Method and apparatus for providing mobile and other intermittent connectivity in a computing environment

• US 6,546,425 B1
• Filed: 06/11/1999
• Issued: 04/08/2003
• Est. Priority Date: 10/09/1998
• Status: Expired due to Term

• Current Assignee: Netmotion Wireless Holdings, Inc. (NetMotion Software, Inc.)
• Original Assignee: Netmotion Wireless Incorporated
• Inventors: Sturniolo, Emil A., Menn, Anatoly, Hanson, Aaron D., Savarese, Joseph T., Olson, Erik D.
• Primary Examiner(s): Geckil, Mehmet B.
• Application Number:
  US09/330,310
• Time in Patent Office: 1,397 Days
• Field of Search: 709/245, 709/250, 709/330, 709/229, 709/228, 709/227, 709/230, 709/203, 709/220, 709/221, 709/202
• US Class Current: 709/227
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 67/133 Protocols for remote procedure calls [RPC]
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• CPC Class Codes: H04L 67/59 Providing operational support to end devices by off-loading in the network or by emulation, e.g. when they are unavailable
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 8/02 Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 80/10 adapted for application session management, e.g. SIP [Session Initiation Protocol] connection management H04W76/00; arrangements for session management H04L67/14
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy

Abstract

A seamless solution transparently addresses the characteristics of nomadic systems, and enables existing network applications to run reliably in mobile environments. The solution extends the enterprise network, letting network managers provide mobile users with easy access to the same applications as stationary users without sacrificing reliability or centralized management. The solution combines advantages of existing wire-line network standards with emerging mobile standards to create a solution that works with existing network applications. A Mobility Management Server coupled to the mobile network maintains the state of each of any number of Mobile End Systems and handles the complex session management required to maintain persistent connections to the network and to other peer processes. If a Mobile End System becomes unreachable, suspends, or changes network address (e.g., due to roaming from one network interconnect to another), the Mobility Management Server maintains the connection to the associated peer task—allowing the Mobile End System to maintain a continuous connection even though it may temporarily lose contact with its network medium. In one example, Mobility Management Server communicates with Mobile End Systems using Remote Procedure Call and Internet Mobility Protocols.

Claims

1. In a mobile computing network including at least one peer computing system and at least one mobile computing device coupled to the network via a link, an improvement comprising a server coupled to the network, said server having a transport protocol engine that provides at least one transport protocol for communicating via the network, said server proxying communications between the mobile computing device and the peer computing system so as to maintain a continuous data communication session between the mobile computing device and the peer computing system during times when the link is temporarily interrupted, said server proxying said communications transparently to said server transport protocol engine and said peer computing system.

2. A network as in claim 1 wherein said mobile computing device has a point-of-presence address on said network, said peer computing system communicates with said server using a virtual address, and said server maps said virtual address to said point-of-presence address.

3. A network as in claim 2 wherein said server detects when said mobile computing device has changed its point-of-presence address, and re-maps said virtual address to said changed point-of-presence address.

4. A network as in claim 1 wherein said server queues and responds to requests from said peer computing system on behalf of said mobile computing device even during times when said mobile computing device is temporarily unreachable or roaming.

5. A network as in claim 1 wherein said server communicates with said mobile computing device using a conventional transport protocol.

6. A network as in claim 5 wherein said server communicates with said mobile computing device using remote procedure calls.

7. A network as in claim 5 wherein said server communicates with said mobile computing device using an Internet Mobility Protocol.

8. A network as in claim 7 wherein said Internet Mobility Protocol provides for automatic removal of datagrams based on configurable timeouts.

9. A network as in claim 7 wherein said Internet Mobility Protocol provides for automatic removal of datagrams based on configurable retries.

10. A network as in claim 1 wherein said server performs global, device-group, device-specific, user-group, and/or per-user policy management of consumption of network resources by said mobile computing device.

11. A network as in claim 1 wherein said server provides a configurable session priority for said session.

12. A network as in claim 1 wherein said mobile network includes plural sub-networks, and said mobile computing device uses the Dynamic Host Configuration Protocol along with other methodologies to detect that said mobile computing device has roamed from one of said plural sub-networks to another of said plural sub-networks.

13. A network as in claim 1 wherein said server comprises a Mobility Management Server.

14. A network as in claim 1 further including at least one mobile interconnect coupling said mobile computing devices to said server.

15. The network of claim 1 wherein said server includes a transport interface interfacing with said transport protocol engine, and wherein said proxying is transparently performed at said transport interface.

16. The network of claim 1 wherein the network includes sub-networks, and the server maintains said session even when said mobile computing device roams between sub-networks.

17. The network of claim 1 wherein the network includes plural sub-networks, and the server detects when said mobile computing device has roamed between said plural sub-networks.

18. The network of claim 1 wherein said transport protocol uses addressing to route data to destinations, and said proxying translates selected network addresses to maintain said session between said mobile computing device and said peer computing system even when said mobile computing device temporarily becomes unavailable.

