System for location multicasting and database management for mobile sessions in any computer subnetworks without using a home router of a home subnetwork

• US 5,862,345 A
• Filed: 08/15/1996
• Issued: 01/19/1999
• Est. Priority Date: 02/07/1996
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Okanoue, Kazuhiro, Osawa, Tomoki
• Primary Examiner(s): Luu, Le Hien
• Application Number:
  US08/696,785
• Time in Patent Office: 887 Days
• Field of Search: 370/402, 370/331, 370/312, 370/329, 370/401, 370/913, 455/435, 455/433, 455/432, 369/444.1, 395/200.68
• US Class Current: 709/238
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/50 Address allocation
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: Y10S 370/913 Wireless or radio

Abstract

In a computer network where each mobile host is assigned a subnetwork-independent logical identifier (L-ID), the mobile host acquires a subnetwork-dependent geographical identifier (G-ID) from an agent-existing subnetwork and sends the G-ID to the home subnetwork of the mobile host for location registration if a beacon received therefrom is a first one or different from a previous one or acquires a G-ID from an agentless subnetwork and sends the G-ID to the home subnetwork if no beacons are received. At intervals, a multicast packet is sent from the mobile host, containing the acquired G-ID to the agentless subnetwork. A similar multicast packet is received from a second mobile host and the G-ID contained therein is stored in a database corresponding to the L-ID of the second mobile host. When establishing a session, a data packet is sent from the mobile host to the network along with a G-ID corresponding to a L-ID of the data packet stored in the database. No G-ID is appended if the L-ID of the data packet has no corresponding identifier in the database. At the home subnetwork, a data packet destined to a mobile host of a subnetwork is encapsulated with the G-ID of the mobile host and routed to the subnetwork.

Claims

1. A mobile host for use in a computer network formed of a plurality of interconnected subnetworks which includes a home subnetwork for said mobile host and which are each connected to a respective plurality of other mobile hosts;

said mobile host comprising;

means for periodically transmitting a multicast packet containing a location identifier to a respective one of the plurality of subnetworks to which the mobile host is currently attached, when said one of the subnetworks is not said home subnetwork, for delivery to said other mobile hosts that are connected to said respective one of the subnetworks without using a home router of said home subnetwork;

means for receiving at least another multicast packet from another mobile host via said one of the subnetworks;

a database for storing the location identifier of the received multicast packet; and

means for transmitting a data packet to said one of the subnetworks together with a location identifier when the destination of the data packet corresponds to said stored location identifier and for transmitting said data packet without a location identifier to said one of the subnetworks when said destination has no corresponding stored location identifier.

2. A mobile host as claimed in claim 1, further comprising means for measuring a time lapse from the reception of said multicast packet, resetting the measured time lapse to zero in response to reception of a subsequent multicast packet, and erasing a corresponding location identifier from the database when the measured time lapse exceeds a critical value.

3. A mobile host as claimed in claim 1, wherein said another mobile host is attached to said one of the subnetworks.

4. A mobile host for use in a computer network formed of a plurality of interconnected subnetworks each connected to a respective plurality of other mobile hosts, at least a portion of said plurality of subnetworks each periodically transmitting a respective beacon uniquely identifying its respective subnetwork, a respective one of said subnetworks operating as a home subnetwork for the mobile host, said mobile host comprising:

means for acquiring a location identifier from a first type subnetwork and for transmitting the location identifier to the home subnetwork to represent location registration data of said mobile host when an initial beacon is received and when a beacon different from a previous one is received and for acquiring a location identifier from a second type subnetwork and transmitting the location identifier to the home subnetwork to represent said location registration data when no beacons are received for a predetermined period;

means for periodically transmitting a multicast packet containing the acquired location identifier to said second type subnetwork for delivery to said other mobile hosts that are connected to said second type subnetwork when said location identifier is acquired from said second type subnetwork without using a home router of said home subnetwork;

means for receiving at least another multicast packet from another mobile host via said second type subnetwork when said location identifier is acquired from said second type subnetwork;

a database for storing another location identifier which is contained in the received multicast packet; and

means for transmitting a data packet to one of said first type subnetwork and said second type subnetwork together with a location identifier when the destination of the packet corresponds to said stored location identifier and for transmitting said data packet to said one of said first type subnetwork and said second type subnetwork without a location identifier when said destination has no corresponding stored location identifier.

