Method and system for support of overlapping IP addresses between an interworking function and a mobile IP foreign agent

• US 6,445,922 B1
• Filed: 12/15/1999
• Issued: 09/03/2002
• Est. Priority Date: 12/15/1999
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Hiller, Thomas Lloyd, Wang, Jin
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): TRAN, TUAN A
• Application Number:
  US09/461,881
• Time in Patent Office: 993 Days
• Field of Search: 455/433, 370/328, 370/338, 370/349, 370/401-409, 709/238
• US Class Current: 455/433
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/72 Subscriber identity
• 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 method and system are disclosed for supporting overlapping IP addresses by sharing a mobile node identifier between an IWF and a Foreign Agent in a visited data (e.g., wireless) network. The mobile node identifier is stored in lookup tables associated with the IWF (Mobile Identity table) and the Foreign Agent (Visitor List table). When a data packet travels between the IWF and the Foreign Agent, the mobile node identifier is attached to it. For data packets moving in the reverse Mobile IP traffic direction (from the mobile node), the Foreign Agent uses the mobile node identifier to identify the correct Home Agent destination by finding the corresponding Home Agent address in the Visitor List table. For forward Mobile IP traffic (to the mobile node), the IWF uses the mobile node identifier to identify the correct mobile node destination by finding the corresponding link identifier in the Mobile Identity table.

Claims

1. In a visited data network wherein data packets are routed to and from two or more mobile nodes that have overlapping home (IP) addresses and are connected to the visited data network, a method for distinguishing between said mobile nodes, comprising the steps of:

acquiring a mobile node identifier from each of said mobile nodes in said visited data network, wherein each mobile node identifier uniquely identifies one of said mobile nodes; and

sharing said mobile node identifier between an Interworking Function network element communicating with said mobile nodes across an air interface and a routing entity (Foreign Agent) providing network access to said mobile nodes.

2. A method in accordance with claim 1 wherein said visited data network is a digital cellular network with IP connectivity to the Internet.

3. A method in accordance with claim 1 wherein said mobile node identifier is a Network Address Identifier (NAI).

4. A method in accordance with claim 1 wherein said acquiring step includes providing said mobile node identifier to said visited data network by establishing a Point to Point Protocol (PPP) and performing a Challenge Handshake Authentication Protocol (CHAP) while using Basic Mobile IP service.

5. A method in accordance with claim 1 wherein said acquiring step includes providing said mobile node identifier to said visited data network by registering said mobile node on said visited data network while using Enhanced Mobile IP service.

8. A method in accordance with claim 1 wherein said sharing step includes storing said mobile node identifier, along with a mobile node home (IP) address and a Home Agent IP address associated with a mobile node identified by said mobile node identifier, in a Visitor List table associated with said Foreign Agent, wherein each entry in said Visitor List table contains a unique combination of said mobile node home address and said Home Agent IP address.

9. A method in accordance with claim 8 further including determining said Home Agent IP address associated with said mobile node from which a data packet is transmitted by either:

performing a lookup in said Visitor List table using a mobile node identifier attached to said data packet and, if more than one entry in said table has a matching mobile node identifier, performing a second lookup from among said matching entries using a home address contained in said data packet;

or

performing a lookup in said Visitor List table using a combination of a mobile node identifier attached to said data packet and a home address contained in said data packet.

6. A method in accordance with claim I wherein said sharing step includes storing said mobile node identifier, along with a home (IP) address and a link identifier that correspond to a mobile node identified by said mobile node identifier, in a Mobile Identity table associated with said Interworking Function, wherein each entry in said Mobile Identity table contains a unique combination of said mobile node identifier and said home address of said mobile node.

7. A method in accordance with claim 6 further including determining said mobile node identifier associated with a mobile node from which a data packet is transmitted by either:

performing a lookup in said Mobile Identity table using a link identifier from said mobile node and, if more than one entry in said Mobile Identity table has a matching link identifier, performing a second lookup from among said matching entries using a home address contained in said data packet'"'"'s header;

or

performing a lookup in said Mobile Identity table using a combination of a link identifier from said mobile node and a home address contained in said data packet'"'"'s header.

10. A method for identifying two different mobile nodes that are connected to the same visited data network and have overlapping home (IP) addresses, comprising the steps of:

providing to said visited data network, for each mobile node, a mobile node address identifier (Network Address Identifier or NAI) that uniquely identifies one of said mobile nodes across said visited data network;

storing said NAIs in a Mobile Identity lookup table associated with an Interworking Function communicating with said mobile nodes and in a Visitor List lookup table associated with a Foreign Agent routing entity providing network access to said mobile nodes;

creating composite data packets each of which includes one of said NAIs bound to a data packet whose origin or destination is one of said mobile nodes which corresponds to said bound NAI;

exchanging said composite packets between said Interworking Function and said Foreign Agent for both forward Mobile IP traffic and reverse Mobile IP traffic;

extracting said NAIs from said composite packets at said Foreign Agent for said composite packets moving in the reverse Mobile IP traffic direction, and at said Interworking Function for said composite packets moving in the forward Mobile IP traffic direction; and

using one of said extracted NAIs to identify a unique route to either a Home Agent corresponding to the mobile node associated with said NAI for reverse Mobile IP traffic or the mobile node associated with said NAI for forward Mobile IP traffic.