19. The network of claim 1 wherein the session includes plural communication sources and destinations.

20. The network of claim 19 wherein the server provides different priorities for said plural communication sources and destinations.

21. A method of maintaining a persistent session with at least one mobile computing device in a mobile computing environment despite intermittent connections, said mobile computing device permitting execution of at least one networked application that is not designed especially for said mobile computing environment, said mobile computing device including an application network interface that interfaces with said application, said mobile computing device further including a transport interface existing between a transport protocol engine and at least said application, said transport interface interfacing with said transport protocol engine, said method including:

managing, at said transport interface, at least one session between said mobile computing device and at least one further computing device in a manner that is transparent to both said transport protocol engine and said application, and

maintaining the session even when the mobile computing device becomes unreachable, suspends or changes network address.

22. A method as in claim 21 further including providing at least one configurable session priority for said session.

23. A method as in claim 21 wherein said managing step includes managing consumption of network resources by said mobile computing device.

24. A method as in claim 21 wherein the mobile computing environment includes plural sub-networks, and said maintaining step uses Dynamic Host Configuration Protocol along with other methodologies to detect when said mobile computing device roams between said sub-networks.

25. A method as in claim 21 wherein said managing step communicates datagrams with said mobile computing device and allows automatic removal of unreliable ones of said datagrams based on at least one configurable parameter.

26. A method as in claim 25 wherein said configurable parameter comprises a timeout.

27. A method as in claim 25 wherein said configurable parameter comprises a retry number.

28. A method as in claim 21 further including allowing said mobile computing device to obtain a variable point of presence address, and wherein said managing step includes mapping said variable point of presence address to a virtual address.

29. A method as in claim 21 wherein said managing step includes using a Remote Procedure Call protocol to communicate with the mobile computing device.

30. A method as in claim 21 wherein said maintaining step maintains the connection state of said session during interruptions in at least one link connecting said mobile computing device with said mobile computing environment.

31. A method as in claim 21 wherein said managing step includes communicating with at least one communications peer in said mobile computing environment using at least one transport protocol generated by said transport protocol engine.

32. A method as in claim 21 wherein said mobile computing device includes plural communication sources, and said managing step includes coalescing data from said plural communication sources destined for multiple destinations into a stream, and forwarding said stream.

33. A method as in claim 32 further including demultiplexing said coalesced data from said stream and forwarding said demultiplexed data to plural communications destinations.

34. A method as in claim 32 wherein said stream includes frames, and said coalescing includes dynamically resizing said frames to accommodate a maximum and/or optimum transmission unit of the mobile computing environment.

35. A method as in claim 32 wherein said coalescing includes maintaining semantics of unreliable data, and selectively discarding said unreliable data based on said semantics.

36. A method as in claim 21 wherein said managing step includes providing guaranteed delivery of messages to and/or from said mobile computing device.

37. A method as in claim 21 wherein said managing step includes controlling which network resources are accessible by said mobile computing device.

38. The method of claim 21 wherein said mobile computing environment includes plural sub-networks, and said maintaining step maintains said session even when said mobile computing device roams between said plural sub-networks.

39. A server for maintaining a persistent connection with at least one mobile computing device in a mobile computing environment including at least one further computing peer, said mobile computing device executing at least one communication source or destination, said server having a transport protocol engine providing a server transport protocol, said server including:

a session manager that manages at least one session between said mobile computing device and said at least one further communications peer, said session manager maintaining the session even when the mobile computing device becomes unreachable, or changes network address in a manner that is transparent to the mobile computing device communication source or destination, the communications peer, and said server transport protocol.

40. A server as in claim 39 wherein said session manager includes a session priority queue that provides at least one configurable session priority for said session.

41. A server as in claim 39 wherein said session manager includes means for managing consumption of network resources by said mobile computing device.

42. A server as in claim 39 wherein the mobile computing environment includes plural sub-networks, and said session manager transparently maintains the session even when said mobile computing device roams between said sub-networks.

43. A server as in claim 39 wherein said session manager communicates datagrams with said mobile computing device and automatically removes unreliable ones of said datagrams based on at least one configurable parameter.

44. A server as in claim 43 wherein said configurable parameter comprises a timeout.

45. A server as in claim 43 wherein said configurable parameter comprises a retry number.

46. A server as in claim 39 wherein said mobile computing environment provides said mobile computing device with a variable point of presence address, and said session manager maps said variable point of presence address to a virtual address.

47. A server as in claim 39 wherein said session manager uses a Remote Procedure Call protocol to communicate with the mobile computing device.

48. A server as in claim 39 wherein said mobile computing environment includes at least one link connecting said mobile computing device with said mobile computing environment, and said session manager maintains the connection state of said session even during interruptions in said link.

49. A server as in claim 39 wherein session manager communicates with said mobile computing device using at least one transport protocol.

50. A server as in claim 39 wherein said mobile computing device includes plural application sources, and said session manager coalesces data associated with said plural application sources into a stream, and forwards said stream.