5. A mobile host as claimed in claim 4, further comprising means for measuring a time lapse from the reception of said multicast packet, resetting the measured time lapse to zero in response to reception of a subsequent multicast packet, and erasing a corresponding location identifier from the database when the measured time lapse exceeds a critical value.

6. A mobile host as claimed in claim 4, wherein said another mobile host is attached to said second type subnetwork.

7. A mobile host as claimed in claim 4 wherein said first type subnetwork includes a subnetwork agent and wherein said second type subnetwork comprises an agentless subnetwork.

8. A computer network comprising:

a plurality of mobile hosts, each of the mobile hosts being assigned a logical identifier;

a plurality of interconnected subnetworks in which at least a portion of said subnetworks periodically transmit a corresponding beacon uniquely identifying its respective subnetwork, one of said subnetworks operating as a home subnetwork for one of said mobile hosts;

each of said mobile hosts comprising;

means for acquiring a geographical identifier from a first type subnetwork and for transmitting the geographical identifier to the home subnetwork to represent location registration data of said mobile host when an initial beacon is received and when a beacon different from a previous one is received and for acquiring a geographical identifier from a second type subnetwork and transmitting the geographical identifier to the home subnetwork to represent said location registration data when no beacons are received for a predetermined period;

means for periodically transmitting a multicast packet containing the acquired geographical identifier to said second type subnetwork for delivery to other mobile hosts that are connected to said second type subnetwork when said location identifier is acquired from said second type subnetwork without using a home router of said home subnetwork;

means for receiving at least another multicast packet from another mobile host via said second type subnetwork when said location identifier is acquired from said second type subnetwork;

a database for storing another geographical identifier which is contained in the received multicast packet and which corresponds to the logical identifier of said another mobile host; and

means for transmitting a data packet to one of said first type subnetwork and said second type subnetwork together with a stored geographical identifier corresponding to a logical identifier of the data packet when said logical identifier corresponds to said stored geographical identifier and for transmitting said data packet to said one of said first type subnetwork and said second type subnetwork without a geographical identifier if the logical identifier of the data packet has no corresponding stored geographical identifier,

said home subnetwork including means for encapsulating a data packet destined for one of said mobile hosts together with the geographical identifier received from said one of said mobile hosts and forwarding the encapsulated data packet to the corresponding subnetwork connected to said one of said mobile hosts.

9. A mobile host as claimed in claim 8 wherein said first type subnetwork includes a subnetwork agent and wherein said second type subnetwork comprises an agentless subnetwork.

10. In a computer network formed of a plurality of interconnected subnetworks which includes a hone subnetwork for said mobile host and which are each connected to a respective plurality of mobile hosts, a method comprising the steps of:

transmitting, periodically by a respective mobile host, a multicast packet containing a location identifier to a respective one of the plurality of subnetworks to which said respective mobile host is currently attached, when said one of the subnetworks is not said home subnetwork, for delivery to other mobile hosts that are connected to said respective one of the subnetworks without usina a hone router of said home subnetwork;

receiving, at said mobile host, at least another multicast packet via said one of the subnetworks and storing the location identifier of the received multicast packet in a database; and

transmitting a data packet from the mobile host to said one of the subnetworks together with a location identifier when the destination of the data packet corresponds to said second location identifier and for transmitting said data packet from the mobile host to said one of the subnetworks without a location identifier when said destination has no corresponding stored location identifier.

11. A method as claimed in claim 10, further comprising the steps of measuring a time lapse from the reception of said multicast packet, resetting the measured time lapse to zero in response to reception of a subsequent multicast packet, and erasing a corresponding location identifier from the database when the measured time lapse exceeds a critical value.

