Method and system for a low-overhead mobility management protocol in the internet protocol layer

Abstract

A system and method for supporting mobile Internet communication is provided which employs a Mobile-Home Database (MHD) for Network Address Translation routers (NATs). A plurality of Mobile Nodes (MNs), each having a home network, communicate within the system via a plurality of Hosts. Each Host is associated with a NAT such that each NAT is associated with one network, but one or more Hosts. Each network's NAT's MHD identifies each network's home MNs, with a) a local address of a current association of the MN with a Host within the network or b) a binding defined by a local address of an association of the MN with a Host in a foreign network and the global address of the NAT of the foreign network. Each network's NAT's MHD also identifies each visiting MN with a local address of a current Host association of the MN.

What is claimed is:  
     
         1 . A network system for supporting mobile Internet communication comprising: 
 a plurality of networks, each having: 
 a Network Address Translation router (NAT) with a unique global address;  
 at least one Host associated with the network's NAT; and  
 at least one Mobile Node (MN);  
   each Host having a service area in which it can communicate data to the MNs;    each MN having a home Host in a home network which defines a default local address which is paired with the global address of the home network's NAT to define a default binding of the MN;    the NAT of each network having an associated Mobile-Home Database (MHD) which identifies: 
 each MN, which has the network as its home network, with: 
 a local address of a current association of the MN with a Host in the network, or  
 a binding defined by a local address of an association of the MN with a Host in a different network and the global address of the different network's NAT; and  
 
 each visiting MN, which is a MN currently associated with a Host within the network, but has a different home network, with a local address of the current Host association of the MN;  
   each MN being movable from a location where the MN communicates data via a first associated Host in a first network having a first NAT to: 
 a location within the service area of a second Host within the first network to communicate data via the second Host by communicating to the MHB of the first NAT a local address reflecting the MN's association with the second Host; or  
 a location within the access range of a third Host within a different second network having a second NAT to communicate data via the third Host by communicating to the MHB of the second NAT a local address reflecting the MN's association with the third Host and, where the second network is not the MN's home network, by also communicating to the MHB of the MN's home network's NAT a binding including a new local address reflecting the MN's association with the third Host and the global address of the second NAT;  
   such that a data communication from a corresponding node (CN) to a selected MN is communicated to the selected MN by: 
 establishing a binding based on the MN's default binding or the binding reflected in the MHB of the MN's home network's NAT, and  
 directing the communication to the local address identified for the MN in the MHB of the NAT with which the binding is established.  
   
     
     
         2 . A network system according to  claim 1  wherein at least one network has a plurality of Hosts and at least one Host is the home Host for a plurality of MNs.  
     
     
         3 . A network system according to  claim 1  wherein each network's NAT's MHD identifies local and global addresses and a location field such that: 
 each MN, which has the network as its home network, is identified with: 
 a local address of a current association of the MN with a Host in the network, a null global address, and a home flag in the location field, or  
 a binding defined by a local address of an association of the MN with a Host in a different network and a global address of the different network's NAT and an away flag in the location field; and  
 
 each visiting MN is identified with: 
 a local address of the current Host association of the MN, a null global address, and a home flag in the location field.  
 
 
     
     
         4 . A method for mobile Internet communication system which includes a plurality of networks each having a Network Address Translation router (NAT) and a unique global address, at least one Host associated with the NAT, and at least one Mobile Node (MN), each Host having a service area in which it can communicate data to the MNs, each MN having a home Host and a home network which defines a default local address which is paired with the global address of the HN's NAT to define a default binding of the MN, the method comprising: 
 providing an associated Mobile-Home Database (MHD) for the NAT of each network which identifies: 
 each MN, which has the network as its home network, with: 
 a local address of a current association of the MN with a Host within the network, or  
 a binding defined by a local address of an association of the MN with a Host within a different network and the global address of the different network's NAT; and  
 
 each visiting MN, which is a MN currently associated with a Host within the network, but has a different home network, with a local address of the current Host association of the MN;  
   when a MN moves from a location where the MN communicates data via a first associated Host within a first network having a first NAT to a location within the service area of a second Host within the first network to communicate data via the second Host, communicating to the MHB of the first NAT a local address reflecting the MN's association with the second Host;    when a MN moves from a location where the MN communicates data via the first associated Host within the first network to a location within the access range of a third Host within a different second network having a second NAT, to communicate data via the third Host, communicating to the MHB of the second NAT a local address reflecting the MN's association with the third Host and, where the second network is not the MN's home network, by also communicating to the MHB of the MN's home network's NAT a binding including a new local address reflecting the MN's association with the third Host and the global address of the second NAT; and    communicating a data communication from a corresponding node (CN) to a selected MN by: 
 establishing a binding with a NAT based on the MN's default binding or the binding reflected in the MHB of the MN's home network's NAT, and  
 directing the communication to the local address identified in the MHB of the NAT with which the binding is established for the MN.  
   
     
     
         5 . A method according to  claim 4  wherein: 
 each network's NAT's MHD identifies local and global addresses and a location field such that: 
 each MN, which has the network as its home network, is identified with: 
 a 24 bit local address of a current association of the MN with a Host in the network, a null global address, and a home flag in the location field, or  
 a binding defined by a local address of an association of the MN with a Host within a different network and a global address of the different network's NAT and an away flag in the location field; and  
 
 each visiting MN is identified with: 
 a local address of the current Host association of the MN, a null global address, and a home flag in the location field; and  
 
 
 a binding is established between the CN and an MN based on the binding reflected in the MHB of the MN's home network's NAT when the corresponding location field has an away flag.  
 
     
     
         6 . A Network Address Translation router (NAT) for a network system which includes a plurality of networks, each having a NAT with a unique global address, at least one Host associated with the NAT and at least one Mobile Node (MN), each Host having a service area in which it can communicate data to the MNs, each MN having a home Host and home network which defines a default local address which is paired with the global address of the home network's NAT to define a default binding of the MN, the NAT comprising: 
 a Mobile-Home Database (MHD) which identifies: 
 each MN, which has as its home Host, a Host associated with the NAT, with: 
 a local address of a current association of the MN with a Host associated with the NAT, or  
 a binding defined by a local address of an association of the MN with a Host not associated with the NAT and the global address of the NAT associated with that Host; and  
 
 each MN, which is currently associated with a Host associated with the NAT, but has a home Host which is not associated with the NAT, with a local address of the current Host association;  
   such that a data communication from a corresponding node (CN) to a selected MN which has as its home Host, a Host associated with the NAT, is communicated to the selected MN by: 
 establishing a binding based on the MN's default binding or the binding reflected in the MHB of the NAT, and  
 if the binding is established is established with the NAT, directing the communication to the local address identified in the MHB.  
   
     
     
         7 . A NAT according to  claim 6  wherein the MHD identifies 24 bit local and global addresses and a location field such that: 
 each MN, which has as its home Host, a Host associated with the NAT, is identified with: 
 a 24 bit local address of a current association of the MN with a Host associated with the NAT, a null global address, and a home flag in the location field, or  
 a binding defined by a 24 bit local address of an association of the MN with a Host not associated with the NAT and a 24 bit global address of the NAT associated with that Host and an away flag in the location field; and  
 
 each MN, which is currently associated with a Host associated with the NAT, but has a home Host which is not associated with the NAT, is identified with: 
 a 24 bit local address of the current Host association of the MN, a null global address, and a home flag in the location field.