Mobile communications system and routing management apparatus used in the mobile communications system

Abstract

A mobile communications system is disclosed that includes a first local routing manager (LRM) providing a first network in which a mobile terminal is currently located, a second local routing manager (LRM) providing a second network in which a counterpart terminal communicating with the mobile terminal is currently located, and a home routing manager (HRM) managing correspondence between the unique home address of the counterpart terminal and the second network. The first LRM has a controller that acquires address information of the counterpart terminal from the second LRM, via the HRM, when the first LRM does not have the address information, and communication means that transmits the address information of the counterpart terminal to a router of a new cell in the first network when the mobile terminal moves into the new cell.

1 . A mobile communications system including: 
 a first local routing management apparatus that provides a first network and manages signal routing in the first network in which a mobile terminal is currently located;    a second local routing management apparatus that provides a second network and manages signal routing in the second network in which a counterpart terminal communicating with the mobile terminal is currently located; and    a home routing management apparatus that manages correspondence between a unique home address of the counterpart terminal and the second network, wherein the first local routing management apparatus comprises: 
 a controller that acquires address information about the counterpart terminal from the second local routing management apparatus, via the home routing management apparatus, when the first local routing management apparatus does not have the address information; and  
 communication means that transmits the address information about the counterpart terminal to a router of a new cell in the first network, in response to a request from the router, when the mobile terminal moves into the new cell.  
   
   
   
       2 . A local routing management apparatus providing a first network and managing signal routing for a mobile terminal currently existing in the first network, the mobile terminal communicating with a counterpart terminal located in a second network, the local routing management apparatus comprising: 
 a controller that acquires address information about the counterpart terminal from a second local routing management apparatus of the second network, via a home routing manager that managers correspondence between a unique home address of the counterpart terminal and the second network, when the local routing management apparatus does not have the address information; and    communication means that receives an inquiry about the address information of the counterpart terminal from a router of a new cell in the first network when the mobile terminal moves into the new cell, and transmits the address information of the counterpart terminal to the router in response to the inquiry.    
   
   
       3 . The local routing management apparatus of  claim 2 , wherein the communication means transmits the address information to the router before actual data are transmitted from the mobile terminal to the counterpart terminal.  
   
   
       4 . The local routing management apparatus of  claim 2 , wherein the controller creates a new entry for the address information of the counterpart terminal and records the entry in a table of sending packets.  
   
   
       5 . A local routing management apparatus providing a second network and managing signal routing for a counterpart terminal currently existing in the second network and communicating with a mobile terminal visiting in a first network, the local routing management apparatus comprising: 
 a controller that updates address information about the counterpart terminal in response to a request from a router of a new cell in the second network when the counterpart terminal moves into the new cell;    communication means that reports the updated address information of the counterpart terminal directly to the first network, without passing through a home routing management apparatus that manages correspondence between a home address of the counterpart terminal and the second network; and    a storage that stores an address required to access the first network.    
   
   
       6 . A home routing management apparatus used in a mobile communications system including a first local routing management apparatus providing a first network and managing signal routing in the first network, and a second local routing management apparatus providing a second network and managing signal routing in the second network, the home routing management apparatus comprising: 
 a controller that manages correspondence between a home address of a counterpart terminal and the second network in which the counterpart terminal currently exists, and acquires address information about the counterpart terminal from the second network upon receiving an inquiry from the first local routing management apparatus;    a storage that stores an address required to access the first local routing management apparatus; and    communication means that transmits the address information of the counterpart terminal to the first local routing apparatus in response to the inquiry.    
   
   
       7 . A packet routing method used in a mobile communications system including a first local routing manager providing a first network in which a mobile terminal is currently located, a second local routing manager providing a second network in which a counterpart terminal communicating with the mobile terminal is currently located, and a home routing manager managing correspondence between a unique home address of the counterpart terminal and the second network, the method comprising the steps of: 
 acquiring, at the first local routing manager, address information about the counterpart terminal from the second local routing manager specified based on the correspondence managed by the home routing manager; and    acquiring, at a first router in a new cell in the first network, the address information of the counterpart terminal from the first local routing manager when the mobile terminal moves into the new cell.    
   
   
       8 . The method of  claim 7 , wherein the first router acquires the address information of the counterpart terminal before the first router receives an actual packet transmitted from the mobile terminal to the counterpart terminal.  
   
   
       9 . A packet routing method used in a mobile communicates system including a first local routing manager providing a first network in which a mobile terminal is currently located, a second local routing manager providing a second network in which a counterpart terminal communicating with the mobile terminal is currently located, and a home routing manager managing correspondence between a unique home address of the counterpart terminal and the second network, the method comprising the steps of: 
 acquiring, at the first local routing manager, address information about the counterpart terminal from the second local routing manager based on a request from a first router of a cell in which the mobile terminal is located;    updating, at the second local routing manager, the address information of the counterpart terminal based on a request from a second router of a new cell in the second network when the counterpart terminal moves into the new cell;    reporting the updated address information of the counterpart terminal to the first local routing manager; and    instructing the first router to update the address information of the counterpart terminal.    
   
   
       10 . The method of  claim 9 , further comprising the step of: 
 storing, at the second local routing manger, an address required to access the first local routing manager.