Method and system for reducing memory used for idle connections

• US 8,645,556 B1
• Filed: 04/08/2003
• Issued: 02/04/2014
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: F5 Networks, Inc. (F5 Incorporated)
• Original Assignee: F5 Networks, Inc. (F5 Incorporated)
• Inventors: Masters, Richard Roderick
• Primary Examiner(s): Najjar, Saleh
• Assistant Examiner(s): Plotkin, Jason
• Application Number:
  US10/409,951
• Time in Patent Office: 3,955 Days
• Field of Search: 709/230, 709227-229, 709201-203, 709223-224, 703/21
• US Class Current: 709/230
• 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 67/1006 with static server selection, e.g. the same server being selected for a specific client
• 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 67/1014 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

Abstract

A method and system for reducing memory required to maintain connection states in a traffic manager. A network device receives a message from a client in which at least a portion of the message is to be forward to a first server. If the network device is maintaining information for facilitating a first connection with a second server, the network device maintains a subset of the information for use in restoring the first connection and frees memory associated with information that is not needed for restoring the first connection. The network device then employs other previously stored information to restore the state of a second connection to the first server. The network device then sends at least a portion of the message to the first server using the second connection.

Claims

1. A method of forwarding messages over a network, comprising:

creating a first TCP/IP connection between a network device and a client;

creating a second TCP/IP connection between the network device and a server;

storing essential TCP/IP connection information associated with each of the first TCP/IP connection and the second TCP/IP connection in a connection object;

allocating a memory for, and storing therein, non-essential TCP/IP connection information in the connection object;

forwarding a first message between the client and the server using the connection object;

saving on a computer storage medium accessible by the network device the essential TCP/IP connection information that was stored in the connection object and freeing the memory allocated in the connection object for non-essential TCP/IP connection information;

receiving, at the network device, a second message from the client;

copying the saved essential TCP/IP connection information into a new connection object; and

forwarding the second message to the server using the new connection object.

2. The method of claim 1, further comprising:

receiving a third message from the client to be forwarded to the server;

in response to receiving the third message, copying the saved essential TCP/IP connection information into another new connection object; and

if the second TCP/IP connection is unavailable, creating and employing a new TCP/IP connection between the network device and the server to forward the second message to the server.

3. The method of claim 1, wherein the network device is a traffic manager.

4. The method of claim 3, wherein the traffic manager selects the server to which to forward at least a portion of the first message.

5. The method of claim 1, wherein the essential TCP/IP connection information associated with the first TCP/IP connection includes an IP address, port number, and packet sequence number associated with the client and wherein the essential TCP/IP connection information associated with the second TCP/IP connection includes an IP address, port number, and packet sequence number associated with the server.

6. The method of claim 1, wherein saving the stored essential TCP/IP connection information includes copying the stored essential TCP/IP connection information into a computer storage medium.

7. The method of claim 1, wherein the saved essential TCP/IP connection information resides in a particular portion of random access memory (RAM) and wherein saving the essential TCP/IP connection information includes keeping the essential TCP/IP connection information in the particular portion of RAM.

8. The method of claim 1, wherein saving the essential TCP/IP connection information that was stored in the connection object and freeing the memory allocated for non-essential TCP/IP connection information in the connection object is performed in response to determining that the second TCP/IP connection is idle.

9. The method of claim 1, wherein saving the essential TCP/IP connection information that was stored in the connection object and freeing the memory allocated for non-essential TCP/IP connection information in the connection object is performed by copying the stored essential connection information to another object and freeing the connection object.

10. The method of claim 1, wherein the non-essential TCP/IP connection information includes a buffer.

11. A non-transitory computer-readable storage medium having computer-executable instructions for forwarding network messages, comprising:

creating a first TCP/IP connection between a network device and a client;

creating a second TCP/IP connection between the network device and a server;

storing essential TCP/IP connection information associated with each of the first TCP/IP connection and the second TCP/IP connection in a connection object;

allocating a memory for, and storing therein, non-essential TCP/IP connection information in the connection object;

forwarding a first message between the client and the server using the connection object;

determining if the second TCP/IP connection is not in use;

if the second TCP/IP connection is determined to be not in use, saving on a computer storage medium accessible by the network device the essential TCP/IP connection information that was stored in the connection object and freeing the memory allocated in the connection object for non-essential TCP/IP connection information;

receiving, at the network device, a second message from the client;

copying the saved essential TCP/IP connection information into a new connection object; and

forwarding the second message to the server using the new connection object.

12. The non-transitory computer-readable storage medium of claim 11, further comprising opening another connection between the network device and the server if a client is not authorized to employ the second TCP/IP connection.

13. The non-transitory computer-readable storage medium of claim 11, further comprising copying the saved essential TCP/IP connection information into the new connection object if the client is authorized to employ the second TCP/IP connection.

14. The non-transitory computer-readable storage medium of claim 11, further comprising:

receiving another message from another client; and

if the other client is authorized to employ the second TCP/IP connection, and the second TCP/IP connection is available for use, sending at least a portion of the other message to the server over the second TCP/IP connection.

15. An apparatus for forwarding network traffic, comprising:

a non-transitory computer storage medium configured to store TCP/IP connection information associated with connections between clients and servers; and

circuitry coupled to the computer storage medium, wherein the circuitry is arranged to perform actions, comprising;

creating a first TCP/IP connection between a network device and a client;

creating a second TCP/IP connection between the network device and a server;

storing essential TCP/IP connection information associated with each of the first TCP/IP connection and the second TCP/IP connection in a connection object;

allocating a memory for, and storing therein, non-essential TCP/IP connection information in the connection object;

forwarding a first message between the client and the server using the connection object;

saving on a computer storage medium accessible by the network device the essential TCP/IP connection information that was stored in the connection object and freeing the memory allocated in the connection object for non-essential TCP/IP connection information;

receiving, at the network device, a second message from the client;

copying the saved essential TCP/IP connection information into a new connection object; and

forwarding the second message to the server using the new connection object.

16. The apparatus of claim 15, wherein the circuitry is disposed on at least one blade.

17. The apparatus of claim 15, wherein the circuitry includes at least one processor.

18. An apparatus for forwarding network traffic, comprising:

a storage medium that stores state information associated with connections between clients and servers;

an interface that receives messages from a client;

a means for creating a first TCP/IP connection between a network device and a client;

a means for creating a second TCP/IP connection between the network device and a server;

a means for storing essential TCP/IP connection information associated with each of the first TCP/IP connection and the second TCP/IP connection in a connection object;

a means for allocating a memory for, and storing therein, non-essential TCP/IP connection information in the connection object;

a means for forwarding a first message between the client and the server using the connection object;

a means for saving on a computer storage medium accessible by the network device the essential TCP/IP connection information that was stored in the connection object and a means for freeing the memory allocated in the connection object for non-essential TCP/IP connection information;

a means for receiving, at the network device, a second message from the client;

a means for copying the saved essential TCP/IP connection information into a new connection object; and

a means for forwarding the second message to the server using the new connection object.