System and method for maintaining statefulness during client-server interactions

• US 8,346,848 B2
• Filed: 08/16/2002
• Issued: 01/01/2013
• Est. Priority Date: 08/16/2001
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Peiffer, Christopher, L'Heureux, Israel
• Primary Examiner(s): GOODCHILD, WILLIAM J
• Application Number:
  US10/222,051
• Publication Number:
  US 20030037108A1
• Time in Patent Office: 3,791 Days
• Field of Search: 709/203, 709/200, 709/228, 709/238, 709/250, 726/4
• US Class Current: 709/203
• 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 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1014 based on the content of a request
• 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 67/2871 Implementation details of single intermediate entities
• CPC Class Codes: H04L 67/2895 Intermediate processing functionally located close to the data provider application, e.g. reverse proxies
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• 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 67/561 Adding application-functional data or data for application control, e.g. adding metadata
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

The present invention provides systems and methods for maintaining stateful interactions between clients and servers. Furthermore, the invention provides systems and methods for maintaining stateful interactions between clients and load balancers. In one embodiment, the present invention provides systems and methods for maintaining statefulness without the need for the server to query and/or store information on the client.

Claims

1. A system for maintaining statefulness through a series of transactions between a client and a server over a computer network without having the server query and/or store any information on the client, the system comprising:

an appliance situated between the client and the server on the computer network, the appliance being configured to;

intercept a response containing a web resource being sent to the client from the server in response to a request from the client, wherein the web resource includes a server session identifier assigned by the server;

remove the server session identifier and modify the web resource to include a client session identifier that is different from the server session identifier and assigned by the appliance such that any subsequent requests originating via the modified web resource can be identified by the appliance as originating from the same client to which the intercepted response was directed;

send the modified web resource to the client;

receive subsequent requests from the client that include the client session identifier;

determine that the client session identifier assigned by the appliance is associated with the server session identifier assigned by the server to identify the subsequent requests as originating from the modified web resource;

modify the subsequent requests originating from the modified web resource to include the server session identifier that is recognizable by the server; and

forward the subsequent requests to the server.

2. The system of claim 1 wherein the computer network includes a plurality of servers and the appliance is further adapted to select which of the plurality of servers to send the request to based on the session identifier.

3. The system of claim 1 wherein the appliance assigns the client session identifier and the server session identifier.

4. The system of claim 1 wherein the client session identifier is added to one or more Uniform Resource Locator (URLs) in the resource.

5. The system of claim 1 wherein the client session identifier is added to a content location header for the resource.

6. The system of claim 1 wherein the server assigns the server session identifier by setting a cookie on the appliance.

7. A method for directing client requests to an appropriate server in a computer network including a plurality of servers, the method comprising:

intercepting a requested web resource sent from the a first server to a client before the resource reaches the client, wherein the web resource includes a server session identifier;

generating with the intermediate device a client session identifier that uniquely identifies the client, wherein the client session identifier is different from the server session identifier;

modifying the requested web resource with the intermediate device to remove the server session identifier and to include the client session identifier such that any subsequent requests originating by the client from the modified resource can be identified by the intermediate device as originating from the same client to which the intercepted response was directed;

sending the modified web resource from the intermediate device to the client;

receiving with the intermediate device a new request for a second web resource from the remote client;

determining that the new request originated from the modified web resource by determining with the intermediate device whether the client session identifier that maps to the server session identifier is present in the new request; and

when the client session identifier is present in the new request, modifying the new request with the intermediate device to include the server session identifier and sending the new request in modified form to the first server.

8. The method of claim 7 wherein the computer network includes a plurality of servers, the method further comprising selecting which of the servers to send the second request to based on the session identifier.

9. The method of claim 7 further comprising adjusting the content of the second requested web resource based on the session identifier.

10. The method of claim 7 wherein modifying the requested web resource includes modifying all Uniform Resource Locators (URLs) in the resource to include the client session identifier.

11. The method of claim 7 wherein modifying the requested web resource includes modifying a content location header for the resource to include the client session identifier.