System and method for performing application level persistence

• US 7,831,712 B1
• Filed: 10/17/2007
• Issued: 11/09/2010
• Est. Priority Date: 07/15/1999
• Status: Expired due to Term

• 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:
  US11/874,109
• Time in Patent Office: 1,119 Days
• Field of Search: 709/217, 709/219, 709/223, 709/225, 709/226, 709/250
• US Class Current: 709/225
• 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 method for providing persistent communications between at least one client and a plurality of destination servers that serve a network domain resource, comprising:

enabling at least one of the plurality of destination servers to receive application level protocol requests from a client, the application level protocol requests being forwarded to one of the plurality of destination servers with a network transmission device;

receiving, at the one of the plurality of destination servers, a first application level protocol request from the client, the first application level protocol request comprising a request for access to the network domain resource provided by the destination server, wherein the client'"'"'s first application level protocol request is unspecific regarding the one destination server that provides access to the network domain resource;

sending, to the client, an application level protocol command to store data, the application level protocol command including information inserted by the network transmission device that indicates the one of the plurality of destination servers that received the first application level protocol request from the client; and

receiving, at the one of the plurality of destination servers, a second application level protocol request from the client;

wherein the information included with the application level protocol command is also included with the second application level protocol request and employable by the network transmission device to indicate the one of the plurality of destination servers.

2. The method of claim 1, further comprising sending, to the client, a response to each application level protocol request.

3. The method of claim 1, further comprising sending, to the client, a timestamp indicative of a time period during which the information is to be used.

4. The method of claim 1, wherein the information comprises a specification of a node address and a node port number.

5. The method of claim 1, wherein the application level protocol is the Hypertext Transfer Protocol (HTTP).

6. The method of claim 1, wherein the application level protocol command to store data is a command to create a cookie.

7. A method for providing persistent communications between at least one client and a plurality of destination servers, comprising:

enabling at least one of the plurality of destination servers to receive from a client application level protocol requests, the application level protocol requests being forwarded to at least one of the plurality of destination servers with a network transmission device;

receiving, at one of the plurality of destination servers, a first application level protocol request from the client, wherein the first application level protocol request comprises a request for access to a network domain resource served by the one of the plurality of destination servers, and wherein the client'"'"'s first application level protocol request is unspecific regarding the one destination server that provides access to the network domain resource; and

sending, to the client, with a first response to the first application level protocol request, an application level protocol command to store data, the application level protocol command including a designated space for insertion of information indicating the one of the plurality of destination servers by the network transmission device.

8. The method of claim 7, further comprising:

receiving, at the one of the plurality of destination servers, a second application level protocol request from the client; and

sending, to the client, a second response to the second application level protocol request.

9. The method of claim 7, wherein the space is sized to allow the network transmission device to rewrite the one of the plurality of destination servers particular identification data in the space and to maintain the size of the first response.

10. The method of claim 7, wherein the application level protocol command is recognizable by the network transmission device as including the space, and wherein the space is overwritable.

11. The method of claim 7, wherein the one of the plurality of destination servers maintains content relating to including the space in the application level protocol command to store data, the content being substantially the same as content maintained on at least one other of the plurality of destination servers.

12. The method of claim 7, wherein the application level protocol command is provided without information identifying any one of the plurality of destination servers.

13. The method of claim 7, wherein the application level protocol is the Hypertext Transfer Protocol (HTTP).

14. The method of claim 7, wherein the application level protocol command to store data is a command to create a cookie.

15. 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 of a plurality of servers; and

a processor for enabling actions, including;

enabling at least one of the plurality of servers to send an application level response to an application level request from a client for access to a network domain resource served by at least one of the plurality of servers, wherein the client'"'"'s application level request is unspecific regarding the at least one server that provides access to the network domain resource;

employing the device to add information within an application level protocol command to the application level response and send the application level response along with the added information to the client, wherein the added information indicates the one of the plurality of servers that responded to the application level request from the client for access to the network domain resource; and

if the added information is included with another application level request from the client, employing the added information to process the other application level request for access to the network domain resource.

16. The device of claim 15, further comprising employing the device to determine the one of the plurality of servers for responding to the other application level request based at least in part on the added information.

