Enabling services for multiple sessions using a single mobile node Number:7,130,629 from the United States Patent and Trademark Office (PTO) owispatent

Title: Enabling services for multiple sessions using a single mobile node

Abstract: Methods and apparatus for performing registration on behalf of a session associated with a mobile node are disclosed. The mobile node composes a registration request including a NAI identifying a userID and a sub-NAI that uniquely identifies a session associated with the NAI. The mobile node then sends the registration request. When the Home Agent authenticates the mobile node, the Home Agent returns an IP address associated with the session. The NAI and sub-NAI may then be mapped to this IP address in a mobility binding table associated with the Home Agent as well as a visitor table associated with the Foreign Agent to which the mobile node has roamed.

Patent Number: 7,130,629 Issued on 10/31/2006 to Leung,   et al.

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Inventors:	Leung; Kent K. (Mountain View, CA), Dommety; Gopal (Santa Clara, CA)
Assignee:	Cisco Technology, Inc. (San Jose, CA)
Appl. No.:	09/520,601
Filed:	March 8, 2000

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Current U.S. Class:	455/435.1 ; 370/328; 370/338; 370/351; 370/352; 370/354; 370/400; 370/401; 370/460; 455/432.1; 455/432.3; 455/433; 455/461
Current International Class:	H04Q 7/20 (20060101)
Field of Search:	455/435.1,432.1,433,461 370/338,351,352,354,355,356,389,392,393,400,401,328,460

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References Cited [Referenced By]

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Other References

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Primary Examiner: Milford; Marceau
Attorney, Agent or Firm: Beyer Weaver & Thomas LLP

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Claims

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What is claimed is:

1. In a Foreign Agent, a method of processing a registration request, comprising: receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI associated with the mobile node; providing a sub-NAI in a sub-NAI extension to the registration request, the sub-NAI uniquely identifying a session associated with the mobile node; and sending the registration request to the Home Agent associated with the mobile node.

2. In a mobile node, a method of sending a registration request, comprising: composing a registration request identifying a Home Agent associated with the mobile node; appending a NAI extension including a NAI associated with the mobile node to the registration request; appending a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the mobile node to the registration request; and sending the registration request.

3. The method as recited in claim 2, wherein the NAI identifies a userID submitted during PPP authentication.

4. The method as recited in claim 2, wherein the NAI is an identifier submitted for authentication of the mobile node.

5. The method as recited in claim 2, wherein the NAI is an e-mail address or a userID submitted in an application layer authentication.

6. The method as recited in claim 2, further comprising: detecting the session; wherein composing the registration request is performed in response to the detection of the session.

7. The method as recited in claim 2, wherein the session is associated with a device that is separate from the mobile node.

8. The method as recited in claim 2, wherein the session is associated with an application running on the mobile node.

9. The method as recited in claim 2, further comprising: receiving a registration reply including an IP address associated with the session and identifying the NAI and the sub-NAI; and mapping the NAI and the sub-NAI to the IP address associated with the session.

10. The method as recited in claim 9, wherein the registration reply includes a NAI extension including the NAI and a sub-NAI extension including the sub-NAI.

11. In a Foreign Agent, a method of registering a session with a Home Agent, the method comprising: receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; and sending the registration request to the Home Agent.

12. The method as recited in claim 11, wherein the NAI is a userID submitted during PPP authentication.

13. The method as recited in claim 11, wherein the NAI is an identifier submitted for authentication of the mobile node.

14. The method as recited in claim 11, wherein the NAI is an e-mail address or a userID submitted in an application layer authentication.

15. The method as recited in claim 11, wherein the session is associated with a device that is separate from the mobile node.

16. The method as recited in claim 11, wherein the session is associated with an application running on the mobile node.

17. In a Home Agent, a method of registering a session associated with a mobile node, comprising: receiving a registration request, the registration request including a NAI extension including a NAI identifying a mobile node and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; authenticating the mobile node using the NAI; composing a registration reply; appending a NAI extension to the registration reply, the NAI extension including the NAI identifying the mobile node; and appending a sub-NAI extension to the registration reply, the sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI.

