Systems and Methods for Controlling the Number of Connections Established with a Server

• US 20070088826A1
• Filed: 10/31/2006
• Published: 04/19/2007
• Est. Priority Date: 07/26/2001
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Application Networking LLC (Cloud Software Group)
• Inventors: Kailash, Kailash, Raphel, Jose, Susai, Michel
• Granted Patent: US 8,799,502 B2
• Time in Patent Office: Days
• US Class Current: 709/225
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• 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
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities

Abstract

A method for maximizing server throughput while avoiding overload of a server is presented. The method involves intercepting, via an interface unit, a client request for information from the server. Next, the interface unit determines the current server performance, where the server performance is based on the number of connections opened to the server, the response time of the server and the rate at which the response time is changing. Finally, the interface unit forwards the client request to the server if the current server performance is close to an optimal performance, whereby avoiding overload of the server.

Claims

1. A method for controlling a number of transport layer connections established with a server, the method comprising the steps of:

(a) intercepting, by an interface unit, a request from a client to establish a transport layer connection with a server, the interface unit providing a pool of one or more transport layer connections to the server, the pool having at least a first transport layer connection;

(b) determining, by the interface unit, a number of transport layer connections established with the server; and

(c) opening, by the interface unit, a second transport layer connection for the pool of one or more transport layer connections to the server if the number of transport layer connections established with the server is below a maximum number of allowable connections for the server.

2. The method of claim 1, wherein step(c) comprises opening, by the interface unit, the second transport layer in response to determining the first transport layer connection to the server is not free for use by the client.

3. The method of claim 1, comprising determining, by the interface unit, the maximum number of allowable connections for the server based on one of a response time of the server or a rate at which the response time is changing.

4. The method of claim 1, comprising determining, by the interface unit, the maximum number of allowable connections for the server based on one of a number of pending requests sent to the server, an error message to the server or an overload message from the server.

5. The method of claim 1, comprising, multiplexing, by the interface unit, via the first transport layer connection one or more requests from the client to access information on the server and one or more requests by a second client to access information on the server.

6. The method of claim 1, comprising queuing, by the interface unit, the request in a buffer until one of the first transport layer connection or the second transport layer connection is free for use by the client.

7. The method of claim 1, comprising queuing, by the interface unit, the request from the client in response to determining the number of transport layer connections to the server is one of equal to or greater than the maximum number of allowable connections.

8. The method of claim 7, comprising determining, by the interface unit, a preferred client value for the request of the client, and determining a position of the request in the buffer based on the preferred client value.

9. The method of claim 8, comprising determining, by the interface unit, the preferred client value by one of a network address, a port address, a header or a cookie related to the request of the client.

10. The method of claim 1, comprising closing, by the interface unit, one transport layer connection of the pool of one or more transport layer connections to the server in response to determining the server'"'"'s performance exceeds a predetermined threshold.

11. A system for controlling a rate of establishing network connections to a server, the system comprising:

means for intercepting, by an interface unit, a request from a client to establish a transport layer connection with a server, the interface unit providing a pool of one or more transport layer connections to the server, the pool having at least a first transport layer connection;

means for determining, by the interface unit, a number of transport layer connections established with the server; and

means for opening, by the interface unit, a second transport layer connection for the pool of one or more transport layer connections to the server if the number of transport layer connections established with the server is below a maximum number of allowable connections for the server.

12. The system of claim 11, comprising means for opening, by the interface unit, the second transport layer in response to determining the first transport layer connection to the server is not free for use by the client.

13. The system of claim 11, comprising means for determining, by the interface unit, the maximum number of allowable connections for the server based on one of a response time of the server or a rate at which the response time is changing.

14. The system of claim 11, comprising means for determining, by the interface unit, the maximum number of allowable connections for the server based on one of a number of pending requests sent to the server, an error message to the server or an overload message from the server.

15. The system of claim 11, comprising, means for multiplexing, by the interface unit, via the first transport layer connection one or more requests from the client to access information on the server and one or more requests by a second client to access information on the server.

16. The system of claim 11, comprising means for queuing, by the interface unit, the request in a buffer until one of the first transport layer connection or the second transport layer connection is free for use by the client.

17. The system of claim 11, comprising means for queuing, by the interface unit, the request from the client in response to determining the number of transport layer connections to the server is one of equal to or greater than the maximum number of allowable connections.

18. The system of claim 17, comprising means for determining, by the interface unit, a preferred client value for the request of the client, and determining a position of the request in the buffer based on the preferred client value.

19. The system of claim 18, comprising means for determining, by the interface unit, the preferred client value by one of a network address, a port address, a header or a cookie related to the request of the client.

20. The system of claim 11, comprising means for closing, by the interface unit, one transport layer connection of the pool of one or more transport layer connections to the server in response to determining the server'"'"'s performance exceeds a predetermined threshold.