12. In a computer network formed of a plurality of interconnected subnetworks each connected to a respective plurality of mobile hosts, at least a portion of said plurality of subnetworks each periodically transmitting a respective beacon uniquely identifying its corresponding subnetwork, a respective one of said subnetworks operating as a home subnetwork for a respective mobile host, a method comprising the steps of:

acquiring, by said respective mobile host, a location identifier from a first type subnetwork and transmitting the location identifier to the home subnetwork to represent location registration data of said respective mobile host when an initial beacon is received and when a beacon different from a previous one is received, and acquiring a location identifier from a second type subnetwork and transmitting the location identifier to the home subnetwork to represent said location registration data when no beacons are received for a predetermined period;

transmitting, periodically by said respective mobile host, a multicast packet containing the acquired location identifier from said mobile host to said second type subnetwork for delivery to said other mobile hosts that are connected to said second type subnetwork when said location identifier is acquired from said second type subnetwork without using a home router of-said home subnetwork;

receiving, at said mobile host, at least another multicast packet via said second type subnetwork when said location identifier is acquired from said second type subnetwork and storing another location identifier which is contained in the received multicast packet in a database; and

transmitting a data packet from the mobile host to one of said first type subnetwork and said second type subnetwork together with a location identifier when the destination of the data packet corresponds to said stored location and transmitting said data packet from the mobile host to said one of said first type subnetwork and said second type subnetwork without a location identifier when said destination has no corresponding stored location identifier.

13. A method as claimed in claim 12, further comprising the steps of measuring a time lapse from the reception of said multicast packet, resetting the measured time lapse to zero in response to reception of a subsequent multicast packet, and erasing a corresponding location identifier from the database when the measured time lapse exceeds a critical value.

14. In a computer network comprising a plurality of mobile hosts and a plurality of interconnected subnetworks in which a portion of said plurality of subnetworks periodically transmit a corresponding beacon uniquely identifying the respective subnetwork, one of said subnetworks operating as a home subnetwork for one of said mobile hosts, each of the mobile hosts being assigned a logical identifier, a method comprising the steps of:

acquiring, by a respective one of such mobile hosts, a geographical identifier from a first type subnetwork and transmitting the geographical identifier to the home subnetwork to represent location registration data of said mobile host when. an initial beacon is received and when a beacon different from a previous one is received, and acquiring a geographical identifier from a second type subnetwork and transmitting the geographical identifier to the home subnetwork to represent said location registration data when no beacons are received for a predetermined period;

transmitting, periodically by said respective mobile host, a multicast packet containing the acquired geographical identifier from a mobile host to said second type subnetwork for delivery to said other mobile hosts that are connected to said second type subnetwork when said location identifier is acquired from said second type subnetwork without using a hone router of said home subnetwork;

receiving, at said mobile host, at least another multicast packet from another mobile host via said type second subnetwork when said location identifier is acquired from said second type subnetwork and storing another geographical identifier which is contained in the received multicast packet in a database and which corresponds to the logical identifier of said another mobile host;

transmitting a data packet from the mobile host to one of said first type subnetwork and said second type subnetwork together with a geographical identifier corresponding to a logical identifier of the data packet stored in the database when said logical identifier corresponds to said stored geographical identifier and transmitting said data packet from the mobile host to said one of said first t e subnetwork and said second type subnetwork without a geographical identifier if the logical identifier of the data packet has no corresponding stored geographical identifier; and

encapsulating, at said home subnetwork, a data packet destined for one of said mobile hosts together with the geographical identifier received from said one of said mobile hosts and forwarding the encapsulated data packet to the corresponding subnetwork connected to said one of said mobile hosts.

15. A mobile host for use in a computer network formed by a plurality of interconnected subnetworks which includes a home subnetwork for said mobile host and which are each connected to a respective plurality of other mobile hosts;

said mobile host comprising;

a first transmitter for periodically transmitting a multicast packet containing a location identifier to a respective one of the plurality of subnetworks to which the mobile host is currently attached, when said one of the subnetworks is not said home subnetwork, for delivery to said other mobile hosts that are connected to said respective one of the subnetworks without using a home router of said home subnetwork;

a receiver for receiving at least another multicast packet from another mobile host via said one of the subnetworks;

a database for storing the location identifier of the received multicast packet; and

a second transmitter for transmitting a data packet to said one of the subnetworks together with a location identifier when the destination of the data packet corresponds to said stored location identifier and for transmitting said data packet without a location identifier to said one of the subnetworks when said destination has no corresponding stored location identifier.

16. A mobile host as claimed in claim 15, further comprising a measurer for measuring a time lapse from the reception of said multicast packet, resetting the measured time lapse to zero in response to reception of a subsequent multicast packet, and erasing a corresponding location identifier from the database when the measured time lapse exceeds a critical value.