18. The method as recited in claim 17, wherein the NAI is a userID submitted during PPP authentication.

19. The method as recited in claim 17, wherein the session is associated with a device that is separate from the mobile node.

20. The method as recited in claim 17, wherein the session is associated with an application running on the mobile node.

21. In a Home Agent, a method of registering a session associated with a mobile node, comprising: receiving a registration request, the registration request including a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; obtaining an IP address associated with the session; composing a registration reply including the IP address; appending a NAI extension to the registration reply the NAI extension including the NAI; appending a sub-NAI extension to the registration reply, the sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI; and sending the registration reply.

22. The method as recited in claim 21, wherein the NAI identifies a userID submitted during PPP authentication.

23. The method as recited in claim 21, wherein composing the registration reply comprises: providing the IP address in a Home Address field of the registration reply.

24. The method as recited in claim 21, wherein the session is associated with a device that is separate from the mobile node.

25. The method as recited in claim 21, wherein the session is associated with an application running on the mobile node.

26. The method as recited in claim 21, wherein obtaining the IP address for the mobile node comprises: determining whether a mobility binding table associated with the Home Agent includes a binding between the NAI, the sub-NAI and an IP address; when it is determined that the mobility binding table associated with the Home Agent includes a binding between the NAI, the sub-NAI and an IP address, obtaining the IP address from the mobility binding table.

27. The method as recited in claim 26, wherein obtaining the IP address for the mobile node further comprises: when it is determined that the mobility binding table associated with the Home Agent does not include a binding between the NAI, the sub-NAI and an IP address, obtaining a new IP address.

28. The method as recited in claim 26, wherein obtaining the IP address for the mobile node further comprises: when it is determined that the mobility binding table associated with the Home Agent does not include a binding between the NAI, the sub-NAI and an IP address, obtaining an IP address from a Home Address field of the registration request.

29. The method as recited in claim 26, further comprising: when it is determined that the mobility binding table associated with the Home Agent does not include a binding between the NAI, the sub-NAI and an IP address, updating the mobility binding table associated with the Home Agent with an entry mapping the NAI and the sub-NAI to an IP address associated with the mobile node.

30. In a Foreign Agent, a method of processing a registration reply packet received from a mobile node, comprising: receiving a registration reply including an IP address associated with the mobile node, a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; updating a visitor table with a mapping of the NAI, the sub-NAI, and the IP address associated with the mobile node; and sending the registration reply to the mobile node.

31. The method as recited in claim 30, wherein the NAI identifies a userID submitted during PPP authentication.

32. The method as recited in claim 30, wherein the session is associated with a device that is separate from the mobile node.

33. The method as recited in claim 30, wherein the session is associated with an application running on the mobile node.

34. A computer-readable medium for processing a registration request in a Foreign Agent, comprising: instructions for receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI associated with the mobile node; instructions for providing a sub-NAI in a sub-NAI extension to the registration request, the sub-NAI uniquely identifying a session associated with the mobile node; and instructions for sending the registration request to the Home Agent associated with the mobile node.

35. A Foreign Agent adapted for registering a session with a Home Agent, comprising: a processor; and a memory, the memory storing therein: instructions for receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; and instructions for sending the registration request to the Home Agent.

36. A computer-readable medium for registering a session associated with a mobile node in a Home Agent, comprising: instructions for receiving a registration request, the registration request including a NAI extension including a NAI identifying a mobile node and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; instructions for authenticating the mobile node using the NAI; and instructions for composing a registration reply including a NAI extension including the NAI identifying the mobile node and a sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI.

37. A Home Agent configured for registering a session associated with a mobile node, comprising: a processor; and a memory, the memory storing therein: instructions for receiving a registration request, the registration request including a NAE extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; instructions for obtaining an IP address associated with the session; instructions for composing a registration reply including the IP address, a NAI extension including the NAI and a sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI; and instructions for sending the registration reply.

38. A Foreign Agent adapted for processing a registration request, comprising: a processor; and a memory, at least one of the processor and the memory being adapted for: receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI associated with the mobile node; providing a sub-NAI in sub-NAI extension to the registration request, the sub-NAI uniquely identifying a session associated with the mobile node; and sending the registration request to the Home Agent associated with the mobile node.

