Automatic address distributing system

• US 20010005858A1
• Filed: 02/05/2001
• Published: 06/28/2001
• Est. Priority Date: 08/29/1996
• Status: Active Grant

• Current Assignee: Norihiro Goto, Shuji Ohno, Takashi Kitayama, Tatsuya Watanuki
• Original Assignee: Norihiro Goto, Shuji Ohno, Takashi Kitayama, Tatsuya Watanuki
• Inventors: Ohno, Shuji, Kitayama, Takashi, Goto, Norihiro, Watanuki, Tatsuya
• Granted Patent: US 6,578,088 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 61/45 Network directories; Name-to-address mapping
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092
• CPC Class Codes: H04L 61/5061 Pools of addresses
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 61/5084 Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

An automatic address distributing method, computer program and system for automatically examining addresses already assigned to terminals connected to a network without regard to the status of the existing terminals and removed terminals. An address may be assigned to a terminal by apparatus other than a DHCP server. After a Dynamic Host Configuration Protocol (DHCP) server has been started, addresses currently used in a network are examined by a duplicate-address examining unit and the status of the address are stored in an in-use-address database (DB). When a terminal makes a request for distribution of an address, the DHCP server distributes an address that is currently not used in the network. In the examination carried out by the duplicate-address examining unit, an inquiry about the entire name information controlled by a Domain Name Service (DNS) server is made to the DNS server. Results of the inquiry are also stored in the in-use-address DB. Then, a mobile-agent DB is examined for a mobile agent. An inquiry about information on movement status of mobile terminals is made to the mobile agent cataloged in the mobile-agent DB. Results of this inquiry are also stored in the in-use-address DB.

Claims

1. An automatic address distributing system comprising:

an address distributing server connected to a network system for automatically distributing network information including address information to terminals connected to said network system and avoiding distribution of a duplicate address of an address already used in said network system,

wherein said address distributing server comprises;

a duplicate-address examining apparatus for automatically examining addresses already used by said terminals prior to distribution of an address, and

an in-use-address storing apparatus for storing examination results produced by said duplicate-address examining apparatus.

2. An automatic address distributing system according to

claim 1

, wherein said network system includes a name server for controlling and converting relations between terminal addresses and host names, and

wherein said duplicate-address examining apparatus examines addresses used by said terminals connected to said network system by making an inquiry to said name server.

3. An automatic address distributing system according to

claim 1

, wherein said network system includes a mobility agent for monitoring and supporting a movement of a terminal from said network system to another network system, and

wherein said duplicate-address examining apparatus examines an address used by a terminal having moved to another network system by making an inquiry to said mobility agent.

4. An automatic address distributing system comprising:

an address distributing server connected to a network system for automatically distributing network information including address information to terminals connected to said network system,

wherein said network system comprises;

a mobility agent for supporting a movement of a terminal from said network system to another network system,

wherein said address distributing server is provided with a storage for storing information of said mobility agent, and

wherein said address distributing server when receiving a message transmitted by said mobility agent, said message being used to obtain information on a location and a movement of a terminal connected to said network system, automatically stores information conveyed by said message from said mobility agent in said storage.

5. An automatic address distributing system comprising:

an address distributing server connected to a network system for automatically distributing network information including address information to terminals connected to said network system,

wherein said address distributing server comprises;

a storage for storing an initial validity period, a current validity period and a number of validity-period extensions of each distributed address, and

wherein said address distributing server dynamically modifies said validity period of a distributed address in response to a request for an extension of said validity period made by a terminal corresponding to said distributed address.

6. An automatic address distributing system according to

claim 5

, wherein said address distributing server notifies a terminal owning a distributed address of an extended validity period derived by extension of said current validity period by a product of said initial validity period and said number of validity-period extensions in response to a request for an extension of said validity period made by said terminal.

7. An automatic address distributing system according to

claim 5

, wherein, when an address is distributed to a terminal which used the same address previously, said address distributing server notifies said terminal of a current validity period of said distributed address which is derived by using said previous validity period of said distributed address.

8. An automatic address distributing system comprising:

an address distributing server connected to a network system for automatically distributing network information including address information to terminals connected to said network system,

wherein said network system comprises;

a mobility agent for supporting a movement of a terminal from said network system to another network system,

wherein said address distributing server is provided with a storage for storing an address and information distributed along with said address for each terminal to which said address and said information have been distributed, and

wherein said address distributing server, when the validity period of an address distributed to a terminal with the address of a mobility agent included in said distributed information stored in said storage expires even though said address is still required by said terminal, carries out processing to dynamically change said validity period of said distributed address in the same way as ordinary processing to dynamically change the validity period of an ordinary address distributed to an ordinary terminal in response to a request for extension of said validity period made by said ordinary terminal owning said ordinary address.

9. A method of distributing address information in a network system, comprising the steps of:

automatically distributing network information including address information to terminals connected to said network system in a manner so as to avoid distribution of a duplicate address of an address already used in said network system,

wherein said automatically distributing step comprises the steps of;

automatically examining addresses already used by said terminals prior to distribution of an address, and

storing examination results produced by said examining step for subsequent examination.

