Method and apparatus for seamless mobility beween different access technologies

• US 20020191627A1
• Filed: 05/24/2001
• Published: 12/19/2002
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: Valtrus Innovations Limited (f/k/a Dolya Holdco 9 Limited) (Key Patent Innovations Limited)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Subbiah, Barani, Razavilar, Javad
• Granted Patent: US 6,826,154 B2
• Time in Patent Office: Days
• US Class Current: 370/428
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 48/17 Selecting a data network PoA [Point of Attachment]
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

The present invention includes a method and device to support hand off of a session between a mobile terminal and a server, while continuing the session. One aspect of the invention is a method involving a first entity having an IP stack and a second entity having an IP stack. These entities support a hand off from one access technology to another, wherein the different access technologies are differentiated by a characteristic such as their physical layer. Particular aspects of the present invention are described in the claims, specification and drawings.

Claims

1. A method of buffering and forwarding packets to support a hand off of a session between a mobile terminal and a server, the hand off involving a first entity having an IP stack and a second entity having an IP stack, including:

(a) receiving at a first entity having an IP stack, via a first access technology, a first message from a mobile terminal to stop sending and begin buffering session packets exchanged with a server;

acknowledging the first message;

(b) receiving at a second entity having an IP stack, via a second access technology, the second access technology utilizing a different physical layer than the first access technology, a second message from the mobile terminal directing the second entity to set up a new route between the mobile terminal and the server via the second entity;

acknowledging the second message;

signaling from the second entity to the first entity to start forwarding the buffered packets;

(c) receiving at the second entity the forwarded buffered packets;

relaying the forwarded buffered packets to the mobile terminal;

communicating to the server the new route; and

continuing the session between the mobile terminal and the server via the new route.

2. The method of claim 1, wherein the (c) receiving step and the communicating step are carried out in an order as listed.

3. The method of claim 1, wherein the (c) receiving step and the communicating step are carried out in an order different than listed.

4. The method of claim 1, wherein the (a) receiving step and the (b) receiving step are carried out in an order as listed.

5. The method of claim 1, wherein the (a) receiving step and the (b) receiving step are carried out in an order different than listed.

6. The method of claim 1, wherein the new route is via the second entity.

7. The method of claim 1, wherein the new route utilizes the second access technology.

8. The method of claim 1, wherein communicating the new route includes communicating a new IP address for the mobile terminal and an IP address for the second entity.

9. The method of claim 1, wherein communicating the new route includes a care-of for the mobile terminal.

10. The method of claim 9, the care-of address is an IP address of the second entity.

11. The method of claim 1, wherein the first message includes data elements for message type, message code, sequence number and error detection symbol.

12. The method of claim 11, wherein the error detection symbol is a checksum.

13. The method of claim 1, wherein the first message and the second message both include data elements for message type, message code, sequence number and error detection symbol.

14. The method of claim 13, wherein the error detection symbol is a checksum.

15. The method of claim 1, wherein the first access technology is compliant with any 802.11x standard.

16. The method of claim 1, wherein the first access technology includes using an unlicensed 2.4 GHz network.

17. The method of claim 1, wherein the first access technology is compliant with any Bluetooth standard.

18. The method of claim 1, wherein the first access technology includes using an RF connection compliant with any Bluetooth standard.

19. The method of claim 1, wherein the session is a TCP session.

20. The method of claim 1, wherein the session is a UDP session.

21. The method of claim 1, wherein the session is a WAP session.

22. The method of claim 1, wherein the session includes a Bluetooth standard compliant transport session.

23. The method of claim 1, wherein the connection via the second access technology is a PPP connection.

24. The method of claim 1, wherein the second access technology is compliant with an IS 95b standard.

25. The method of claim 1, wherein the second access technology is compliant with an enhanced GSM standard.

26. The method of claim 1, wherein the second access technology is compliant with a GPRS standard.

27. The method of claim 1, wherein the second access technology is compatible with access via Metricom.

28. The method of claim 1, wherein the second access technology utilizes a cellular telephone network.

29. The method of claim 1, wherein the second access technology utilizes an unlicensed 2.4 GHz network.

30. The method of claim 1, wherein the second access technology is made using communication between a satellite and the mobile terminal for at least one direction of the second access technology connection.

31. The method of claim 1, wherein the second access technology is compliant with any Bluetooth standard.

32. The method of claim 1, wherein the second access technology includes using an RF connection compliant with any Bluetooth standard.

33. The method of claim 1, further including buffering packets received at the second access router from the server until after completion of forwarding the buffered packets to the mobile terminal.

35. The method of claim 34, wherein the forwarding step and the communicating step are carried out in an order as listed.

36. The method of claim 34, wherein the forwarding step and the communicating step are carried out in an order different than listed.

37. The method of claim 34, wherein the (a) receiving step and the (b) receiving step are carried out in an order as listed.

