Packet distributing system and method for distributing access packets to a plurality of server apparatuses

• US 20030195919A1
• Filed: 03/21/2003
• Published: 10/16/2003
• Est. Priority Date: 03/26/2002
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Higuchi, Hidemitsu, Sugai, Kazuo, Ikeda, Naoya, Atarashi, Yoshifumi, Watanuki, Tatsuya
• Application Number:
  US10/393,451
• Publication Number:
  US 20030195919A1
• Time in Patent Office: Days
• US Class Current: 718/105
• CPC Class Codes: H04L 45/745 Address table lookup; Address filtering
• CPC Class Codes: H04L 61/255 Maintenance or indexing of mapping tables
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1014 based on the content of a request
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• 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 67/63 Routing a service request depending on the request content or context

Abstract

A system includes at least two servers for executing the same application protocol among a plurality of servers, load balancing apparatus respectively connected to the servers, and a router connected to these load balancing apparatuses and to a network. Receiving an access packet from the network, the router selects and routes an arbitrary load balancing apparatus. Receiving the access packet, each load balancing apparatus selects an arbitrary server and transmits the access packet.

Claims

1. A load balancing system for distributing access packets to a plurality of servers prepared for at least one kind of application protocol, comprising:

a plurality of load balancing apparatuses respectively connected to at least two servers for executing the same application protocol among said plurality of servers, each of said load balancing apparatus selecting an arbitrary server when receiving said access packets to said at least two severs, and transmitting said access packet so received to said selected server; and

a router connected to said plurality of load balancing apparatuses and to a network, said router selecting an arbitrary load balancing apparatus from said at least one load balancing apparatus to which at least two servers for executing an arbitrary kind of application protocol are connected, when receiving said access packet to said server for executing said arbitrary kind of application protocol from said network, and routing said access packet so received to said selected load balancing apparatus.

2. A load balancing system according to claim 1, wherein said router includes a route search unit for deciding said load balancing apparatus to which said access packet received is to be transmitted, by use of application protocol information contained in said access packet received.

3. A load balancing system according to claim 1, wherein said router includes a policy routing unit for deciding said load balancing apparatus to which the access packet received is to be transmitted, by use of a destination port number contained in a header of the access packet received and a hash value calculated from information contained in said header.

4. A load balancing system according to claim 1, wherein said router includes a policy routing unit for deciding said load balancing apparatus to which said access packet received is to be transmitted, by use of protocol type information contained in a header of said access packet received and a hash value calculated from arbitrary information contained in said header.

5. A load balancing system according to claim 1, wherein said router includes a storage unit for storing in advance application protocol information, a hash value and routing destination information in association with one another, and a routing unit for judging whether or not said routing destination information, that is associated with said application protocol information contained in a header of said access packet received and with said hash value calculated from arbitrary information contained in said header, is stored in said storage unit, and reading out said routing destination information from said storage unit when said routing destination information is stored in said storage unit.

6. A load balancing system according to claim 1, wherein said router further includes a storage unit for storing in advance information for identifying each of said at least one kind of application protocol, each range of hash values divided into one or more ranges and routing destination information of said access packet in association with one another, and a routing unit for calculating said hash value from arbitrary information contained in a header of said access packet received, and extracting said routing destination information associated with application protocol information contained in said header and with the range in which said calculated hash value is contained.

7. A load balancing system for distributing access packets to a plurality of servers prepared for at least one kind of application protocol, comprising:

a plurality of load balancing apparatuses respectively connected to at least two servers for executing the same application protocol among said plurality of servers, each of said load balancing apparatuses including a balancing unit for selecting an arbitrary server when receiving said access packet to said at least two servers, and transmitting said access packet so received to said selected server; and

a router connected to said plurality of load balancing apparatuses and to a network, said router including;

a plurality of interfaces connected to said network or to each of said load balancing apparatuses;

a storage unit for storing in advance a destination address, application protocol information, a hash value and routing destination information in association with one another; and

a routing unit for judging whether or not a destination address and application protocol information contained in a header of a packet received are stored in said storage unit when receiving said access packet from said network, calculating a hash value from arbitrary information contained in said header when the destination address and the application protocol information are judged as being stored in said storage unit, and extracting said routing destination information associated with said hash value, said destination address and said application protocol information.

8. A load balancing system according to claim 7, wherein said storage unit stores transmission interface information as said routing destination information, and said routing unit extracts said output interface information from said storage unit and outputs the access packet received from an interface identified by said output interface information.

9. A load balancing system according to claim 7, wherein said storage unit stores each range of hash values divided into one or more ranges as the hash values, and said routing unit extracts routing destination information associated with the range in which said calculated hash value is contained.

10. A load balancing system according to claim 7, wherein each of said load balancing apparatuses further includes a second storage unit for storing an address of each of said at least two servers connected thereto, and a translation unit for reading out the address of said arbitrary server selected by said balancing unit from said second storage unit, and translating a destination IP address contained in the access packet received to the address of said arbitrary server.

11. A load balancing system according to claim 7, wherein each of said load balancing apparatuses further includes a second storage unit for storing a representative address allocated in common to said at least two servers in association with the address of each of said servers, and a translation unit for reading out the address of said arbitrary server from said second storage unit when said balancing unit receives an access packet containing said representative address as the destination address and selects an arbitrary server apparatus, and translating a destination IP address contained in the access packet so received to the address of said arbitrary server.

12. A load balancing method in a load balancing system including a plurality of load balancing apparatuses connected to at least two Web servers for executing the same application protocol among a plurality of Web servers prepared for each of at least one kind of application protocol and distributing access packets to said plurality of Web servers, and a router connected to said plurality of load balancing apparatuses and routing the access packet received through a network to each of said load balancing apparatuses, said router executing at least the following steps:

storing look-up key information set in advance;

receiving said access packet from said network;

comparing information contained in a header of said access packet with said look-up key information;

calculating a hash value by use of arbitrary information contained in said header when information contained in said header is coincident with said look-up key information;

deciding one load balancing apparatus from said hash value; and

transmitting said access packet to said load balancing apparatus so decided.

13. A load balancing method according to claim 12, wherein said look-up key information contains application protocol information, and said comparison step compares application protocol information contained in said header with said at least one application protocol information contained in said look-up key.

14. A load balancing method according to claim 13, wherein said decision step selects an arbitrary load balancing apparatus as a load balancing apparatus that should respectively transmit at least two packets having the same application protocol information contained in said header, in accordance with said hash value.

15. A load balancing method according to claim 12, wherein said look-up key information contains a destination address, application protocol information or protocol type information, and said comparison step compares the destination address, the application protocol information or the protocol type information contained in said header with said look-up key information.

16. A load balancing method according to claim 12, wherein said calculation step calculates said hash value by use of a source address contained in said header.

17. A load balancing method according to claim 12, wherein each of said load balancing apparatuses executes the following steps:

storing in advance addresses of said at least two Web servers;

receiving access packets from said router;

deciding a Web server that should transmit the access packet among said at least two Web servers in accordance with a predetermined rule;

translating the destination address contained in said access packet to the address of said Web server stored and so decided; and

transmitting the access packet to said Web server so decided.

18. A load balancing method according to claim 17, wherein each of said load balancing apparatuses further executes the following steps:

storing in advance a representative address allocated in common to said at least two Web servers;

receiving an access packet containing said representative address as a destination address in said reception step;

translating a source address contained in a response packet to said representative address when said load balancing apparatus receives said response packet from said Web server transmitting the access packet; and

transmitting said response packet to said router.