10. A method according to

claim 9

, further comprising the steps of:

controlling and converting relations between terminal addresses and host names; and

examining addresses used by said terminals connected to said network system based on said relations.

11. A method according to

claim 9

, further comprising the steps of:

monitoring, supporting, generating information of a movement of a terminal from said network system to another network system; and

examining an address used by a terminal having moved to another network system based on said information of movement of said terminal.

12. A method of distributing address information in a network system, comprising the steps of:

automatically distributing network information including address information to terminals connected to said network system;

supporting a movement of a terminal from said network system to another network system by storing information of a movement of a terminal from said network system to another network system; and

when receiving a message used to obtain information on a location and a movement of a terminal connected to said network system, automatically storing information conveyed by said message in a storage.

13. A method of distributing address information in a network system, comprising the steps of:

automatically distributing network information including address information to terminals connected to said network system;

storing an initial validity period, a current validity period and a number of validity-period extensions of each distributed address; and

dynamically modifying said validity period of a distributed address in response to a request for an extension of said validity period made by a terminal corresponding to said distributed address.

14. A method according to

claim 13

, further comprising the step of:

notifying a terminal owning a distributed address of an extended validity period derived by extension of said current validity period by a product of said initial validity period and said number of validity-period extensions in response to a request for an extension of said validity period made by said terminal.

15. A method according to

claim 13

, further comprising the step of:

when an address is distributed to a terminal which used the same address previously, notifying said terminal of a current validity period of said distributed address which is derived by using said previous validity period of said distributed address.

16. A method of distributing address information in a network system, comprising the steps of:

automatically distributing network information including address information to terminals connected to said network system;

supporting a movement of a terminal from said network system to another network system;

storing an address and information distributed along with said address for each terminal to which said address and said information have been distributed, and

when the validity period of an address distributed to a terminal expires even though said address is still required by said terminal, dynamically changing said validity period of said distributed address in the same way as ordinary processing to dynamically change the validity period of an ordinary address distributed to an ordinary terminal in response to a request for extension of said validity period made by said ordinary terminal owning said ordinary address.

17. A computer program stored on a storage medium executable by a computer for distributing address information in a network system, said computer program when executed by said computer causes said computer to perform the steps of:

automatically distributing network information including address information to terminals connected to said network system in a manner so as to avoid distribution of a duplicate address of an address already used in said network system,

wherein said automatically distributing step comprises the steps of;

automatically examining addresses already used by said terminals prior to distribution of an address, and

storing examination results produced by said examining step for subsequent examination.

18. A computer program according to

claim 17

, when executed by said computer causes said computer to further perform the steps of:

controlling and converting relations between terminal addresses and host names; and

examining addresses used by said terminals connected to said network system based on said relations.

19. A computer program according to

claim 17

, when executed by said computer causes said computer to further perform the steps of:

monitoring, supporting, generating information of a movement of a terminal from said network system to another network system; and

examining an address used by a terminal having moved to another network system based on said information of movement of said terminal.

20. A computer program stored on a storage medium executable by a computer for distributing address information in a network system, said computer program when executed by said computer causes said computer to perform the steps of:

automatically distributing network information including address information to terminals connected to said network system;

supporting a movement of a terminal from said network system to another network system by storing information of a movement of a terminal from said network system to another network system; and

when receiving a message used to obtain information on a location and a movement of a terminal connected to said network system, automatically storing information conveyed by said message in a storage.

21. A computer program stored on a storage medium executable by a computer for distributing address information in a network system, said computer program when executed by said computer causes said computer to perform the steps of:

automatically distributing network information including address information to terminals connected to said network system;

storing an initial validity period, a current validity period and a number of validity-period extensions of each distributed address; and

dynamically modifying said validity period of a distributed address in response to a request for an extension of said validity period made by a terminal corresponding to said distributed address.

22. A computer program according to

claim 21

, when executed by said computer causes said computer to further perform the step of:

notifying a terminal owning a distributed address of an extended validity period derived by extension of said current validity period by a product of said initial validity period and said number of validity-period extensions in response to a request for an extension of said validity period made by said terminal.

23. A computer program according to

claim 21

, when executed by said computer causes said computer to further perform the step of:

when an address is distributed to a terminal which used the same address previously, notifying said terminal of a current validity period of said distributed address which is derived by using said previous validity period of said distributed address.

24. A computer program stored on a storage medium executable by a computer for distributing address information in a network system, said computer program when executed by said computer causes said computer to perform the steps of:

automatically distributing network information including address information to terminals connected to said network system;

supporting a movement of a terminal from said network system to another network system;

storing an address and information distributed along with said address for each terminal to which said address and said information have been distributed, and

when the validity period of an address distributed to a terminal expires even though said address is still required by said terminal, dynamically changing said validity period of said distributed address in the same way as ordinary processing to dynamically change the validity period of an ordinary address distributed to an ordinary terminal in response to a request for extension of said validity period made by said ordinary terminal owning said ordinary address.