11. A method in accordance with claim 10 wherein said visited data network is a digital cellular network with IP connectivity to the Internet.

12. A method in accordance with claim 10 wherein said providing step includes performing a CHAP protocol during PPP establishment to provide said visited data network with said NAI within Basic Mobile IP service.

13. A method in accordance with claim 10 wherein said providing step includes delivering said NAI to said visited data network as part of a mobile node registration request message transmitted within Enhanced Mobile IP service.

14. A method in accordance with claim 10 wherein said storing step includes:

storing each of said NAIs, along with a home (IP) address and a link identifier that correspond to a mobile node identified by said NAI, in an entry of said Mobile Identity table, wherein each entry contains a unique combination of said NAI and said IP address; and

storing each of said NAIs, along with a mobile node home address and a Home Agent IP address associated with a mobile node identified by said NAI, in an entry of said Visitor List table, wherein each entry contains a unique combination of said mobile node home address and said Home Agent IP address.

15. A method in accordance with claim 10 wherein said using step includes either using a combination of said mobile node'"'"'s home address and said NAI, along with said Visitor List table, to identify said unique route to said Home Agent (for reverse Mobile IP traffic), or using said NAI, together with said Mobile Identity table, to identify said unique route to said mobile node (for forward Mobile IP traffic).

16. In a visited data network wherein data packets are routed to and from two or more mobile nodes that have overlapping home (IP) addresses and are connected to the visited data network, a system for distinguishing between said mobile nodes, comprising:

a mobile node identifier corresponding to each of said mobile nodes in said visited data network, wherein each mobile node identifier is provided by and uniquely identifies one of said mobile nodes; and

means for sharing said mobile node identifier between an Interworking Function network element communicating with said mobile nodes across an air interface and a routing entity (Foreign Agent) providing network access to said mobile nodes.

17. A system in accordance with claim 16 wherein said visited data network is a digital cellular network with IP connectivity to the Internet.

18. A system in accordance with claim 16 wherein said mobile node identifier is a Network Address Identifier (NAI).

19. A system in accordance with claim 16 further including means for acquiring said mobile node identifier by establishing PPP and performing the CHAP protocol while using Basic Mobile IP service.

20. A system in accordance with claim 16 further including means for acquiring said mobile node identifier by registering said mobile node on said visited data network while using Enhanced Mobile IP service.

21. A system in accordance with claim 16 wherein said means for sharing said mobile node identifier includes means for storing said mobile node identifier, along with a home (IP) address and a link identifier that correspond to a mobile node identified by said mobile node identifier, in a Mobile Identity table associated with said Interworking Function, wherein each entry in said Mobile Identity table contains a unique combination of said mobile node identifier and said home address of said mobile node.

22. A system in accordance with claim 21 further including means for determining said mobile node identifier associated with a mobile node from which a data packet is transmitted by either:

performing a lookup in said Mobile Identity table using a link identifier from said mobile node and, if more than one entry in said Mobile Identity table has a matching link identifier, performing a second lookup from among said matching entries using a home address contained in said data packet'"'"'s header;

or

performing a lookup in said Mobile Identity table using a combination of a link identifier from said mobile node and a home address contained in said data packet'"'"'s header.

23. A system in accordance with claim 16 wherein said means for sharing said mobile node identifier includes means for storing said mobile node identifier, along with a mobile node home (IP) address and a Home Agent IP address associated with a mobile node identified by said mobile node identifier, in a Visitor List table associated with said Foreign Agent, wherein each entry in said Visitor List table contains a unique combination of said mobile node home address and said Home Agent IP address.

24. A system in accordance with claim 23 further including means for determining said Home Agent IP address associated with said mobile node from which a data packet is transmitted by either:

performing a lookup in said Visitor List table using a mobile node identifier attached to said data packet and, if more than one entry in said Visitor List table has a matching mobile node identifier, performing a second lookup from among said matching entries using a home address contained in said data packet;

or

performing a lookup in said Visitor List table using a combination of a mobile node identifier attached to said data packet and a home address contained in said data packet.

