Routing method for mobile wireless nodes having overlapping internet protocol home addresses

• US 6,684,256 B1
• Filed: 01/27/2000
• Issued: 01/27/2004
• Est. Priority Date: 01/27/2000
• Status: Expired due to Term

• Current Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Original Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Inventors: Warrier, Chandra, Xu, Yingchun
• Primary Examiner(s): Burgess, Glenton B.
• Assistant Examiner(s): FLYNN, KIMBERLY D
• Application Number:
  US09/491,751
• Time in Patent Office: 1,461 Days
• Field of Search: 709/217, 709/218, 709/223, 709/225, 709/226, 709/229, 709/238, 709/245, 709/249, 370/338, 370/349, 370/389, 370/392, 370/401, 455/433
• US Class Current: 709/238
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/54 Organization of routing tables
• CPC Class Codes: H04L 61/5084 Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server
• 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

In mobile IP wireless data networking, methods are described for correctly routing packets through a foreign agent to or from wireless nodes where the wireless nodes have the same home network IP address. Instead of using normal IP routing, the foreign agent uniquely identifies the wireless node'"'"'s home network IP address and home agent IP address with a PPP link address associated with a PPP link between the foreign agent and the wireless node. This association between PPP link addresses, home agent IP addresses, and home network IP addresses, is preferably implemented in software as a table stored in the foreign agent. The routing of packets through the foreign agent to the mobile nodes is performed by reference to the table. The table allows the foreign agent to correctly and efficiently route packets in the situation where multiple wireless nodes are registered with the foreign agent, but more than one of the wireless nodes have the same home network IP address.

Claims

1. A method of routing a data packet through a foreign agent to a wireless node, comprising the steps of:

receiving said data packet at said foreign agent from a home agent associated with said wireless node;

associating, in said foreign agent, a home Internet Protocol (EP) address and a home agent IP address contained in said data packet with a Point-to-Point Protocol (PPP) link address, said PPP link address associated with a PPP link established between said foreign agent and said wireless node; and

forwarding said data packet through said foreign agent to said PPP link for transmission to said wireless node.

2. The method of claim 1, wherein said foreign agent maintains a table mapping PPP link addresses to unique pairs of home IP addresses and home agent IP addresses, and wherein said step of associating is performed automatically in said foreign agent by reference to said table, whereby multiple wireless nodes having the same home IP addresses but different home agent IP address may be distinguished from each other in said table.

3. The method of claim 2, wherein said foreign agent comprises a remote access server having a plurality of ports, each port for establishing a PPP link with a wireless node.

4. In a foreign agent for a plurality of wireless nodes, an improvement comprising:

providing a software program in said foreign agent for handing routing of packets through said foreign agent for said plurality of wireless nodes having a common home network address, said software program comprising a set of instructions;

(a) maintaining a table uniquely identifying links that connect said foreign agent to said plurality of wireless nodes to home agent addresses and home network addresses for said wireless nodes; and

(b) associating packets to be transmitted to said plurality of wireless nodes to the uniquely identified links,

whereby wireless nodes having the same home network addresses but different home agent addresses may be distinguished from each other in said table and proper routing of packets through said foreign agent to or from said wireless nodes may be achieved.

5. The improvement of claim 4, wherein said table comprises a tunneling table, said tunneling table comprising a plurality of entries, each of said entries corresponding to a respective wireless node of said plurality of wireless node, wherein each of said entries comprises:

a PPP link address;

a home agent Internet protocol (IP) address; and

a home IP address.

6. The improvement of claim 4, wherein said set of instructions comprises:

establishing a point-to-point protocol (PPP) link between a foreign agent (FA) and a respective wireless node of said plurality of wireless nodes;

registering said respective wireless node with said FA;

creating an entry in said table, the entry comprising;

a PPP link address

a FA Internet protocol (IP) address; and

a home IP address;

receiving a data packet from said respective wireless node at said FA;

encapsulating said packet;

forwarding said packet to a home agent.

7. The improvement of claim 4, wherein said set of instructions are executed by a routing card providing an interface between said foreign agent and an Internet Protocol (IP) network.

8. The improvement of claim 4, wherein said foreign agent comprises a remote access server.

9. The improvement of claim 8, wherein said remote access server provides at least 24 ports capable of establishing PPP links with at least 24 wireless mobile nodes, and wherein each of said PPP links is uniquely identified in said table.

10. The improvement of claim 8, wherein said home agent address comprises a home agent Internet Protocol (IP) address, wherein said home network address comprises a home IP address, and wherein said link is uniquely identified by a Point-to-Point Protocol (PPP) link address.

11. A method of routing a data packet through a foreign agent to a mobile wireless node, comprising the steps of:

establishing a Point-to-Point Protocol (PPP) link between said foreign agent and said node, said PPP link having a PPP link address;

processing a registration request message from said node and registering said node;

storing in a table a home agent Internet Protocol (IP) address for a home agent for said node, a home IP address for said node, and a PPP link address for said node;

said home Agent IP address and said home IP address uniquely associated with said PPP link address in said table;

receiving a packet from said home agent;

decapsulating said packet; and

forwarding said packet to said PPP link, said step of forwarding performed by reference to said table.

12. A method of routing a data packet through a foreign agent from a wireless node to a home agent, comprising the steps of:

establishing a Point-to-Point Protocol (PPP) link between said foreign agent and said node, said PPP link having a PPP link address;

processing a registration request message from said node and registering said node;

storing in a table a home agent Internet Protocol (IP) address for said home agent for said node, a home IP address for said node, and a PPP link address for said node, said home Agent IP address and said home IP address uniquely associated with said PPP link address in said table;

receiving a packet from said node via said PPP link;

encapsulating said packet; and

forwarding said packet to said home agent, said step of forwarding performed by reference to said table to determine said home agent IP address from said PPP link address.

13. In a foreign agent for a plurality of wireless nodes, an improvement comprising:

providing a software program in said foreign agent for handling routing of packets through said foreign agent for said plurality of wireless nodes having a common home network address, said software program comprising a set of instructions;

(a) maintaining a table uniquely identifying links that connect said foreign agent to said plurality of wireless nodes to home agent addresses and home network addresses for said wireless nodes; and

(b) associating packets received from said wireless nodes at said foreign agent to home agents for said wireless nodes,

whereby multiple wireless nodes having the same home network addresses but different home agent addresses may be distinguished from each other in said table and proper routing of packets through said foreign agent to said home agents may be achieved.

14. The improvement of claim 13, wherein said table comprises a tunneling table, said tunneling table comprising a plurality of entries, each of said entries corresponding to a respective wireless node of said plurality of wireless node, wherein each of said entries comprises:

a PPP link address;

a home agent Internet protocol (IP) address; and

a home EP address.

15. The improvement of claim 13, wherein said set of instructions comprises:

establishing a point-to-point protocol (PPP) link between a foreign agent (FA) and a respective wireless node of said plurality of wireless nodes;

registering said respective wireless node with said FA;

creating an entry in said table, the entry comprising;

a PPP link address;

a FA Internet protocol (IP) address; and

a home IP address;

receiving a packet from a home agent at said FA, said packet being for delivery to said respective wireless node;

decapsulating said packet to obtain an IP datagram;

forwarding said packet to said respective wireless node based on a comparison of said datagram with said entry in said table.