39. A Foreign Agent adapted for processing a registration request, comprising: means for receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI associated with the mobile node; means for providing a sub-NAI in sub-NAI extension to the registration request, the sub-NAI uniquely identifying a session associated with the mobile node; and means for sending the registration request to the Home Agent associated with the mobile node.

40. A computer-readable medium storing thereon computer-readable instructions for sending a registration request in a mobile node, comprising: instructions for composing a registration request identifying a Home Agent associated with the mobile node; instructions for appending a NAI extension including a NAI associated with the mobile node to the registration request; instructions for appending a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the mobile node to the registration request; and instructions for sending the registration request.

41. A mobile node adapted for sending a registration request, comprising: a processor; and a memory, at least one of the processor and the memory being adapted for: composing a registration request identifying a Home Agent associated with the mobile node; appending a NAI extension including a NAI associated with the mobile node to the registration request; appending a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the mobile node to the registration request; and sending the registration request.

42. A mobile node adapted for sending a registration request, comprising: means for composing a registration request identifying a Home Agent associated with the mobile node; means for appending a NAI extension including a NAI associated with the mobile node to the registration request; means for appending a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the mobile node to the registration request; and means for sending the registration request.

43. A computer-readable medium storing thereon computer-readable instructions for registering a session with a Home Agent in a Foreign Agent, comprising: instructions for receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; and instructions for sending the registration request to the Home Agent.

44. A Foreign Agent adapted for registering a session with a Home Agent, comprising: means for receiving a registration request identifying a Home Agent associated with the mobile node, the registration request further including a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; and means for sending the registration request to the Home Agent.

45. A Home Agent adapted for registering a session associated with a mobile node, comprising: a processor; and a memory, at least one of the processor and the memory being adapted for: receiving a registration request, the registration request including a NAI extension including a NAI identifying a mobile node and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; authenticating the mobile node using the NAI; composing a registration reply; appending a NAI extension to the registration reply, the NAI extension including the NAI identifying the mobile node; and appending a sub-NAI extension to the registration reply, the sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI.

46. A Home Agent adapted for registering a session associated with a mobile node, comprising: means for receiving a registration request, the registration request including a NAI extension including a NAI identifying a mobile node and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; means for authenticating the mobile node using the NAI; means for composing a registration reply; means for appending a NAI extension to the registration reply, the NAI extension including the NAI identifying the mobile node; and means for appending a sub-NAI extension to the registration reply the sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI.

47. A computer-readable medium storing thereon computer-readable instructions for registering a session associated with a mobile node in a Home Agent, comprising: instructions for receiving a registration request, the registration request including a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; instructions for obtaining an IP address associated with the session; instructions for composing a registration reply including the IP address; appending a NAI extension to the registration reply the NAI extension including the NAI; appending a sub-NAI extension to the registration reply, the sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI; and instructions for sending the registration reply.

48. A Home Agent adapted for registering a session associated with a mobile node, comprising: means for receiving a registration request, the registration request including a Nai extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; means for obtaining an IP address associated with the session; means for composing a registration reply including the IP address; appending a NAI extension to the registration reply, the NAI extension including the NAI; appending a sub-NAI extension to the registration reply, the sub-NAI extension including the sub-NAI that uniquely identifies the session associated with the NAI; and means for sending the registration reply.

49. A computer-readable medium storing thereon computer-readable instructions for processing a registration reply packet received from a mobile node in a Foreign Agent, comprising: instructions for receiving a registration reply including an IP address associated with the mobile node, a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; instructions for updating a visitor table with a mapping of the NAI, the sub-NAI, and the IP address associated with the mobile node; and instructions for sending the registration reply to the mobile node.

50. A Foreign Agent adapted for processing a registration reply packet received from a mobile node, comprising: a processor; and a memory, at least one of the processor and the memory being adapted for: receiving a registration reply including an IP address associated with the mobile node, a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; updating a visitor table with a mapping of the NAI, the sub-NAI, and the IP address associated with the mobile node; and sending the registration reply to the mobile node.

