Enabling application level persistence between a server and another resource over a network

• US 6,970,933 B1
• Filed: 10/28/2002
• Issued: 11/29/2005
• 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:
  US10/284,035
• Time in Patent Office: 1,128 Days
• Field of Search: 709/203, 709/217, 709/219, 709/223, 709/227, 709/228, 709/229, 719/328, 719/329
• US Class Current: 709/229
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• 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
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data

Abstract

A method and system for inserting and examining Cookies in the data streams of HTTP connections for the purpose of persistently directing HTTP connections to the same destination. The invention enables a network device to direct 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 associative 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 responses prior to processing by the destination.

Claims

1. A system for processing remote client requests on a computer network, comprising:

an intermediate network device that communicates with a remote client and forwards remote client requests;

a plurality of servers, including a first server comprising a memory for storing logical instructions and a processor for executing the logical instructions, the execution of the logical instructions causing functions to be performed including;

receiving, from the remote client, a first application level request for a first resource;

generating a response, the response providing access to the first resource;

inserting, in the response, an application level protocol command to store persistence information for providing a mechanism allowing the remote client to send a second application level request to the server; and

sending the response to the remote client through the intermediate network device; and

wherein the intermediate network device comprises a memory for storing logical instructions and a processor for executing the logical instructions, the execution of the logical instructions causing functions to be performed including;

receiving, from the remote client, a second application level request for a second resource, the second application level request comprising the persistence information;

identifying the first server as a target server, based on the persistence information; and

forwarding the second application level request to the first server.

2. The system of claim 1, wherein the execution of the server logical instructions causes insertion of an instruction to the remote client that instructs the remote client to insert the persistence information in an HTTP header in the second application level resource request.

3. A system for processing remote client requests on a computer network, comprising:

an intermediate network device that communicates with a remote client and forwards remote client requests;

a plurality of servers, including a first server comprising a server memory for storing server logical instructions and a server processor for executing the server logical instructions, the execution of the server logical instructions causing functions to be performed including;

receiving, from the remote client, a first application level request for a first resource;

generating a response, the response providing access to the first resource;

inserting, in the response, a space sized to allow the insertion of persistence information for providing a mechanism allowing the remote client to send a second application level request to the server; and

sending the response to the remote client through the intermediate network device; and

wherein the intermediate network device (IND) comprises an IND memory for storing IND logical instructions and an IND processor for executing the IND logical instructions, the execution of the IND logical instructions causing functions to be performed including;

receiving, from the first server, the response to the remote client request;

writing, into said space, the persistence information;

receiving, from the remote client, a second application level request for a second resource, the second application level request comprising the persistence information;

identifying the first server as a target server, based on the persistence information; and

forwarding the second application level request to the first server.

4. The system of claim 3, wherein the execution of the IND logical instructions causes writing, into said space, an instruction to the remote client that instructs the remote client to insert the persistence information in an HTTP header in the second application level resource request.

5. 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 provide an application level response in which the server inserts a cookie, in response to an application level request from a client;

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

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

if the cookie that includes the identity of the server 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 server to the client.

6. The device of claim 5, 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.

7. The device of claim 5, wherein each application level request and each application level response is operational with at least the Hypertext Transport Protocol (HTTP).

8. The device of claim 5, further comprising employing the device to rewrite at least a portion of the cookie with information.

9. The device of claim 5, further comprising enabling the server to set information included in the cookie to indicate at least one of the server and the client.

10. The device of claim 5, further comprising employing the device to set information included in the cookie to indicate at least one of the server and the client.

11. The device of claim 5, wherein the device stores the identity of the server and the mapping in response to receiving the application level response from the server.

12. The device of claim 5, wherein the cookie includes a key.

13. 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 provide an application level response in which the server inserts a cookie, in response to an application level request from a client;

employing the device to store information that corresponds to other information that is included in the cookie and provide the application level response that includes the cookie to the client, wherein the other information included in the cookie indicates the server that provided the application level response to the client; and

based on a correspondence between the stored information and the other information included in the cookie that is subsequently included in another application level request from the client, employing the device to direct the other application level request to the server.

14. The device of claim 13, further comprising employing the device to set at least one identification in the cookie, wherein the set identification indicates the server.

15. The device of claim 13, 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.

16. The device of claim 13, wherein the application level request and response are operational with at least the Hypertext Transport Protocol (HTTP).

17. The device of claim 13, wherein the device stores the information in response to receiving the application level response from the server.

18. The device of claim 13, wherein the cookie includes a key.