Seamless user mobility in a short-range wireless networking environment

• US 6,975,864 B2
• Filed: 06/09/2003
• Issued: 12/13/2005
• Est. Priority Date: 08/11/2000
• Status: Expired due to Fees

• Current Assignee: Reefedge Networks LLC (IPNav)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Singhal, Sandeep Kishan, Gopal, Ajei Sarat, Gopal, Inder Sarat
• Primary Examiner(s): FERGUSON, KEITH
• Application Number:
  US10/457,573
• Publication Number:
  US 20030195002A1
• Time in Patent Office: 918 Days
• Field of Search: 455/403, 455/422.1, 4554141-4144, 455436-445, 4554321-4323, 455/435.1, 455/435.2, 455/450, 455/451, 455/452.1, 455/500, 455/517, 455/509, 455/511, 455/550.1, 455/552.1, 455/553.1, 370/466, 370/331, 370/332, 709/225, 709/203
• US Class Current: 455/438
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/50 Address allocation
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 67/04 specially adapted for terminals or networks with limited capabilities; specially adapted for terminal portability
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber 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]
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention provides methods, systems, and computer program instructions for enabling a variety of devices, particularly low-power hand-held devices, to travel seamlessly through a networking environment such as that encountered within a building by establishing connectivity to a plurality of network access points. The illusion of seamless network connectivity is provided by having these access points coordinate with a core server to perform user authentication, device address assignment, and handoff services.

Claims

1. A method of enabling seamless user mobility in a short-range wireless networking environment, comprising the steps of:

providing a plurality of Handoff Management Points (HMPs), each of the HMPs equipped with a short-range wireless link for communication with one or more client devices and a link to a networking environment wherein one or more application programs residing on one or more application servers can be accessed, wherein each of the client devices is equipped with a short-range wireless communications capability for communicating in the short-range wireless networking environment;

making a particular one of the client devices known to a first one of the HMPs when the particular client device comes into communication range of the first HMP;

obtaining, by the first HMP, a network address for the particular client device, wherein the network address is usable by the particular client device for accessing one or more of the application programs; and

handing the particular client device off from the first HMP to a second one of the HMPs, when the particular client device leaves the communication range of the first HMP and enters the communication range of the second HMP, such that any on-going session operating between the particular client device and one or more of the application programs is maintained, by continuing to use the same network address for the particular client device after the particular client device is handed off to the second HMP.

2. The method according to claim 1, wherein an installation and a configuration of each HMP, as it becomes operational, requires no incremental intervention by a systems administrator.

3. The method according to claim 1, further comprising a process for dynamically making a selected one of the HMPs operational, comprising the steps of:

obtaining a network address for the selected HMP;

discovering, by the selected HMP, an identity of a Handoff Core Server that manages the HMPs; and

notifying the Handoff Core Server, by the selected HMP, that the selected HMP is operational.

4. The method according to claim 3, wherein the step of obtaining a network address further comprises issuing, by the selected HMP, a Dynamic Host Configuration Protocol (DHCP) request and receiving a response thereto, wherein the response provides the network address for the selected HMP.

5. The method according to claim 4, wherein the response further provides a network address of the Handoff Core Server and the step of discovering an identity of the Handoff Core Server further comprises the step of inspecting the response and locating the network address of the Handoff Core Server therein.

6. The method according to claim 3, wherein the step of discovering an identity of the Handoff Core Server further comprises the steps of:

issuing, by the selected HMP, a Service Location Protocol (SLP) request; and

receiving a response thereto, wherein the response provides the identity.

7. The method according to claim 3, wherein each operational HMP periodically notifies the Handoff Core Server that the notifying HMP remains operational.

8. The method according to claim 3, wherein the notification to the Handoff Core Server provides the obtained network address of the selected HMP and a link-layer address of the selected HMP.

9. The method according to claim 1, wherein the step of making the particular client device known to the first HMP further comprises the step of receiving, by the first HMP, a Dynamic Host Configuration Protocol (DHCP) request requests generated by the particular client device.