51. A Foreign Agent adapted for processing a registration reply packet received from a mobile node, comprising: means for receiving a registration reply including an IP address associated with the mobile node, a NAI extension including a NAI and a sub-NAI extension including a sub-NAI that uniquely identifies a session associated with the NAI; means for updating a visitor table with a mapping of the NAI, the sub-NAI, and the IP address associated with the mobile node; and means for sending the registration reply to the mobile node.

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Description

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to Mobile IP network technology. More particularly, the present invention relates to enabling multiple sessions or services for separate devices or applications associated with a single mobile node.

2. Description of the Related Art

Mobile IP is a protocol which allows laptop computers or other mobile computer units (referred to as "Mobile Nodes" herein) to roam between various sub-networks at various locations--while maintaining internet and/or WAN connectivity. Without Mobile IP or related protocol, a Mobile Node would be unable to stay connected while roaming through various sub-networks. This is because the IP address required for any node to communicate over the internet is location specific. Each IP address has a field that specifies the particular sub-network on which the node resides. If a user desires to take a computer which is normally attached to one node and roam with it so that it passes through different sub-networks, it cannot use its home base IP address. As a result, a business person traveling across the country cannot merely roam with his or her computer across geographically disparate network segments or wireless nodes while remaining connected over the internet. This is not an acceptable state-of-affairs in the age of portable computational devices.

To address this problem, the Mobile IP protocol has been developed and implemented. An implementation of Mobile IP is described in RFC 2002 of the Network Working Group, C. Perkins, Ed., October 1996. Mobile IP is also described in the text "Mobile IP Unplugged" by J. Solomon, Prentice Hall. Both of these references are incorporated herein by reference in their entireties and for all purposes.

The Mobile IP process and environment are illustrated in FIG. 1. As shown there, a Mobile IP environment 2 includes the internet (or a WAN) 4 over which a Mobile Node 6 can communicate remotely via mediation by a Home Agent 8 and a Foreign Agent 10. Typically, the Home Agent and Foreign Agent are routers or other network connection devices performing appropriate Mobile IP functions as implemented by software, hardware, and/or firmware. A particular Mobile Node (e.g., a laptop computer) plugged into its home network segment connects with the internet through its designated Home Agent. When the Mobile Node roams, it communicates via the internet through an available Foreign Agent. Presumably, there are many Foreign Agents available at geographically disparate locations to allow wide spread internet connection via the Mobile IP protocol. Note that it is also possible for the Mobile Node to register directly with its Home Agent.

As shown in FIG. 1, Mobile Node 6 normally resides on (or is "based at") a network segment 12 which allows its network entities to communicate over the internet 4 through Home Agent 8 (an appropriately configured router denoted R2). Note that Home Agent 8 need not directly connect to the internet. For example, as shown in FIG. 1, it may be connected through another router (a router R1 in this case). Router R1 may, in turn, connect one or more other routers (e.g., a router R3) with the internet.

Now, suppose that Mobile Node 6 is removed from its home base network segment 12 and roams to a remote network segment 14. Network segment 14 may include various other nodes such as a PC 16. The nodes on network segment 14 communicate with the internet through a router which doubles as Foreign Agent 10. Mobile Node 6 may identify Foreign Agent 10 through various solicitations and advertisements which form part of the Mobile IP protocol. When Mobile Node 6 engages with network segment 14, Foreign Agent 10 relays a registration request to Home Agent 8 (as indicated by the dotted line "Registration"). The Home and Foreign Agents may then negotiate the conditions of the Mobile Node's attachment to Foreign Agent 10. For example, the attachment may be limited to a period of time, such as two hours. When the negotiation is successfully completed, Home Agent 8 updates an internal "mobility binding table" which specifies the care-of address (e.g., a collocated care-of address or the Foreign Agent's IP address) in association with the identity of Mobile Node 6. Further, the Foreign Agent 10 updates an internal "visitor table" which specifies the Mobile Node address, Home Agent address, etc. In effect, the Mobile Node's home base IP address (associated with segment 12) has been shifted to the Foreign Agent's IP address (associated with segment 14).

