a network transmission device to provide each subsequent application level request from the client to the server based at least in part on information for identifying the server that is included with each subsequent application level protocol request, wherein the network transmission device removes the information for identifying the server prior to providing each application level protocol request to the server.

14. The server of claim 13, wherein the information for identifying the server is included in an HTTP cookie.

15. The server of claim 13, wherein the network transmission device is a controller for managing communications with a plurality of servers.

16. A device for enabling communication between at least one of a plurality of servers and at least one client in a network, comprising:

a network interface for communicating application level messages between at least one client and at least one server; and

a processor for enabling actions, including;

enabling a server to insert a cookie in an application level response to an application level request from a client;

employing the device to store an identity of the client and a mapping between the client and the server;

employing the device to send to the client the application level response along with the cookie that includes the identity of the client; and

if the cookie that includes the identity of the client is included with another application level request from the client, employing the device to direct the other request to the server indicated by the stored mapping of the client to the server.

17. The device of claim 16, wherein the device is operational as at least one of a router, a load balancer, a switch, a server array controller, a server, and an intermediate network device.

18. The device of claim 16, wherein the application level messages are operational with at least the Hypertext Transport Protocol (HTTP).

19. The device of claim 16, further comprising employing the device to rewrite at least a portion of the cookie to include information.

20. The device of claim 16, further comprising enabling the server to set information included in the cookie to indicate at least one of the server and the client.

21. The device of claim 16, further comprising employing the device to set information included in the cookie to indicate at least one of the server and the client.

22. The device of claim 16, wherein the device stores the identity of the client and the mapping in response to receiving the application level response from the server.

23. The device of claim 16, wherein the cookie includes a key.

24. The device of claim 16, further comprising enabling the server to set at least one identification in the cookie, wherein the set identification indicates at least one of the server and the client.