17. A mobile host as claimed in claim 15, wherein said another mobile host is attached to said one of the subnetworks.

18. A mobile host for use in a computer network formed by a plurality of interconnected subnetworks each connected to a respective plurality of other mobile hosts, at least a portion of said plurality of subnetworks each periodically transmitting a respective beacon uniquely identifying its respective subnetwork, a respective one of said subnetworks operating as a home subnetwork for the mobile host, said mobile host comprising:

an acquirer for acquiring a location identifier from a first type subnetwork and for transmitting the location identifier to the home subnetwork to represent location registration data of said mobile host when an initial beacon is received and when a beacon different from a previous one is received and for acquiring a location identifier from a second type subnetwork and transmitting the location identifier to the home subnetwork to represent said location registration data when no beacons are received for a predetermined period;

a first transmitter for periodically transmitting a multicast packet containing the acquired location identifier to said second type subnetwork for delivery to said other mobile hosts that are connected to said second type subnetwork when said location identifier is acquired from said second type subnetwork without using a home router of said home subnetwork;

a receiver for receiving at least another multicast packet from another mobile host via said second type subnetwork when said location identifier is acquired from said second type subnetwork;

a database for storing another location identifier which is contained in the received multicast packet; and

a second transmitter for transmitting a data packet to one of said first type subnetwork and said second type subnetwork together with a location identifier when the destination of the packet corresponds to said stored location identifier and for transmitting said data packet to said one of said first type subnetwork and said second type subnetwork without a location identifier when said destination has no corresponding stored location identifier.

19. A mobile host as claimed in claim 18, further comprising a measurer for measuring a time lapse from the reception of said multicast packet, resetting the measured time lapse to zero in response to reception of a subsequent multicast packet, and erasing a corresponding location identifier from the database when the measured time lapse exceeds a critical value.

20. A mobile host as claimed in claim 18, wherein said another mobile host is attached to said second type subnetwork.

21. A mobile host as claimed in claim 18 wherein said first type subnetwork includes a subnetwork agent and wherein said second type subnetwork comprises an agentless subnetwork.

22. A computer network comprising:

a plurality of mobile hosts, each of the mobile hosts being assigned a logical identifier;

a plurality of interconnected subnetworks in which at least a portion of said subnetworks periodically transmit a corresponding beacon uniquely identifying its respective subnetwork, one of said subnetworks operating as a home subnetwork for one of said mobile hosts;

each of said mobile hosts comprising;

an acquirer for acquiring a geographical identifier from a first type subnetwork and for transmitting the geographical identifier to the home subnetwork to represent location registration data of said mobile host when an initial beacon is received and when a beacon different from a previous one is received and for acquiring a geographical identifier from a second type subnetwork and transmitting the geographical identifier to the home subnetwork to represent said location registration data when no beacons are received for a predetermined period;

a first transmitter for periodically transmitting a multicast packet containing the acquired geographical identifier to said second type subnetwork for delivery to other mobile hosts that are connected to said second type subnetwork when said location identifier is acquired from said second type subnetwork without using a home router of said home subnetwork;

a receiver for receiving at least another multicast packet from another mobile host via said second type subnetwork when said location identifier is acquired from said second type subnetwork;

a database for storing another geographical identifier which is contained in the received multicast packet and which corresponds to the logical identifier of said another mobile host; and

a second transmitter for transmitting a data packet to one of said first type subnetwork and said second type subnetwork together with a stored geographical identifier corresponding to a logical identifier of the data packet when said logical identifier corresponds to said stored geographical identifier and for transmitting said data packet to said one of said first type subnetwork and said second tore subnetwork without a geographical identifier when the logical identifier of the data packet has no corresponding stored geographical identifier,

said home subnetwork including an encapsulator for encapsulating a data packet destined for one of said mobile hosts together with the geographical identifier received from said one of said mobile hosts and forwarding the encapsulated data packet to the corresponding subnetwork connected to said one of said mobile hosts.

23. A mobile host as claimed in claim 22 wherein said first type subnetwork includes a subnetwork agent and wherein said second type subnetwork comprises an agentless subnetwork.