Now, suppose that Mobile Node 6 wishes to send a message to a corresponding node 18 from its new location. An output message from the Mobile Node is then packetized and forwarded through Foreign Agent 10 over the internet 4 and to corresponding node 18 (as indicated by the dotted line "packet from MN") according to a standard internet protocol. If corresponding node 18 wishes to send a message to Mobile Node--whether in reply to a message from the Mobile Node or for any other reason--it addresses that message to the IP address of Mobile Node 6 on sub-network 12. The packets of that message are then forwarded over the internet 4 and to router R1 and ultimately to Home Agent 8 as indicated by the dotted line ("packet to MN(1)"). From its mobility binding table, Home Agent 8 recognizes that Mobile Node 6 is no longer attached to network segment 12. It then encapsulates the packets from corresponding node 18 (which are addressed to Mobile Node 6 on network segment 12) according to a Mobile IP protocol and forwards these encapsulated packets to a "care of" address for Mobile Node 6 as shown by the dotted line ("packet to MN(2)"). The care-of address may be, for example, the IP address of Foreign Agent 10. Foreign Agent 10 then strips the encapsulation and forwards the message to Mobile Node 6 on sub-network 14. The packet forwarding mechanism implemented by the Home and Foreign Agents is often referred to as "tunneling."

As described above, the mobile node's IP address (i.e., Home Address) is typically used to identify the mobile node. Thus, when messages are sent to a mobile node, they are sent to that mobile node's IP address. However, in order to enhance the interoperability of roaming and tunneling services, it is desirable to have a standardized method for identifying users. Such a standardized method is proposed in RFC 2486 of the Network Working Group, January 1999, which proposes syntax for the Network Access Identifier (NAI), the userID submitted by a client during Point to Point Protocol (PPP) authentication. Thus, when a client is authenticated based upon the NAI, an IP address may be allocated for use by the client.

When a client is static within a single network, an IP address may be assigned in most cases based solely on the NAI. In addition, as described in Internet Draft "http://search.ietf.org/internet-drafts/draft-ietf-mobileipi-mn-nai-07.tx- t," submitted by the Mobile IP Working Group, Jan. 12, 2000, it has been proposed that the NAI be used to identify a mobile node in order for an IP address (i.e., Home Address) to be assigned. However, this technique is inappropriate in those instances when the client is a mobile node that wishes to roam among different networks. More particularly, when an IP address is assigned by a network access server (NAS), this IP address is assigned based upon the dial in port from a pool of addresses associated with a particular network and therefore the assigned IP address cannot be used within the additional networks to which the mobile node roams. In addition, since the IP address is mapped to the NAI, a problem occurs when more than one node or application wishes to roam using the same mobile node 6 and therefore the same NAI. In other words, when multiple nodes or applications are authenticated based upon the same NAI, a single IP address will be allocated for two different sessions (e.g., devices or applications). Accordingly, mobility cannot be enabled in two different devices or applications based upon the same NAI.

In view of the above, it would be desirable if a mechanism for enabling services to multiple sessions (e.g., devices or applications) via a single or multiple mobile nodes could be established. Moreover, it would be preferable if the sessions could be authenticated using the NAI associated with the mobile node through which the sessions are enabled.

SUMMARY OF THE INVENTION

Methods and apparatus for performing registration on behalf of a session associated with a mobile node are disclosed. A session may be an application (e.g., running on the mobile node) as well as a device that is separate from the mobile node. More particularly, the device need not support Mobile IP. Accordingly, through the present invention, the mobile node may perform a proxy registration on behalf of one or more associated sessions.

In accordance with one aspect of the invention, the mobile node composes a registration request including a NAI identifying a userID (e.g., submitted during PPP authentication) and a sub-NAI that uniquely identifies a session associated with the NAI. For instance, the NAI and sub-NAI may be appended to the registration request in separate extensions to the registration request. The mobile node then sends the registration request to the Home Agent.