17. The device of claim 15, further comprising employing the device to add information by overwriting at least a portion of the application level response.

18. The device of claim 15, further comprising employing the device to add information by inserting the information in the application level response.

19. The device of claim 15, 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.

20. The device of claim 15, wherein the application level messages are operational with at least the Hypertext Transport Protocol (HTTP).

21. The device of claim 15, further comprising enabling at least one of the plurality of servers to set information included in the application level response that indicates at least one of the server and the client.

22. The device of claim 15, further comprising employing the device to set the added information to indicate at least one of the plurality of servers and the client.

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

a network interface for communicating over the network; and

a processor for enabling actions, including;

providing a request from a client to at least one of the plurality of servers to access a network domain resource, wherein persistence information is included by the device in a response to the request from one of the plurality of servers that serves the network domain resource, and wherein the persistence information indicates the server that responded to the request from the client, and wherein the client'"'"'s request is unspecific regarding the at least one server that serves access to the network domain resource;

examining the request for persistence information included in the response;

forwarding the response with the persistence information to the client; and

if a subsequent request from the client includes the persistence information that indicates the server that previously responded to the request from the client, directing the request to the indicated one of the plurality of servers.

24. The device of claim 23, further comprising including information along with the persistence information that identifies at least one of the one server and the client.

25. The device of claim 23, further comprising storing at least the persistence information in response to receiving the response from the one of the plurality of servers.

26. A computer readable storage medium, comprising executable instructions for enabling communication between at least one of a plurality of servers and at least one client in a network, the actions comprising:

enabling at least one of the plurality of destination servers to receive application level protocol requests from a client, the application level protocol requests being forwarded to one of the plurality of destination servers with a network transmission device;

receiving, at the one of the plurality of destination servers, a first application level protocol request from the client, the first application level protocol request comprising a request for access to the network domain resource provided by the destination server, and wherein the client'"'"'s first application level protocol request is unspecific regarding the at least one destination server that provides access to the network domain resource;

sending, to the client, an application level protocol command to store data, the application level protocol command including information inserted by the network transmission device that indicates the one of the plurality of destination servers that received the first application level protocol request from the client; and

receiving, at the one of the plurality of destination servers, a second application level protocol request from the client;

wherein the information included with the application level protocol command is also included with the second application level protocol request and employable by the network transmission device to indicate the one of the plurality of destination servers.

27. The computer readable storage medium of claim 26, wherein the actions further comprise sending, to the client, a response to each application level protocol request.

28. The computer readable storage medium of claim 26, wherein the actions further comprise sending, to the client, a timestamp indicative of a time period during which the information is to be used.

29. The computer readable storage medium of claim 26, wherein the information comprises a specification of a node address and a node port number.

30. The computer readable storage medium of claim 26, wherein the application level protocol is the Hypertext Transfer Protocol (HTTP).

31. The computer readable storage medium of claim 26, wherein the application level protocol command to store data is a command to create a cookie.

32. A system for providing persistent communication over a network for a network domain resource, comprising:

a plurality of destination servers; and

a network device, including;

at least one memory for storing instructions; and

at least one processor for executing the instructions, the executed instructions enabling actions, including;

enabling at least one of the plurality of destination servers to receive application level protocol requests from a client, the application level protocol requests being forwarded to one of the plurality of destination servers with a network transmission device;

receiving, at the one of the plurality of destination servers, a first application level protocol request from the client, the first application level protocol request comprising a request for access to the network domain resource provided by the destination server, and wherein the client'"'"'s first application level protocol rawest is unspecific regarding the at least one destination server that provides access to the network domain resource;

sending, to the client, an application level protocol command to store data, the application level protocol command including information inserted by the network transmission device that indicates the one of the plurality of destination servers that received the first application level protocol request from the client; and

receiving, at the one of the plurality of destination servers, a second application level protocol request from the client;

wherein the information included with the application level protocol command is also included with the second application level protocol request and employable by the network transmission device to indicate the one of the plurality of destination servers.

33. The system of claim 32, wherein the actions further comprise sending, to the client, a response to each application level protocol request.