38. The method of claim 34, wherein the (a) receiving step and the (b) receiving step are carried out in an order different than listed.

39. The method of claim 34, wherein the new route is via the second entity.

40. The method of claim 34, wherein the new route utilizes the second access technology.

41. The method of claim 34, wherein communicating the new route includes communicating a new IP address for the mobile terminal and an IP address for the second entity.

42. The method of claim 34, wherein communicating the new route includes a care-of for the mobile terminal.

43. The method of claim 42, the care-of address is an IP address of the second entity.

44. The method of claim 34, further including buffering packets received at the second access router from the server until after completion of forwarding the buffered packets to the mobile terminal.

46. The method of claim 45, wherein the (c) receiving step and the communicating step are carried out in an order as listed.

47. The method of claim 45, wherein the (c) receiving step and the communicating step are carried out in an order different than listed.

48. The method of claim 45, wherein the (a) receiving step and the (b) receiving step are carried out in an order different than listed.

49. The method of claim 45, wherein the new route is via the second entity.

50. The method of claim 45, wherein the new route utilizes the second access technology.

51. The method of claim 45, wherein communicating the new route includes communicating a new IP address for the mobile terminal and an IP address for the second entity.

52. The method of claim 45, wherein communicating the new route includes a care-of for the mobile terminal.

53. The method of claim 52, the care-of address is an IP address of the second entity.

54. The method of claim 45, the first message includes data elements for message type, message code, sequence number and error detection symbol.

55. The method of claim 54, wherein the error detection symbol is a checksum.

56. The method of claim 45, wherein the first message and the second message both include data elements for message type, message code, sequence number and error detection symbol.

57. The method of claim 56, wherein the error detection symbol is a checksum.

58. The method of claim 45, wherein the first access technology is compliant with any 802.11x standard.

59. The method of claim 45, wherein the first access technology includes using an unlicensed 2.4 GHz network.

60. The method of claim 45, wherein the first access technology is compliant with any Bluetooth standard.

61. The method of claim 45, wherein the first access technology includes using an RF connection compliant with any Bluetooth standard.

62. The method of claim 45, wherein the session is a TCP session.

63. The method of claim 45, wherein the session is a UDP session.

64. The method of claim 45, wherein the session is a WAP session.

65. The method of claim 45, wherein the session includes a Bluetooth standard compliant transport session.

66. The method of claim 45, wherein the connection via the second access technology is a PPP connection.

67. The method of claim 45, wherein the second access technology is compliant with an IS 95b standard.

68. The method of claim 45, wherein the second access technology is compliant with an enhanced GSM standard.

69. The method of claim 45, wherein the second access technology is compliant with a GPRS standard.

70. The method of claim 45, wherein the second access technology is compatible with access via Metricom.

71. The method of claim 45, wherein the second access technology utilizes a cellular telephone network.

72. The method of claim 45, wherein the second access technology utilizes an unlicensed 2.4 GHz network.

73. The method of claim 45, wherein the second access technology is made using communication between a satellite and the mobile terminal for at least one direction of the second access technology connection.

74. The method of claim 45, wherein the second access technology is compliant with any Bluetooth standard.

75. The method of claim 45, wherein the second access technology includes using an RF connection compliant with any Bluetooth standard.

76. The method of claim 45, further including buffering packets received at the second access router from the server until after completion of forwarding the buffered packets to the mobile terminal.

34. A method of buffering and forwarding packets to support a hand off of a session between a mobile terminal and a server, the hand off involving a first entity having an IP stack and a second entity having an IP stack, including:

(a) receiving at a first entity having an IP stack, via a first access technology, a first message from a mobile terminal to stop-sending and begin buffering session packets exchanged with a server;

acknowledging the first message;

(b) receiving at a second entity having an IP stack a second message to set up a new route from the mobile terminal to the server via a second access technology, the second access technology utilizing a different physical layer than the first access technology;

signaling from the second entity to the first entity to start forwarding the buffered packets;

forwarding the buffered packets from the first entity to the second entity and on to the mobile terminal;

communicating to the server the new route; and

continuing the session between the mobile terminal and the server via the second access technology.

45. A method of buffering and forwarding packets to support a hand off involving a first entity having an IP stack and a second entity having an IP stack, the first entity supporting communication with a mobile terminal via a first access technology, the second entity supporting communication with the mobile terminal via a second access technology and the mobile terminal engaged in a session with a server via the first access technology, the method including:

receiving at the second entity a message to set up a new route from the mobile terminal to a server via the second access technology, the second access technology utilizing a different physical layer than the first access technology;

communicating to the server the new route;

signaling from the second entity to the first entity to forward any buffered packets;

forwarding the buffered packets from the first entity to the second entity and on to the mobile terminal; and

continuing the session between the mobile terminal and the server via the second access technology.

