Connection management system and method

• US 7,007,092 B2
• Filed: 10/05/2001
• Issued: 02/28/2006
• Est. Priority Date: 10/05/2000
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Peiffer, Christopher
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): Dalencourt, Yves
• Application Number:
  US09/972,691
• Publication Number:
  US 20020042828A1
• Time in Patent Office: 1,607 Days
• Field of Search: 709/203, 709/205, 709/217, 709/223, 709/224, 709/227, 709/229, 709/237, 707/7, 702/186
• US Class Current: 709/227
• 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 67/1008 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 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y10S 707/99937 Sorting

Abstract

A system and method for managing connections between a server and a plurality of clients at a network connection management device is provided. The method comprises maintaining at least one connection to the server, receiving requests from the clients, transmitting the requests to the server, receiving responses to the requests from the server, and monitoring a server response time for a selected request sent to the server, the server response time for the selected request being the time elapsed between transmitting the selected request to the server and receiving a corresponding response from the server. The method may also include basing the number of connections.

Claims

1. A method of managing connections between a server and a plurality of clients at a connection management device, the connection management device being interposed between the server and the plurality of clients on a computer network, the method comprising:

maintaining one or more persistent connections to the server;

receiving requests from the clients;

transmitting the requests to the server;

receiving responses to the requests from the server;

monitoring a server response time for a selected request sent to the server, the server response time for the selected request being the time elapsed between transmitting the selected request to the server and receiving a corresponding response from the server; and

changing with the connection management device the number of persistent connections from the connection management device to the server based on the monitored server response time.

2. The method of claim 1, wherein changing with the connection management device the number of connections comprises closing with the connection management device one or more of the connections when the server response time is below a first predetermined threshold.

3. The method of claim 1, further comprising seeking a selected connection with no pending requests before transmitting a received request to the server via the selected connection.

4. The method of claim 3, further comprising opening a new connection for transmission of the received request if no connection with no pending request is found.

5. The method of claim 1, wherein monitoring the server response time includes monitoring a performance indicator that is correlated to the server response time.

6. The method of claim 5, the performance indicator having a value, wherein changing with the connection management device the number of connections comprises changing the number of connections to the server if the value of the performance indicator falls outside a determined range of values.

7. The method of claim 6, further comprising continuously updating the determined range of values by periodically correlating the server response time to the performance indicator.

8. The method of claim 5, wherein the performance indicator is selected from the group consisting of a rate of formation of new client connections to the connection management device, a rate of client requests received, a type of request received, a client type, a client bandwidth, a resource URL, and a resource type requested.

9. A method of optimizing communication between a plurality of clients and a server at a connection management device, the connection management device being configured to connect to the clients and to the server to facilitate resource transfer between the clients and the server, the method comprising:

maintaining a plurality of connections to the server;

receiving a request from a selected client;

examining the connections to the server to identify a selected connection with no pending requests;

sending the request to the server on the selected connection;

monitoring a server response time; and

decreasing the connections when the monitored server response time falls below a threshold.

10. The method of claim 9, further comprising opening a new connection to the server and sending the request to the server on the new connection if a connection with no pending requests cannot be identified.

11. The method of claim 9, wherein the connections are persistent connections and a server response time elapses between sending the request to the server and receiving a corresponding response from the server, further comprising monitoring the server response time and changing the number of persistent connections to the server if the server response time falls outside of a predetermined range of times defined at least in part by the threshold.

12. The method of claim 11, wherein decreasing the connections comprises closing one or more of the connections if the server response time is faster than the predetermined range of times.

13. The method of claim 11, wherein a connection is opened if the server response time is slower than the predetermined range of times.

14. The method of claim 9, wherein a server response time elapses between sending the request to the server and receiving a corresponding response from the server, further comprising continuously monitoring a performance indicator correlated to the server response time.

15. The method of claim 14, the performance indicator having a value, further comprising changing the number of connections to the server if the value of the performance indicator falls outside a desired value range.

16. The method of claim 15, wherein the performance indicator is selected from the group consisting of a rate of formation of new client connections to the connection management device, a rate of client requests received, a type of request received, a client type, a client bandwidth, a resource URL, and a resource type requested.

17. The method of claim 15, further comprising continuously updating the desired value range by periodically correlating the server response time to selected values of the performance indicator.

18. The method of claim 17, wherein periodically correlating the server response time to selected values of the performance indicator includes calculating a historical average of server response times for selected values of the performance indicator.

19. The method of claim 9, the connection management device being configured to receive a plurality of requests from the clients and forward the plurality of requests to the server, wherein sending the request to the server includes storing information regarding the request to help identify a corresponding response from the server.

20. A connection management device configured to manage connections between at least one client and a server, the connection management device including a controller having a processor and volatile memory, a network interface configured to interface the connection management device to the computer network, and non-volatile memory, the non-volatile memory containing a communications program executable by the controller to:

maintain a number of connections to the server;

receive requests from the clients;

transmit the requests to the server;

receive responses to the requests from the server;

monitor a server response time for a selected request sent to the server, the server response time for the selected request being the time elapsed between transmitting the selected request to the server and receiving a corresponding response from the server; and

decrease the number of connections to the server when the server response time is shorter than a predetermined range of response times.

21. The connection management device of claim 20, wherein the communications program is executable by the controller to periodically monitor a plurality of server response times for a plurality of requests.

22. The connection management device of claim 20, wherein the communications program is executable by the controller to increase the number of connections to the server when a selected server response time is longer than a predetermined range of response times.

23. The connection management device of claim 22, wherein the communications program is executable by the controller to correlate a performance indicator to the server response times.

24. The connection management device of claim 23, the performance indicator having a value, wherein the communications program is executable by the controller to base the number of connections to the server upon the value of the performance indicator.

25. The method of claim 23, wherein the performance indicator is selected from the group consisting of a rate of formation of new client connections to the connection management device, a rate of client requests received, a type of request received, a client type, a client bandwidth, a resource URL, and a type of resource requested.

26. The method of claim 23, wherein the communications program is executable by the controller to continuously update the correlation of the performance indicator to the server response times.

27. A system configured to be connected to a computer network for providing a world wide web resource to a client over the computer network, the system comprising:

a server configured to store the web resource and to respond to client requests for the web resource by serving the web resource to the client; and

a connection management device connected to the server and disposed on the network between the client and the server, the connection management device being configured to maintain a number of persistent connections to the server, to receive requests from the client, to forward the requests to the server, to receive responses to the requests from the server, to monitor an elapsed server response time between forwarding a selected request to the server and receiving a corresponding response from the server, and to decrease the number of persistent connections to the server based upon the server response time.

28. A storage medium having stored thereon instructions that, when executed by a computer connection management device disposed on a computer network between a server and a client, result in the computer connection management device having the capability of facilitate resource transfer between the client and the server by performing the steps of:

receiving a request from the client;

transmitting the request to the server;

receiving a response to the request from the server;

monitoring a server response time, the server response time being the time elapsed between transmitting the request and receiving the response;

selecting a number of connections to maintain to the server based upon the server response time; and

increasing or decreasing a current number of open connections to the server to achieve the selected number of connections.