34. The system of claim 32, wherein the actions further comprise sending, to the client, a timestamp indicative of a time period during which the information is to be used.

35. The system of claim 32, wherein the information comprises a specification of a node address and a node port number.

36. The system of claim 32, wherein the application level protocol is the Hypertext Transfer Protocol (HTTP).

37. The system of claim 32, wherein the application level protocol command to store data is a command to create a cookie.

38. A computer readable storage medium, comprising executable instructions for performing actions for providing persistent communications between at least one client and a plurality of destination servers, the actions comprising:

enabling at least one of the plurality of destination servers to receive from a client application level protocol requests, the application level protocol requests being forwarded to at least one of the plurality of destination servers with a network transmission device;

receiving, at one of the plurality of destination servers, a first application level protocol request from the client, wherein the first application level protocol request comprises a request for access to a network domain resource served by the one of the plurality of destination servers, and wherein the client'"'"'s first application level protocol request is unspecific regarding the at least one destination server that provides access to the network domain resource; and

sending, to the client, with a first response to the first application level protocol request, an application level protocol command to store data, the application level protocol command including a designated space for insertion of information indicating the one of the plurality of destination servers by the network transmission device.

39. The computer readable storage medium of claim 38, wherein the actions further comprise:

receiving, at the one of the plurality of destination servers, a second application level protocol request from the client; and

sending, to the client, a second response to the second application level protocol request.

40. The computer readable storage medium of claim 38, wherein the space is sized to allow the network transmission device to rewrite the one of the plurality of destination servers particular identification data in the space and to maintain the size of the first response.

41. The computer readable storage medium of claim 38, wherein the application level protocol command is recognizable by the network transmission device as including the space, and wherein the space is overwritable.

42. The computer readable storage medium of claim 38, wherein the one of the plurality of destination servers maintains content relating to including the space in the application level protocol command to store data, the content being substantially the same as content maintained on at least one other of the plurality of destination servers.

43. The computer readable storage medium of claim 38, wherein the application level protocol command is provided without information identifying any one of the plurality of destination servers.

44. The computer readable storage medium of claim 38, wherein the application level protocol is the Hypertext Transfer Protocol (HTTP).

45. The computer readable storage medium of claim 38, wherein the application level protocol command to store data is a command to create a cookie.

46. A system for providing persistent communication over a network for a network domain resource, comprising:

a plurality of destination servers; and

a network device, including;

at least one memory for storing instructions; and

at least one processor for executing the instructions, the executed instructions enabling actions, including;

enabling at least one of the plurality of destination servers to receive from a client application level protocol requests, the application level protocol requests being forwarded to at least one of the plurality of destination servers with the network transmission device;

receiving, at one of the plurality of destination servers, a first application level protocol request from the client, wherein the first application level protocol request comprises a request for access to a network domain resource served by the one of the plurality of destination servers, and wherein the client'"'"'s first application level protocol request is unspecific regarding the at least one destination server that provides access to the network domain resource; and

sending, to the client, with a first response to the first application level protocol request, an application level protocol command to store data, the application level protocol command including a designated space for insertion of information indicating the one of the plurality of destination servers by the network transmission device.

47. The system of claim 46, wherein the actions further comprise:

receiving, at the one of the plurality of destination servers, a second application level protocol request from the client and

sending, to the client, a second response to the second application level protocol request.

48. The system of claim 46, wherein the space is sized to allow the network transmission device to rewrite the one of the plurality of destination servers particular identification data in the space and to maintain the size of the first response.

49. The system of claim 46, wherein the application level protocol command is recognizable by the network transmission device as including the space, and wherein the space is overwritable.

50. The system of claim 46, wherein the one of the plurality of destination servers maintains content relating to including the space in the application level protocol command to store data, the content being substantially the same as content maintained on at least one other of the plurality of destination servers.

51. The system of claim 46, wherein the application level protocol command is provided without information identifying any one of the plurality of destination servers.

52. The system of claim 46, wherein the application level protocol is the Hypertext Transfer Protocol (HTTP).

53. The system of claim 46, wherein the application level protocol command to store data is a command to create a cookie.