25. A system for identifying two different mobile nodes that are connected to the same visited data network and have overlapping home (IP) addresses, comprising:

a mobile node address identifier (Network Address Identifier or NAI) that is provided for each of said mobile nodes and that uniquely identifies one of said mobile nodes across said visited data network;

means for storing said NAIs in a Mobile Identity lookup table associated with an Interworking Function communicating with said mobile nodes and in a Visitor List lookup table associated with a Foreign Agent routing entity providing network access to said mobile nodes;

composite data packets, each of which includes one of said NAIs bound to a data packet whose origin or destination is one of said mobile nodes which corresponds to said bound NAI;

means for exchanging said composite packets between said Interworking Function and said Foreign Agent for both forward Mobile IP traffic and reverse Mobile IP traffic;

means for extracting said NAIs from said composite packets at said Foreign Agent for said composite packets moving in the reverse Mobile IP traffic direction, and at said Interworking Function for said composite packets moving in the forward Mobile IP traffic direction; and

means for using one of said extracted NAIs to identify a unique route to either a Home Agent corresponding to the mobile node associated with said NAI for reverse Mobile IP traffic or the mobile node associated with said NAI for forward Mobile IP traffic.

26. A system in accordance with claim 25 wherein said visited data network is a digital cellular network with IP connectivity to the Internet.

27. A system in accordance with claim 25 further including means for providing said NAI to said visited data network by performing a CHAP protocol during PPP establishment within Basic Mobile IP service.

28. A system in accordance with claim 25 further including means for providing said NAI to said visited data network as part of a mobile node registration request message transmitted within Enhanced Mobile IP service.

29. A system in accordance with claim 25 wherein said means for storing further includes:

means for storing each of said NAIs, along with a home (IP) address and a link identifier that correspond to a mobile node identified by said NAI, in an entry of said Mobile Identity table, wherein each entry contains a unique combination of said NAI and said IP address; and

means for storing each of said NAIs, along with a mobile node home address and a Home Agent IP address associated with a mobile node identified by said NAI, in an entry of said Visitor List table, wherein each entry contains a unique combination of said mobile node home address and said Home Agent IP address.

30. A system in accordance with claim 25 wherein said means for using extracted NAIs includes means for either using a combination of said mobile node'"'"'s home address and said NAI, along with said Visitor List table, to identify said unique route to said Home Agent (for reverse Mobile IP traffic), or using said NAI, together with said Mobile Identity table, to identify said unique route to said mobile node (for forward Mobile IP traffic).

31. In a visited wireless data network wherein data packets are sent in both directions over a communications pathway that includes, in succession, a visiting mobile wireless node, a Radio Access Network (RAN), an Interworking Function (IWF), and a Foreign Agent routing entity, routing said data packets between said visiting mobile wireless node and a Home Agent routing entity in said visiting mobile wireless node'"'"'s home data network, a method for correctly routing said data packets by distinguishing between said visiting mobile node and another mobile node in said visited wireless data network having the same home address as said visiting mobile wireless node, comprising the steps of:

acquiring, for each mobile node registered on said visited wireless data network, a mobile node identifier (Network Address Identifier or NAI) uniquely identifying one of said registered mobile nodes by performing a CHAP protocol during PPP establishment under Basic Mobile IP or by sending a registration message under Enhanced Mobile IP;

storing said NAI, along with a home (IP) address and a link identifier that correspond to a mobile node identified by said NAI in a Mobile Identity table associated with said IWF during the CHAP or registration phase of Mobile IP service, wherein each entry in said Mobile Identity table contains a unique combination of said NAI and said home address of said mobile node;

storing said NAI, along with a home (IP) address and a Home Agent IP address that correspond to a mobile node identified by said NAI, in a Visitor List table associated with said Foreign Agent during the registration phase of Mobile IP service, wherein each entry in said Visitor List table contains a unique combination of said mobile node home address and said Home Agent IP address;

retrieving, when reverse Mobile IP traffic arrives at said IWF, one of said stored NAIs by using a link identifier from said mobile node and a home address contained in said data packet'"'"'s header, either in combination in a single lookup or successively in two lookups in said Mobile Identity table;

retrieving, when forward Mobile IP traffic arrives at said Foreign Agent, one of said stored NAIs by using home addresses of said mobile node and said Home Agent, either in combination in a single lookup or successively in two lookups in said Visitor List table;

appending said retrieved NAI to data packets exchanged between said IWF and said Foreign Agent, thereby creating composite packets;

extracting said NAI from said composite packets upon receipt thereof at said IWF and said Foreign Agent;

determining said Home Agent'"'"'s IP address when reverse Mobile IP traffic arrives at said Foreign Agent by using said extracted NAI and said mobile node'"'"'s home address either in combination in a single lookup or successively in two lookups in said Visitor List table;

determining said mobile node'"'"'s link identifier when forward Mobile IP traffic arrives at said IWF by using said extracted NAI in a lookup in said Mobile Identity table; and

routing each of said data packets to a correct destination at said Home Agent by using said Home Agent IP address or at said mobile node by using said mobile node'"'"'s link identifier.