Relay method, relay apparatus, and computer product

• US 20060174012A1
• Filed: 06/22/2005
• Published: 08/03/2006
• Est. Priority Date: 02/01/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ishitobi, Toshio, Yamazaki, Takeshi
• Granted Patent: US 8,326,916 B2
• Time in Patent Office: Days
• US Class Current: 709/227
• CPC Class Codes: H04L 67/2871 Implementation details of single intermediate entities
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A relay apparatus for relaying a communication between a client and a server includes a determining unit that determines, when the server is to be switched to a standby server, whether connection in an application layer established between the server and the client can be maintained, without depending on an application; and an executing unit that executes a process depending on a result of determination by the determining unit. The process includes a maintaining process for maintaining the connection when the determining unit determines that the connection can be maintained; and a disconnecting process for disconnecting the connection when the determining unit determines that the connection cannot be maintained.

Claims

1. A computer-readable recording medium that stores a relay program for relaying a communication between a client and a server, the relay program making a computer execute:

determining, when the server is to be switched to a standby server, whether connection in an application layer established between the server and the client can be maintained, without depending on an application; and

executing a process depending on a result of determination at the determining, wherein

the process includes

maintaining the connection when it is determined that the connection can be maintained; and

disconnecting the connection when it is determined that the connection cannot be maintained.

2. The computer-readable recording medium according to claim 1, wherein the determining includes determining, in a transmission-control-protocol layer, whether the connection can be maintained, based on a policy specified by a user for each application.

3. The computer-readable recording medium according to claim 2, wherein the policy includes information on a length and an identifier of a message.

4. The computer-readable recording medium according to claim 3, wherein

the determining includes determining whether the server is to be switched to the standby server while a single message is being relayed, based on the length of the message,

if it is determined that the server is to be switched to the standby server while the single message is being relayed, it is determined that the connection can not be maintained, and

otherwise, it is determined that the connection can be maintained.

5. The computer-readable recording medium according to claim 2, wherein the relay program further makes the computer execute editing the policy.

6. The computer-readable recording medium according to claims 1, wherein the maintaining includes maintaining the connection while guaranteeing that sequence numbers of packets transmitted from the server keeps a continuous series before and after a switch of the server to the standby server.

7. A computer-readable recording medium that stores a relay program for a relay apparatus that relays a communication between a client and a server, the relay apparatus including a first computer currently activated and a second computer being an alternative computer when the first computer becomes inactivated, the relay program making the second computer execute:

determining, when the server is to be switched to a standby server, whether connection in an application layer established between the server and the client can be maintained, without depending on an application; and

executing a process depending on a result of determination at the determining, wherein

the process includes

maintaining the connection when it is determined that the connection can be maintained; and

disconnecting the connection when it is determined that the connection cannot be maintained.

8. A relay method for relaying a communication between a client and a server, comprising:

determining, when the server is to be switched to a standby server, whether connection in an application layer established between the server and the client can be maintained, without depending on an application; and

executing a process depending on a result of determination at the determining, wherein

the process includes

maintaining the connection when it is determined that the connection can be maintained; and

disconnecting the connection when it is determined that the connection cannot be maintained.

9. The relay method according to claim 8, wherein the determining includes determining, in a transmission-control-protocol layer, whether the connection can be maintained, based on a policy specified by a user for each application.

10. The relay method according to claim 9, wherein the policy includes information on a length and an identifier of a message.

11. The relay method according to claim 10, wherein

the determining includes determining whether the server is to be switched to the standby server while a single message is being relayed, based on the length of the message,

if it is determined that the server is to be switched to the standby server while the single message is being relayed, it is determined that the connection can not be maintained, and

otherwise, it is determined that the connection can be maintained.

12. The relay method according to claim 9, further comprising editing the policy.

13. The relay method according to claims 8, wherein the maintaining includes maintaining the connection while guaranteeing that sequence numbers of packets transmitted from the server keeps a continuous series before and after a switch of the server to the standby server.

14. A relay apparatus for relaying a communication between a client and a server, comprising:

a determining unit that determines, when the server is to be switched to a standby server, whether connection in an application layer established between the server and the client can be maintained, without depending on an application; and

an executing unit that executes a process depending on a result of determination by the determining unit, wherein

the process includes

a maintaining process for maintaining the connection when the determining unit determines that the connection can be maintained; and

a disconnecting process for disconnecting the connection when the determining unit determines that the connection cannot be maintained.

15. The relay apparatus according to claim 14, wherein the determining unit determines, in a transmission-control-protocol layer, whether the connection can be maintained, based on a policy specified by a user for each application.

16. The relay apparatus according to claim 15, wherein the policy includes information on a length and an identifier of a message.

17. The relay apparatus according to claim 16, wherein

the determining unit determines whether the server is to be switched to the standby server while a single message is being relayed, based on the length of the message,

if it is determined that the server is to be switched to the standby server while the single message is being relayed, the determining unit determines that the connection can not be maintained, and

otherwise, the determining unit determines that the connection can be maintained.

18. The relay apparatus according to claim 17, further comprising an editing unit that edits the policy.

19. The relay apparatus according to claims 14, wherein in the maintaining process, the connection is maintained while the executing unit guaranteeing that sequence numbers of packets transmitted from the server keeps a continuous series before and after a switch of the server to the standby server.