10. The method according to claim 9, further comprising the step of:

forwarding, by the first HMP to a Handoff Core Server that manages the HMPs, the received DHCP request; and

wherein the obtaining step further comprises the steps of;

obtaining, by the Handoff Core Server responsive to receiving the forwarded DHCP request, the network address for the particular client device, wherein the obtained network address is a newly-obtained network address if the Handoff Core Server has not previously obtained a network address for the particular client device and is an already-obtained network address that the Handoff Core Server has previously obtained for the particular client device otherwise;

forwarding the obtained network address from the Handoff Core Server to the first HMP; and

forwarding, by the first HMP, a DHCP response to the particular client device, thereby notifying the particular client device of the network address it is to use.

11. The method according to claim 10, wherein the step of obtaining a network address by the Handoff Core Server further comprises the steps of:

consulting a repository where entries for already-obtained network addresses are stored in correspondence with the client device for which they were obtained;

newly obtaining a network address and using this newly-obtained address as the obtained network address if the consulting step fails to locate an entry in the repository for the particular client device; and

retrieving the already-obtained network address for the particular client device from the repository entry for the particular client device, otherwise, and using this retrieved network address as the obtained address.

12. The method according to claim 9, further comprising the steps of:

forwarding the received DHCP request, by the first HMP, to a Handoff Core Server that manages the HMPs;

obtaining, by the Handoff Core Server, the network address for the particular client device; and

returning, by the Handoff Core Server, the obtained network address to the first HMP.

13. The method according to claim 12, wherein the step of obtaining the network address by the Handoff Core Server further comprises the step of:

determining, by the Handoff Core Server, whether a network address has already been obtained for the particular client device; and

wherein the returning step further comprises the steps of;

returning the already-obtained network address if the determining step has a positive result;

returning a newly-obtained network address if the determining step has a negative result; and

remembering the newly-obtained network address as the already-obtained address for the particular client device for which it was newly obtained.

14. The method according to claim 1, further comprising the step of remembering, by a Handoff Core Server that manages the HMPs, which client device is currently communicating through which HMP(s).

15. The method according to claim 14, wherein the remembering step further comprises recording, in a repository, a correspondence between each of the client devices and the one or more HMPs through which that client device is currently communicating.

16. The method according to claim 15, further comprising the step of providing one or more Application Programming Interfaces (APIs) through which the application programs may retrieve information from the repository about which client device is currently communicating through which HMP(s).

17. The method according to claim 16, wherein the Handoff Core Server also remembers a physical location of each client device, and wherein a selected one of the application programs invokes one of the APIs to retrieve information about which particular HMP(s) a selected client device is currently communicating through, and uses the retrieved information to provide location-based services whereby one of the particular HMPs will be selected for the location-based services, based on the remembered physical location of the selected client device.

18. The method according to claim 16, wherein the Handoff Core Server also remembers which user is using each client device, and wherein a selected one of the application programs invokes one of the APIs to retrieve information about which user is using a selected client device, and uses the retrieved information to provide personalized services for the user of the selected client device.

19. The method according to claim 18, wherein:

the Handoff Core Server also remembers a physical location of each client device; and

the selected application program provides temperature control, and thereby sets a temperature at the physical location of the selected client device according to preferences of the user of the selected client device.

20. The method according to claim 1, further comprising the step of remembering, by a Handoff Core Server that manages the HMPs, one or more HMPs through which each client device has communicated, as the client device moves throughout the short-range wireless networking environment.

21. The method according to claim 1, further comprising the step of remembering, by a Handoff Core Server that manages the HMPs, which HMPs are currently operational.

22. The method according to claim 21, further comprising the step of providing one or more Application Programming Interfaces (APIs) through which the application programs may retrieve information about which HMPs are currently operational.

23. The method according to claim 22, wherein the Handoff Core Server also remembers a physical location of each currently-operational HMP, and wherein a selected one of the application programs invokes one of the APIs to retrieve information about whether a particular HMP is currently operational, and uses the retrieved information to provide location-based services whereby the particular HMP may be selected for the location-based services, based on the remembered physical location of the particular HMP, if the particular HMP is currently operational.

24. The method according to claim 23, wherein the selected application program provides proximity-based printing and the particular HMP is selected to perform a printing operation if the particular HMP is currently operational.

