Router device, datagram transfer method and communication system realizing handoff control for mobile terminals

• US 6,473,411 B1
• Filed: 05/12/1998
• Issued: 10/29/2002
• Est. Priority Date: 05/12/1997
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Matsuzawa, Shigeo, Tsunoda, Keiji, Moriya, Osamu, Okamoto, Toshio, Kato, Noriyasu, Kumaki, Yoshinari
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Duong, Frank
• Application Number:
  US09/076,065
• Time in Patent Office: 1,631 Days
• Field of Search: 370/310.1, 370/310.2, 370/328, 370/331, 370/352, 370/389, 370/392, 370/399, 370/395.21, 455/436, 455/432, 455/560
• US Class Current: 370/331
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/562 Routing
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/083 wherein at least one of the access points is a moving node
• CPC Class Codes: H04W 40/18 based on predicted events
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 8/087 for preserving data network PoA address despite hand-offs
• 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]

Abstract

A mobile supporting router device for realizing the handoff control associated with the moving in high speed is forms by at least one first interface connected with radio base stations, each capable of accommodating at least one mobile terminal; at least one second interface connected with a wire network; an information exchanging unit for exchanging a routing protocol on a network layer, through the second interface; a memory unit for storing information regarding a routing on the network layer based on the routing protocol exchanged by the information exchanging unit; a transfer unit for transferring datagram through the first interface according to the information regarding the routing on the network layer stored in the memory unit; a moving detection unit for detecting a moving of the mobile terminal among the radio base stations; and an information updating unit for updating the information regarding the routing on the network layer stored in the memory unit when the moving of the mobile terminal is detected by the moving detection unit.

Claims

1. A router device, comprising:

at least one first interface connected with a plurality of radio base stations, each radio base station being capable of accommodating at least one mobile terminal;

at least one second interface connected with a network;

an information exchanging unit configured to exchange a routing protocol on a network layer, through the second interface;

a memory unit configured to store information regarding a routing on the network layer based on the routing protocol exchanged by the information exchanging unit;

a transfer unit configured to transfer datagram through the first interface according to the information regarding the routing on the network layer stored in the memory unit;

a moving detection unit configured to detect a moving of the mobile terminal among the radio base stations;

an information updating unit configured to update the information regarding the routing on the network layer stored in the memory unit when the moving of the mobile terminal is detected by the moving detection unit; and

a switching unit configured to switch transmission of the datagram by the transfer unit between datagram transmission to a radio base station of a visited site of the mobile terminal and datagram transmission to both a radio base station of an originally located site of the mobile terminal and a radio base station of a visited site of the mobile terminal;

wherein when the datagram transmission to both a radio base station of an originally located site of the mobile terminal and a radio base station of a visited site of the mobile terminal is to be used, the information updating unit updates the information regarding the routing on the network layer such that the datagram destined to the mobile terminal is transmitted to both a radio base station of an originally located site of the mobile terminal and a radio base station of a visited site of the mobile terminal.

2. A router device, comprising:

at least one first interface connected with a plurality of radio base stations each radio base station being capable of accommodating at least one mobile terminal;

at least one second interface connected with a network;

an information exchanging unit configured to exchange a routing protocol on a network layer, through the second interface;

a memory unit configured to store information regarding a routing on the network layer based on the routing protocol exchanged by the information exchanging unit;

a transfer unit configured to transfer datagram through the first interface according to the information regarding the routing on the network layer stored in the memory unit;

a moving detection unit configured to detect a moving of the mobile terminal among the radio base stations;

an information updating unit configured to update the information regarding the routing on the network layer stored in the memory unit when the moving of the mobile terminal is detected by the moving detection unit; and

a switching unit configured to switch transmission of the datagram by the transfer unit during an updating processing by the information updating unit between a mode for continuing datagram transmission to a radio base station of an originally located site of the mobile terminal and a mode for stopping datagram transmission to a radio base station of an originally located site of the mobile terminal, according to a communication quality required for transfer of the datagram.

3. A router device, comprising;

at least one first interface connected with a plurality of radio base stations, each radio base station being capable of accommodating at least one mobile terminal;

at least one second interface connected with a network;

an information exchanging unit configured to exchange a routing protocol on a network layer, through the second interface;

a memory unit configured to store information regarding a routing on the network layer based on the routing protocol exchanged by the information exchanging unit;

a transfer unit configured to transfer datagram through the first interface according to the information regarding the routing on the network layer stored in the memory unit;

a moving detection unit configured to detect a moving of the mobile terminal among the radio base stations;

an information updating unit configured to update the information regarding the routing on the network layer stored in the memory unit when the moving of the mobile terminal is detected by the moving detection unit; and

a move over detection unit configured to detect a move over of mobile terminal to a radio base station connected with another router device; and

a control unit configured to update the information regarding the routing on the network layer such that datagram destined to the mobile terminal is transferred to said another router device, and transmit a message for updating the information regarding the routing on the network layer to said another router device such that said another router device transfers the datagram to the mobile terminal, when the move over detection unit detects the move over of the mobile terminal.

4. A router device, comprising:

at least one first interface connected with a plurality of radio base stations, each radio base station being capable of accommodating at least one mobile terminal;

at least one second interface connected with a network;

an information exchanging unit configured to exchange a routing protocol on a network layer through the second, interface;

a memory unit configured to store information regarding a routing on the network layer based on the routing protocol exchanged by the information exchanging unit;

a transfer unit configured to transfer datagram through the first interface according to the information regarding the routing on the network layer stored in the memory unit;

a moving detection unit configured to detect a moving of the mobile terminal among the radio base stations;

an information updating unit configured to update the information regarding the routing on the network layer stored in the memory unit when the moving of the mobile terminal is detected by the moving detection unit; and

a move over detection unit configured to detect a move over of mobile terminal to a radio base station connected with another router device; and

a control unit configured to update the information regarding the routing on the network layer such that datagram destined to the mobile terminal is transferred to a first virtual connection to said another router device which is dedicated for the mobile terminal, and exchange messages with said another router device such that said another router device can carry out a switching on a lower layer of the network layer between the first virtual connection and a second virtual connection from said another router to a radio base station of a visited site of the mobile terminal which is dedicated to the mobile terminal, when the move over detection unit detects the move over of the mobile terminal.