Method and system for forwarding messages received at a traffic manager

• US 8,874,783 B1
• Filed: 12/03/2008
• Issued: 10/28/2014
• 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): THIAW, CATHERINE B
• Application Number:
  US12/327,742
• Time in Patent Office: 2,155 Days
• Field of Search: 709/203, 709/219, 709227-229, 709/238, 370/349
• US Class Current: 709/238
• 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 forwarding messages received at a traffic manager. A traffic manager receives a message from a first connection to a client computer. At least a part of the message is to be forwarded to a server. If a connection exists to the server that matches the first connection, at least a part of the message is forwarded to the server by employing the existing connection. Otherwise, a source address is selected with which to communicate with the server. A new connection that includes the source address and a destination address associated with the server is opened. In addition, information associating the source address and the destination address with the first connection is stored. This information may then be used to map a response received from the server to the first connection.

Claims

1. A traffic manager device for forwarding messages, comprising:

a network interface unit for communicating with a least a client and a plurality of servers; and

a processing unit for executing instructions that enable the traffic manager device to perform actions, including persistently mapping messages between a connection from the client and the plurality of servers to maintain a previous association for the client with a same server in the plurality of servers, wherein information regarding each persistent connection between the traffic manager device and a first server is stored and is retrievable using a single key that is generated from at least a source address that includes a port number in use with at least a second server on behalf of a second client when it is determined that the client and the second client are within a same set of clients as based on a range of addresses, and wherein the source address and the port number are concatenated with at least a destination address to generate the single key such that the concatenated information is employed as an index to a database of connection objects for subsequent comparison with other information associated with a single connection between the traffic manager device and the client, and wherein source addresses in single keys for each of at least two persistent connections include a same source port number such that a received response from the first server is one of a plurality of responses sent to the same port number from at least the first server and the second server.

2. The traffic manager device of claim 1, wherein the messages between the client and at least one of the servers in the plurality of servers employs a hypertext transport protocol (HTTP).

3. The traffic manager device of claim 1, wherein the processing unit is further configured to insert into at least part of a message to be forwarded to one of the servers a hypertext transport protocol (HTTP) header that includes an identification of the client.

4. The traffic manager device of claim 1, wherein at least one message from the client is partitioned into multiple messages by the traffic manager device and distributed across at least two of the servers within the plurality of servers.

5. The traffic manager device of claim 1, wherein the processing unit is configured to perform actions, further including:

when a persistent mapping does not exist for the connection between the traffic manager device and the same server, then;

selecting a source address and port number of the traffic manager device to communicate with one of the servers in the plurality of servers;

opening a new connection with one of the servers using the source address and port number of the traffic manager device; and

generating the single key; and

storing the single key for use as an index for mapping a response received from the server on the new connection to the client.

6. The traffic manager device of claim 5, wherein generating the single key further comprises employing the IP address and port number at which the traffic manager is accessible by the server.

7. A system for managing messages from a client, comprising:

a plurality of servers; and

a traffic manager device that is interposed between the client and the plurality of servers and is configured to perform actions, including;

receiving a message from the client on first connection;

selecting at least a portion of the message to be forwarded to one of the servers in the plurality of servers;

when stored information exists for a previously established connection from the traffic manager device to one of the servers that matches other information regarding the first connection, forwarding the selected portion of the message to the server employing the existing previously established connection, wherein the server received a previous message from the client forwarded by the traffic manager device; and

when stored information does not exist, then;

selecting a source address and port number of the traffic manager device to communicate with one of the servers in the plurality of servers, the port number being in use with at least a second server on behalf of a second client when it is determined that the client and the second client are within a same set of clients as based on a range of addresses;

opening a new connection using the source address and port number of the traffic manager and a destination address and port number associated with the one server; and

storing information associated with the source address and port number of the traffic manager device with other information regarding the first connection, wherein the source address and port number of the traffic manager device are concatenated into a single key used as an index to a dataset of connection objects for mapping a response received from the one server to the first connection.

8. The system of claim 7, wherein the traffic manager device is configured to perform actions, further including:

selecting another portion of the message to be forwarded to another one of the servers in the plurality of servers;

when stored information exists for another previously established connection from the traffic manager device to the other one of the servers that matches other information regarding the first connection, forwarding the selected other portion of the message to the other server employing the other previously established connection, such that another response from the other server enables the traffic manager device to employ the single key to manage the other response to the client using the first connection.

9. The system of claim 7, wherein the traffic manager device is configured to perform actions, further including:

examining the selected portion of the message to select one of the servers.

10. The system of claim 7, wherein the message is encoded using hypertext transport protocol (HTTP).

11. The system of claim 7, wherein another portion of the message is selected and sent to another one of the servers, the other server being selected based on the content of the other portion of the message.

12. The system of claim 7, wherein opening the new connection further comprises activating an unused connection.

13. The system of claim 7, wherein the source address and port number of the traffic manager device are further concatenated with a source address and port number of the one server to generate the single key.

14. A non-transitory machine readable storage medium that is configured to store instructions and data that when installed on a machine enable the machine to perform actions, including:

receiving over a first connection between a client and a traffic manager, a message to be forwarded to at least one server in a plurality of servers, the message being sent using hypertext transport protocol (HTTP); and

persistently mapping the message over the first connection from the client and the plurality of servers to maintain a previous association for the client with a same server in the plurality of servers, wherein information regarding each persistent connection between the traffic manager and a server is stored and is retrievable using a single key that is generated from at least a source address and port number of the traffic manager, the port number being in use with at least a second server on behalf of a second client when it is determined that the client and the second client are within a same set of clients as based on a range of addresses, and that is concatenated with at least a destination address and port number such that the concatenation information is employed as an index to a database of connection objects for subsequent comparisons with other information associated with the first connection between the traffic manager and the client.

15. The non-transitory machine readable storage medium of claim 14, wherein the traffic manager is configured to insert into at least part of a message to be forwarded to one of the servers a hypertext transport protocol (HTTP) header that includes an identification of the client.

16. The non-transitory machine readable storage medium of claim 14, wherein content of one of the messages is examined and when the content indicates requests for more than one content type is included in one of the messages, partitioning the one message into distinct requests based on the content type requested, and selecting different servers from the plurality of servers based on the content type for sending the distinct requests.

17. The non-transitory machine readable storage medium of claim 14, wherein the source address and port number of the traffic manager and a destination address of the same server is stored in a table that associated the single key with the first connection.

18. The non-transitory machine readable storage medium of claim 14, wherein the machine is configured to perform actions, further including:

selecting servers for which to send different portions of the messages based on whether the messages include requests for more than one content type; and

associating each connection with the selected servers with the first connection.

19. The non-transitory machine readable storage medium of claim 14, wherein the persistent mapping further comprises existing connection that matches a set of connection from a set of clients.

20. The non-transitory machine readable storage medium of claim 14, wherein the single key further comprises an identification of the client.