77. A second entity having an IP stack adapted to accepting from a first entity having an IP stack a hand off between a first access technology and a second access technology of a session between a mobile terminal and a server, including:

a processor, having memory and resources, including an IP stack;

one or more communication ports, coupled with the processor, in communication with the first entity and in communication with the mobile terminal;

program storage memory, coupled with the processor, containing one or more programs adapted to;

(a) receiving at a first entity having an IP stack, via a first access technology, a first message from a mobile terminal to stop sending and begin buffering session packets exchanged with a server;

acknowledging the first message;

(b) receiving at a second entity having an IP stack, via a second access technology, the second access technology utilizing a different physical layer than the first access technology, a second message from the mobile terminal directing the second entity to set up a new route between the mobile terminal and the server via the second entity;

acknowledging the second message;

signaling from the second entity to the first entity to start forwarding the buffered packets;

(c) receiving at the second entity the forwarded buffered packets;

relaying the forwarded buffered packets to the mobile terminal;

communicating to the server the new route; and

continuing the session between the mobile terminal and the server via the new route.

78. A second entity having an IP stack adapted to accepting from a first entity having an IP stack a hand off between a first access technology and a second access technology of a session between a mobile terminal and a server, including:

a processor, having memory and resources, including an IP stack;

one or more communication ports, coupled with the processor, in communication with the first entity and in communication with the mobile terminal;

program storage memory, coupled with the processor, containing one or more programs adapted to;

(a) receiving at a first entity having an IP stack a first access technology a first message from a mobile terminal to stop sending and begin buffering session packets exchanged with a server;

acknowledging the first message;

(b) receiving at a second entity having an IP stack a second message to set up a route from the mobile terminal to the server via a second access technology, the second access technology utilizing a different physical layer than the first access technology;

signaling from the second entity to the first entity to start forwarding the buffered packets;

forwarding the buffered packets from the first entity to the second entity and on to the mobile terminal;

communicating to the server a care-of address for routing via the second access technology; and

continuing the session between the mobile terminal and the server via the second access technology.

79. A second entity having an IP stack adapted to accepting from a first entity having an IP stack a hand off between a first access technology and a second access technology of a session between a mobile terminal and a server, including:

a processor, having memory and resources, including an IP stack;

one or more communication ports, coupled with the processor, in communication with the first entity and in communication with the mobile terminal;

program storage memory, coupled with the processor, containing one or more programs adapted to;

receiving at the second entity a message to set up a new route from the mobile terminal to the server via the second access technology, the second access technology utilizing a different physical layer than the first access technology;

communicating to the server the new route;

signaling from the second entity to the first entity to forward any buffered packets;

forwarding the buffered packets from the first entity to the second entity and on to the mobile terminal; and

continuing the session between the mobile terminal and the server via the second access technology.

80. An entity having an IP stack, adapted to cooperating with an additional entity having an IP stack in a hand off of a session between a mobile terminal and a server, the entity including:

a processor, having memory and resources, the resources including an IP stack;

one or more communication ports, coupled with the processor and in communication with the mobile terminal, the server and the additional entity;

program storage memory, coupled with the processor, containing one or more programs, including logic segments to

(1) forward packets in the session between the mobile terminal and the server;

(2) stop forwarding the packets in the session and buffer the packets received from the server;

(3) forward the buffered packets to the additional entity;

(4) wait for a message to take over the session between the mobile terminal and the server; and

(5) communicate an address of the entity to the server with a binding update directive;

signal the additional entity to begin forwarding the buffered packets; and

forward the buffered packets received from the additional entity to the mobile terminal;

wherein the one or more programs transition among logic segments, including;

transitioning from logic segment (1) to logic segment (2) upon receiving a first message type from the mobile terminal;

transitioning from logic segment (2) to logic segment (3) upon receiving a second message type from the additional entity;

transitioning from logic segment (3) to logic segment (4) upon completing the forwarding of buffered packets to the additional entity;

transitioning from logic segment (4) to logic segment (1) upon receiving an initial message type from the mobile terminal;

transitioning from logic segment (4) to logic segment (5) upon receiving a third message type from the additional entity;

transitioning from logic segment (5) to logic segment (1) upon receiving a fourth message type from the additional entity indicating completion of forwarding of the buffered packets.

81. The device of claim 80, wherein state (4) is treated as two states (4a) and (4b);

the transition to state (1) proceeds from state (4a); and

the transition to state (5) proceeds from state (4b).

82. The device of claim 80, wherein logic segment (5) carries out actions in an order as listed.

83. The device of claim 80, wherein logic segment (5) carries out actions in an order different than listed.

84. The device of claim 80, wherein:

logic segment (5) further includes temporarily buffering any packets received from the server while forwarding the buffered packets received from the additional entity to the mobile terminal; and

transitioning from logic segment (5) to logic segment (1) further includes forwarding to the mobile terminal the temporarily buffered packets received from the server upon receiving the fourth message type from the additional entity.