In accordance with another aspect of the invention, when the Home Agent authenticates the mobile node based upon information in the registration request, the Home Agent composes and sends a registration reply. In the registration reply, the Home Agent returns an IP address associated with the session. As one example, the IP address may be obtained from the Home Address field of the registration request. As another example, the IP address may be obtained from an entry in a mobility binding table associated with the Home Agent. In addition, the Home Agent may map this IP address to the NAI and sub-NAI in a mobility binding table associated with the Home Agent. Thus, the Home Agent may subsequently use the mobility binding table to route packets addressed to this session via the IP address.

In accordance with yet another aspect of the invention, when the registration reply is received by a Foreign Agent to which the mobile node has roamed, the Foreign Agent may update its visitor table to associate the NAI and sub-NAI with the IP address assigned to that session. In this manner, the Foreign Agent may identify those sessions that are visiting the Foreign Agent.

The present invention enables multiple sessions to be enabled via a single or multiple mobile nodes. This is accomplished through the use of a NAI associated with the mobile node and a sub-NAI that uniquely identifies a session associated with the NAI. Accordingly, multiple Mobile IP sessions may be enabled simultaneously via a single mobile node.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a Mobile IP network segment and associated environment.

FIG. 2 is a block diagram illustrating a Mobile IP network segment and associated environment in which multiple sessions may be enabled through a single mobile node.

FIG. 3 is a process flow diagram illustrating the steps performed during registration on behalf of a new session in accordance with an embodiment of the invention.

FIG. 4 is a process flow diagram illustrating the steps performed during registration by a mobile node in accordance with an embodiment of the invention.

FIG. 5 is a process flow diagram illustrating the steps performed during registration by a Foreign Agent to process a registration request in accordance with an embodiment of the invention.

FIG. 6 is a process flow diagram illustrating the steps performed during registration by a Home Agent in accordance with an embodiment of the invention.

FIG. 7 is a process flow diagram illustrating the steps performed by the Foreign Agent to process a registration reply in accordance with an embodiment of the invention.

FIG. 8 is a diagram illustrating an exemplary registration request that may be sent by a mobile node in accordance with an embodiment of the invention.

FIG. 9 is a diagram illustrating an exemplary registration reply that may be sent by a Home Agent in accordance with an embodiment of the invention.

FIG. 10 is a diagram illustrating an exemplary mobility binding table that may be used by an active Home Agent in accordance with an embodiment of the invention.

FIG. 11 is a diagram illustrating an exemplary visitor table that may be used by an active Foreign Agent in accordance with an embodiment of the invention.

FIG. 12 is a block diagram of a network device that may be configured to implement aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.

As described above, it would be desirable to enable multiple sessions via a single mobile node. A simple solution is to provide a unique NAI for each session. Thus, mobility may be enabled in multiple sessions (e.g., devices or applications) if a user simply specifies a unique NAI when registering via a mobile node. Since the Home Agent associated with the mobile node views the two NAIs as unique, the Home Agent provides different IP addresses. However, this solution is undesirable, since it requires a static mapping of the mobile node 6 to the separate devices or applications. As a result, the user's ability to use new devices with the mobile node 6 would be limited.

Through the use of the present invention, mobility may be enabled by a mobile node on behalf of multiple sessions without requiring a static mapping of the mobile node to the separate devices or applications. Registration is performed on behalf of the sessions by the mobile node through the specification of an NAI associated with the mobile node and a sub-NAI (i.e., session identifier) associated with the session. The session identifier need only be unique within the NAI, and therefore is referred to in the following description as a sub-NAI.

As shown in FIG. 2, it may be desirable to enable two different sessions to be authenticated based upon the same NAI associated with a single mobile node 6. For instance, the NAI may be an e-mail address or a userId submitted in an application layer authentication. The mobile node 6 may be, for example, a phone that supports Mobile IP. Two different users traveling, for instance, in a car or plane, may each wish to connect a laptop to the phone so that each user may separately communicate remotely over the internet via mediation by a Home Agent and a Foreign Agent. For instance, a first user may connect a first laptop (PC1) 20 to the mobile node 6 while a second user may simultaneously connect a second laptop (PC2) 22 to the same mobile node 6. A NAI 24 ("Kleung") associated with the mobile node 6 is submitted in the registration request in order to authenticate the mobile node 6. However, an IP address returned by the Home Agent 8 based upon this authentication will be identical for both users since the NAI 24 is not unique for each session. As a result, the present invention associates a session identifier (i.e., sub-NAI) with each session (e.g., laptop). As shown, a first sub-NAI 26, "KleungPC1," is associated with the first laptop 20 and a second sub-NAI 28, "KleungPC2," is associated with the second laptop 22. Although the sub-NAIs are shown to be strings, the sub-NAI may be implemented in a variety of formats. An IP address may then be allocated by the Home Agent 8 based upon the NAI and associated sub-NAI for the particular session. The IP address may thereafter be used by that session in subsequent communications with a corresponding node. This permits corresponding nodes to continue using the same IP address to communicate with a device or application associated with the mobile node during a given session.

