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US006771623B2
(12) United States Patent ao) Patent No.: us 6,771,623 B2
Ton (45) Date of Patent: Aug. 3,2004
(54) METHOD FOR ENSURING RELIABLE MOBILE IP SERVICE
(75) Inventor: Bobby That Dao Ton, Lachine (CA)
(73) Assignee: Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 780 days.
(21) Appl. No.: 09/726,351
(22) Filed: Dec. 1, 2000
(65) Prior Publication Data
US 2002/0067704 Al Jun. 6, 2002
(51) Int. C I. II04Q 7/00
(52) U.S. CI 370/331; 370/401; 370/338;
455/433
(58) Field of Search 370/328, 331,
370/401, 338, 329, 216, 217, 221; 455/435,
433, 436, 453
(56) References Cited
U.S. PATENT DOCUMENTS
6,195,705 Bl * 2/2001 Leung 709/245
6,466,964 Bl * 10/2002 Leung et al 709/202
6,549,522 Bl * 4/2003 Flynn 370/313
6,560,217 Bl * 5/2003 Peirce et al 370/351
6,636,498 Bl * 10/2003 Leung 370/338
FOREIGN PATENT DOCUMENTS
EP 0 950 954 Al 10/1999
EP 1 058 421 A2 6/2000
WO WO 00/18154 3/2000
WO WO 00/18155 3/2000
* cited by examiner
Primary Examiner—Chau Nguyen
Assistant Examiner—Nittaya Juntima
(74) Attorney, Agent, or Firm—Jenkens & Gilchrist
(57) ABSTRACT
The present invention relates to data communications in packet switched networks and more specifically to the mobility of terminals in networks implementing the Mobile Internet Protocol (MIP). In the method according to the present invention each Home Agent will store locally the load information from other Home Agents and will exchange load information with the other Home Agents. The Mobile Node first attempts to register with its primary Home Agent. This registration is not completed due to e.g. failure of the primary Home Agent or where the network chooses to register with another Home Agent which has a lower load than the primary Home Agent. The Mobile Node then attempts to register with a second, alternate, Home Agent. If the alternate Home Agent accepts the request then the Mobile Node is able to access MIP services through the alternate Home Agent. The present invention provides a method to balance the load using dynamic load balancing and a method to recover from Home Agent failure using software Home Agent redundancy.
27 Claims, 5 Drawing Sheets
