Automatic address distributing system

• US 6,578,088 B2
• Filed: 02/05/2001
• Issued: 06/10/2003
• Est. Priority Date: 08/29/1996
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohno, Shuji, Kitayama, Takashi, Goto, Norihiro, Watanuki, Tatsuya
• Primary Examiner(s): Lim, Krisna
• Assistant Examiner(s): Le, Hieu C.
• Application Number:
  US09/775,642
• Publication Number:
  US 20010005858A1
• Time in Patent Office: 855 Days
• Field of Search: 709/201-203, 709/223-224, 709/245, 370/392-393, 370/469, 370/313
• US Class Current: 709/245
• 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; and

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

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

a mobility agent storing apparatus for storing information of at least one mobility agent connected to said network system,

wherein, if said mobility agent storing apparatus holds information of at least one mobility agent connected to said network system, said duplicate-address examining apparatus makes an inquiry to said at least one mobility agent, and obtains an address used by at least one terminal having moved to another network system from said at least one mobility agent,

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.

2. 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;

making an inquiry to at least one mobility agent for supporting a movement of a terminal from said network system to another network system, if said at least one mobility agent is connected to said network system,

receiving, from said at least one mobility agent, at least one address used by at least one terminal having moved to another network system, and

storing said at least one address as the address already used in said network system,

making an inquiry to a name server connected to said network system for controlling and converting relations between terminal addresses and host names;

obtaining address information of terminals connected to said network system, which is maintained by said name server; and

storing said address information as the address already used in said network system.

3. 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;

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

making an inquiry to at least one mobility agent, if said at least one mobility agent is connected to said network system,

receiving, from said at least one mobility agent, at least one address used by at least one terminal having moved to another network system, and

storing said at least one address as the address already used in said network system,

making an inquiry to a name server connected to said network system for controlling and converting relations between terminal addresses and host names;

obtaining address information of terminals connected to said network system, which is maintained by said name server; and

storing said address information as the address already used in said network system.

4. An address distributing server connected to a network for distributing addresses to apparatuses connected to said network, comprising:

an address examining unit which examines addresses already used by existing apparatuses in said network;

an in-use-address storing unit which holds said used addresses;

a mobility agent storing unit which holds address information of mobility agents connected to said network for supporting movements of mobile apparatuses from said network to another one,

wherein, if said address information of at least one mobility agent is stored in said mobility agent storing unit, said address examining unit makes an inquiry to said at least one mobility agent and obtains an address used by at least one mobile apparatus having moved to another network; and

an address distributing unit which distributes an address, which is not duplicate address of any of said addresses held in said in-use-address storing unit, to an apparatus in response to a request from the apparatus,

wherein said address examining unit makes an inquiry to a name server connected to said network for maintaining relations between addresses of said existing apparatus and host names, and obtains said addresses from said name server.

5. An address distributing server connected to a network for distributing addresses to apparatuses connected to said network, comprising:

an address examining unit which examines addresses already used by existing apparatuses in said network;

an in-use-address storing unit which holds said used addresses;

a mobility agent storing unit which holds address information of mobility agents connected to said network for supporting movements of mobile apparatuses from said network to another one,

wherein, if said address information of at least one mobility agent is stored in said mobility agent storing unit, said address examining unit makes an inquiry to said at least one mobility agent and obtains an address used by at least one mobile apparatus having moved to another network, and

an address distributing unit which distributes an address, which is not duplicate address of any of said addresses held in said in-use-address storing unit, to an apparatus in response to a request from the apparatus,

a distributed address storing unit which holds addresses already distributed by said address distributing unit,

wherein said distributed addresses stored in said distributed address storing unit are included in said used addresses stored in said in-use-address storing unit.