FIG. 3 is a process flow diagram illustrating the steps performed during registration on behalf of a new session in accordance with an embodiment of the invention. As shown at block 302 the mobile node composes and sends a registration request including an NAI and a sub-NAI on behalf of a new session. In addition, the registration request specifies a care-of address of a Foreign Agent to which the session wishes to roam and a Home Agent address associated with the mobile node. The Foreign Agent receives the registration request and forwards the registration request to the Home Agent at block 304. The Home Agent performs authentication based upon the NAI, composes the registration reply with the IP address assigned to that session and sends the registration reply to the Foreign Agent at block 306. At block 308 the Foreign Agent receives the registration reply and forwards the registration reply to the mobile node so that it can map the IP address to the session. Accordingly, the mobile node may subsequently use the IP address to identify packets that are sent by that session as well as packets that are addressed to that session.

As shown at block 302 of FIG. 3, the mobile node is responsible for composing and sending a registration request on behalf of a new session (e.g., device or application). FIG. 4 is a process flow diagram illustrating the steps performed during registration by a mobile node on behalf of a session in accordance with an embodiment of the invention. When the mobile node detects the start of a new session (e.g., application or device) at block 402, the mobile node composes a registration request at block 404. As described in RFC 2002, the registration request must identify the Home Agent associated with the mobile node. In addition, in order to enable the Home Agent to uniquely assign an IP address to the session, a NAI and sub-NAI are specified. More particularly, in accordance with one embodiment, the NAI and sub-NAI are each provided in a separate extension to the registration request. Thus, at block 406, the mobile node appends separate NAI and sub-NAI extensions to the registration request. The NAI extension includes a NAI identifying a userID submitted (e.g., during PPP authentication) while the sub-NAI uniquely identifies a session associated with the NAI. The registration request is then sent at block 408.

As described above with reference to block 304 of FIG. 3, the Foreign Agent is responsible for receiving and forwarding the registration request. FIG. 5 is a process flow diagram illustrating the steps performed during registration by a Foreign Agent to process a registration request in accordance with an embodiment of the invention. As shown at block 502, the Foreign Agent receives the registration request including the NAI and sub-NAI extensions and forwards the registration request to the Home Agent identified by the Home Agent address at block 504.

Once the Home Agent receives the registration request including the NAI and the sub-NAI identifying a session associated with the NAI, it composes a registration reply as described above with reference to block 306 of FIG. 3. FIG. 6 is a process flow diagram illustrating the steps performed during registration by a Home Agent in accordance with an embodiment of the invention. First, the Home Agent authenticates the mobile node. For instance, authentication may be performed using the NAI obtained from the registration request at block 602.

Upon completion of authentication of the mobile node performing the proxy registration on behalf of the associated session, the Home Agent composes and sends a registration reply. In order to provide an IP address for the session, the Home Agent determines whether a binding already exists between the NAI, sub-NAI and an IP address in a mobility binding table associated with the Home Agent at block 604. At block 606, if there is a binding in the mobility binding table for the NAI, sub-NAI and an IP address, this IP address is obtained from the mobility binding table at block 608. Otherwise, the Home Agent decides whether it needs to assign an IP address to the mobile node for this particular session at block 610. For instance, an indicator may be set in the registration request or a specific indicator may be placed in the Home Address field of the registration request. If the Home Agent determines at block 612 that a new IP address is needed, a new IP address is obtained at block 614. Otherwise, the IP address from the Home Ad