25. The method according to claim 22, wherein a selected one of the application programs invokes one of the APIs to retrieve information about whether a particular HMP is currently operational, and uses the retrieved information to provide personalized services whereby the particular HMP may be selected for the personalized services, based on whether the particular HMP is currently operational.

26. The method according to claim 21, wherein the remembering step further comprising the step of remembering when each of the currently-operational HMPs initially became operational.

27. The method according to claim 21, wherein the Handoff Core Server requires the HMPs to periodically notify the Handoff Core Server that they remain operational, and wherein the remembering step further comprises the step of remembering when the next periodic notification from each HMP is due.

28. The method according to claim 1, further comprising the steps of:

providing a plurality of Handoff Core Servers, each of which manages a subset of the plurality of HMPs; and

providing a Core Management Server to manage the Handoff Core Servers, wherein the Core Management Server can invoke requests to the Handoff Core Servers and wherein the Handoff Core Servers can invoke requests to the Core Management Server.

29. The method according to claim 1, further comprising the step of remembering, by a Handoff Core Server that manages the HMPs, a correspondence between the network address and the particular client device for which it was obtained, and wherein the handing off step uses this remembered correspondence.

30. The method according to claim 1, wherein the particular client device has a first link-level session with the first HMP before operation of the handing off step and a second link-level session with the second HMP after operation of the handing off step, whereby traffic sent from the particular client to the first HMP over the first link-level session is forwarded from the first HMP to a Handoff Core Server that manages the HMPs and traffic sent from the particular client to the second HMP over the second link-level session is forwarded from the second HMP to the Handoff Core Server, wherein the Handoff Core Server routes the forwarded traffic to its destination.

31. The method according to claim 30, further comprising the steps of:

receiving, at the Handoff Core Server, forwarded traffic sent from the particular client device over the link-level sessions; and

filtering the received traffic, by the Handoff Core Server, to determine whether or not to route the traffic to its destination.

32. The method according to claim 31, wherein the Handoff Core Server uses information from a policy file in the filtering step.

33. The method according to claim 1, wherein the making step further comprises the step of receiving, by the first HMP, traffic sent by the particular client device, and wherein the first HMP treats receipt of the traffic as an implicit connection establishment request.

34. The method according to claim 1, wherein the making step further comprises the step of receiving, by the first HMP, an explicit connection establishment request from the particular client device.

35. The method according to claim 34, wherein the explicit connection establishment request provides a link-level address of the particular client device.

36. The method according to claim 35, wherein the explicit connection establishment request also provides an identifier of a user who is using the particular client device.

37. The method according to claim 36, wherein the identifier of the user is validated through transmission of a Remote Authentication Dial In User Service (RADIUS) request from the first HMP.

38. The method according to claim 1, wherein the handing off step further comprises the step of receiving, by the second HMP, traffic sent by the particular client device, wherein the second HMP treats receipt of the traffic as an implicit connection establishment request.

39. The method according to claim 38, wherein the handing off step further comprises the step of receiving, by the first HMP, a connection termination request from the particular client device.

40. The method according to claim 38, wherein the handing off step further comprises the step of determining, by the first HMP, that no communication has been received from the particular client device for a certain length of time and thereby concluding that the particular client device is no longer communicating through the first HMP.

41. The method according to claim 1, wherein the handing off step further comprises the step of receiving, by the second HMP, an explicit connection establishment request from the particular client device.

42. The method according to claim 41, wherein the handing off step further comprises the step of receiving, by the first HMP, a connection termination request from the particular client device.

43. The method according to claim 41, wherein the handing off step further comprises the step of determining, by the first HMP, that no communication has been received from the particular client device for a certain length of time and thereby concluding that the particular client device is no longer communicating through the first HMP.

44. The method according to claim 1, wherein the network address is an Internet Protocol (IP) address.

45. The method according to claim 1, wherein the making step further comprises the step of receiving, by the first HMP, a communication from the particular the client device;

and wherein the obtaining step further comprises the steps of;

notifying a Handoff Core Server that manages the HMPs, by the first HMP responsive to the receiving step, of the particular client device; and

receiving by the first HMP, in response to the notifying step, the network address from the Handoff Core Server.