51. A server as in claim 39 wherein said mobile computing device includes plural application sources, and said session manager demultiplexes coalesced data from said plural application sources and forwards said demultiplexed data to plural associated destinations.

52. A server as in claim 39 wherein session manager communicates with said mobile computing device using frames, and dynamically resizes said frames to accommodate a maximum or optimum transmission unit of the mobile computing environment.

53. A server as in claim 39 wherein said session manager maintains semantics of unreliable data, and selectively discards said unreliable data based on said semantics.

54. A server as in claim 39 wherein said session manager provides for guaranteed delivery of messages to and/or from said mobile computing device.

55. A server as in claim 39 wherein said session manager places controls on mobile computing environment resources said mobile computing device can access.

56. The server of claim 39 wherein said server includes a transport interface interfacing with said transport protocol engine, said session manager operating at said transport interface.

57. The server of claim 39 wherein said mobile computing environment includes networks or sub-networks, and said session manager detects when the mobile computing device has roamed between networks or sub-networks.

58. The server of claim 39 wherein the server communicates with said mobile computing device and said further computing peer using network addresses, and said session manager provides for a consistent network address destination for said further peer to communicate with even in the event said mobile computing device changes address or temporarily becomes unreachable, said server transport protocol responding to messages from said further computing peer directed to said consistent network address destination to keep said data communications active even in the event said mobile computing device is unable to respond.

59. In a mobile computing environment including a proxy server, a mobile computing device that maintains a persistent virtual connection with at least one further computing device during times when the mobile computing device becomes unreachable, suspends or changes network address, said mobile computing device permitting execution of at least one networked application that is not designed especially for said mobile computing environment, said mobile computing device including an application network interface that interfaces with said application, said mobile computing device further including a transport protocol engine, said mobile computing device including:

a transport interface existing between said transport protocol engine and at least said application, said transport interface interfacing with said transport protocol engine, and

a mobile interceptor coupled to said transport interface, said mobile interceptor intercepting, transparently to said application, requests for network services at said transport interface, generating Remote Procedure Calls responsive to said requests for network services, and forwarding said Remote Procedure Calls to said proxy server.

60. A mobile computing device as in claim 59 wherein said mobile interceptor includes a session priority queue that provides at least one configurable session priority.

61. A mobile computing device as in claim 59 wherein said mobile interceptor includes means for managing consumption of network resources by said mobile computing device.

62. A mobile computing device as in claim 59 wherein the mobile computing environment includes plural sub-networks, and the mobile computing device further includes means for using Dynamic Host Configuration Protocol along with other methodologies to detect when said mobile computing device roams between said sub-networks and obtain a point of presence address.

63. A mobile computing device as in claim 59 wherein said mobile interceptor communicates datagrams with proxy server and automatically removes unreliable ones of said datagrams based on at least one configurable parameter.

64. A mobile computing device as in claim 63 wherein said configurable parameter comprises a timeout.

65. A mobile computing device as in claim 63 wherein said configurable parameter comprises a retry number.

66. A mobile computing device as in claim 59 wherein said mobile computing device has an associated a variable point of presence address that said proxy server maps to a virtual address.

67. A mobile computing device as in claim 59 wherein said mobile interceptor uses a Remote Procedure Call protocol to communicate with the said proxy server.

68. A mobile computing device as in claim 59 wherein said mobile computing environment includes at least one link connecting said mobile computing device with said mobile computing environment, and said mobile interceptor exchanges updated connection state information of at least one session with said proxy server even after an interruption in said link.

69. A mobile computing device as in claim 59 wherein said mobile computing device includes a transport protocol handler, and said mobile interceptor communicates with said proxy server via said transport protocol handler.

70. A mobile computing device as in claim 59 wherein said mobile computing device includes plural application sources, and said mobile interceptor coalesces data associated with said plural application sources into a stream, and forwards said stream to said proxy server.

71. A mobile computing device as in claim 59 wherein said mobile computing device includes plural application destinations, mobile interceptor demultiplexes coalesced data from plural application sources and forwards said demultiplexed data to said plural application destinations.

72. A mobile computing device as in claim 59 wherein mobile interceptor communicates with said proxy server using frames, and dynamically resizes said frames to accommodate a maximum or optimum transmission unit of the mobile computing environment.

73. A mobile computing device as in claim 59 wherein said mobile interceptor maintains semantics of unreliable data, and selectively discards said unreliable data based on said semantics.

74. A mobile computing device as in claim 59 wherein said mobile interceptor provides for guaranteed delivery of messages to and/or from said proxy server.

75. A mobile computing device as in claim 59 wherein said mobile interceptor places controls on mobile computing environment resources said mobile computing device can access.

76. The mobile computing environment of claim 59 wherein said mobile computing environment includes plural networks or sub-networks, and said interceptor maintains the session even when said mobile computing device roams between said plural networks or sub-networks.