Apparatus and method for scalable server load balancing

• US 7,290,059 B2
• Filed: 08/13/2001
• Issued: 10/30/2007
• Est. Priority Date: 08/13/2001
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Yadav, Satyendra
• Primary Examiner(s): BULLOCK JR, LEWIS ALEXANDER
• Application Number:
  US09/929,380
• Publication Number:
  US 20030033428A1
• Time in Patent Office: 2,269 Days
• Field of Search: 709238-244, 709/225
• US Class Current: 709/242
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• 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 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• 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

Abstract

A server hosting system including a server cluster and a plurality of dispatchers, the plurality of dispatchers providing multiple points of entry into the server cluster. The server cluster and plurality of dispatchers are interconnected by a network, such as a system area network. Each of the dispatchers maintains a local dispatch table, and the local dispatch tables of the plurality of dispatchers, respectively, share data over the network.

Claims

1. A method comprising:

receiving a packet at one dispatcher of a plurality of dispatchers, the plurality of dispatchers coupled with a plurality of servers;

searching a local dispatch table of said one dispatcher;

transmitting the packet from said one dispatcher to a server of the plurality of servers if the local dispatch table identifies the server; and

transmitting the packet from said one dispatcher to a locking dispatcher of the plurality of dispatchers if the local dispatch table includes a client lock, the client lock indicating that communications received from a client are to be transmitted to the locking dispatcher until a server is selected for the client,

 

wherein;

the client lock is placed in the local dispatch table by said one dispatcher when said one dispatcher determines that there exists no session entry corresponding to the packet and determines that the client lock does not already exist.

2. The method of claim 1, wherein the local dispatch table includes the client lock, the method further comprising:

selecting a server from the plurality of servers; and

transmitting the packet from the locking dispatcher to the selected server.

3. The method of claim 2, further comprising broadcasting a dispatch table update from the locking dispatcher to all other dispatchers of the plurality of dispatchers, the dispatch table update identifying the selected server and indicating removal of the client lock.

4. A method comprising:

receiving a first packet at one dispatcher of a plurality of dispatchers, the first packet including a connection request from a client;

searching for a session entry corresponding to the first packet;

if the session entry is not found, creating a client lock on packets received from the client and placing the client lock in a local dispatch table corresponding to said one dispatcher, the client lock indicating that packets received from the client are to be transmitted to said one dispatcher until a server is selected for the client; and

broadcasting a dispatch table update from said one dispatcher to all other dispatchers of the plurality of dispatchers, the dispatch table update indicating the client lock; and

receiving at least a second packet at another dispatcher of the plurality of dispatchers; and

transmitting the second packet from said another dispatcher to said one dispatcher.

5. The method of claim 4, further comprising:

selecting a server from a plurality of servers coupled with the plurality of dispatchers; and

transmitting the first packet and the second packet to the selected server.

6. The method of claim 5, further comprising broadcasting another dispatch table update from said one dispatcher to said all other dispatchers, said another dispatch table update identifying the selected server and indicating removal of the client lock.

7. An article of manufacture comprising:

a machine accessible medium, the machine accessible medium providing instructions that, when executed by a machine, cause the machine to;

receive a packet at one dispatcher of a plurality of dispatchers, the plurality of dispatchers coupled with a plurality of servers;

search a local dispatch table of said one dispatcher;

transmit the packet from said one dispatcher to a server of the plurality of servers if the local dispatch table identifies the server; and

transmit the packet from said one dispatcher to a locking dispatcher of the plurality of dispatchers if the local dispatch table includes a client lock, the client lock indicating that communications received from a client are to be transmitted to the locking dispatcher until a server is selected for the client,

wherein;

the client lock is placed in the local dispatch table by said one dispatcher when said one dispatcher determines that there exists no session entry corresponding to the packet and determines that the client lock does not already exist.

8. The article of manufacture of claim 7, the local dispatch table including the client lock, wherein the instructions, when executed, further cause the machine to:

select a server from the plurality of servers; and

transmit the packet from the locking dispatcher to the selected server.

9. The article of manufacture of claim 8, wherein the instructions, when executed, further cause the machine to broadcast a dispatch table update from the locking dispatcher to all other dispatchers of the plurality of dispatchers, the dispatch table update identifying the selected server and indicating removal of the client lock.

10. An article of manufacture comprising:

a machine accessible medium, the machine accessible medium providing instructions that, when executed by a machine, cause the machine to;

receive a first packet at one dispatcher of a plurality of dispatchers, the first packet including a connection request from a client;

search for a session entry corresponding to the first packet;

if the session entry is not found, create a client lock on packets received from the client and placing the client lock in a local dispatch table corresponding to said one dispatcher, the client lock indicating that packets received from the client are to be transmitted to said one dispatcher until a server is selected for the client;

broadcast a dispatch table update from said one dispatcher to all other dispatchers of the plurality of dispatchers, the dispatch table update indicating the client lock; and

receive at least a second packet at another dispatcher of the plurality of dispatchers; and

transmit the second packet from said another dispatcher to said one dispatcher.

11. The article of manufacture of claim 10, wherein the instructions, when executed, further cause the machine to:

select a server from a plurality of servers coupled with the plurality of dispatchers; and

transmit the first packet and the second packet to the selected server.

12. The article of manufacture of claim 11, wherein the instructions, when executed, further cause the machine to broadcast another dispatch table update from said one dispatcher to said all other dispatchers, said another dispatch table update identifying the selected server and indicating removal of the client lock.