Method and apparatus for providing mobile and other intermittent connectivity in a computing environment
View Patent ↗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.
1. A method for enabling secure data communication with a computing device that roams among plural data communication networks or subnetworks of the type that carry Internet Protocol (IP) data, said method comprising:
establishing access to at least one data communications network or subnetwork carrying IP data;
using said network or subnetwork to institute secure data communications between said computing device and another computing device;
upon said computing device roaming while operational to a further network or subnetwork carrying IP data, establishing access at the computing device with said further network or subnetwork to enable said computing device to communicate over said further network or subnetwork;
participating in a DHCP process with said further network or subnetwork;
learning, at least in part in response to said DHCP process, that said computing device is enabled to communicate over said further network or subnetwork;
based at least in part on said learning, informing said another computing device that said computing device has roamed and has access to said further network or subnetwork; and
using said access to said further network or subnetwork to continue said secure data communications between the computing device and said another computing device.
2. The method of claim 1 wherein said computing device comprises a mobile computing device that communicates wirelessly with said at least one data communications network or subnetwork and said further network or subnetwork.
3. The method of claim 1 wherein said another computing device comprises an intermediary computing device.
4. The method of claim 1 wherein said another computing device comprises a server.
5. The method of claim 1 wherein said another computing device comprises a proxy server.
6. The method of claim 1 wherein the at least one data communications network or subnet carrying IP data and the further data communications network or subnet carrying IP data provide a homogeneous collection of link layer data communication networks or subnetworks.
7. The method of claim 1 wherein the at least one data communications network or subnet carrying IP data and the further data communications network or subnet carrying IP data provide a heterogeneous collection of link layer data communication networks or subnetworks.
8. The method of claim 1 wherein said participating includes sending a discover message.
9. The method of claim 1 wherein said learning compares a network address dynamically provided by DHCP with a previously-used network address, and determines whether said addresses are different.
10. The method of claim 1 wherein said computing device performs said participation, said DHCP process dynamically provides a network address to said computing device, and said method further includes using said dynamically-provided network address to continue said secure communications via said further network or subnetwork.
11. The method of claim 1 wherein said learning includes detecting, based on a network address that is dynamically provided by said DHCP process, that said computing device's network point of attachment has changed.
12. The method of claim 1 further including authenticating or reauthenticating said continued secure communications in response to learning said computing device has roamed.
13. The method of claim 1 wherein said data communications network or subnetwork is wireless, and said further data communications network or subnetwork is non-wireless.
14. The method of claim 1 wherein said data communications network or subnetwork is non-wireless, and said further data communications network or subnetwork is wireless.
15. The method of claim 1 wherein said computing device supports at least one application layer session, and said roaming allows said application layer session to continue without terminating.
16. The method of claim 1 further including changing routing information for said secure communications to continue.
17. The method of claim 1 further including intercepting calls at the transport driver interface.
18. The method of claim 1 further including intercepting calls at the socket API level.
19. The method of claim 1 further including establishing said secure communications with said computing device using UDP.
20. The method of claim 1 further including issuing a ping check to determine if the computing device temporarily lost and then regained contact with a sub-network, but has not roamed to a different sub-network.
21. The method of claim 1 wherein said computing device comprises a laptop computer with a display, a keyboard and a wireless interface.
22. The method of claim 1 wherein said computing device comprises a mobile medical computing device.
23. The method of claim 1 further including providing configurable session priorities for said computing device and/or users thereof.
24. The method of claim 1 wherein the point of presence address of said computing device changes during roaming, and wherein said method further includes maintaining a constant virtual address associated with said computing device at least during roaming.
25. The method of claim 1 wherein said computing device moves from one type of connection to another during roaming.
26. The method of claim 1 wherein said computing device connects to said network or subnetwork and to said further network or subnetwork using different network interfaces.
27. A method, performed by a computing device while the computing device is operational, for enabling secure data communication over at least one data communication network or subnetwork of the type that carries Internet Protocol (IP) data, said method comprising:
establishing access to at least one data communications network or subnetwork carrying IP data;
using said network or subnetwork access to establish secure data communications with another computing device;
disassociating access from said network or subnetwork;
subsequent to said disassociating step, reestablishing access to said network or subnetwork;
participating in a DHCP process with said network or subnetwork;
learning, at least in part in response to said DHCP process, that said computing device has reestablished access to said network or subnetwork;
based at least in part on said learning, informing said another computing device of said reestablished access; and
using said reestablished access to continue said secure data communications with said another computing device.
28. The method of claim 27 wherein said computing device comprises a mobile computing device that communicates wirelessly with said at least one data communications network or subnetwork carrying IP data.
29. The method of claim 27 wherein said another computing device comprises an intermediary computing device.
30. The method of claim 27 wherein said another computing device comprises a server.
31. The method of claim 27 wherein said another computing device comprises a proxy server.
32. The method of claim 27 wherein the at least one data communications network or subnet carrying IP data comprises a homogeneous collection of link layer data communication networks or subnetworks.
33. The method of claim 27 wherein the at least one data communications network or subnet carrying IP data comprises a heterogeneous collection of link layer data communication networks or subnetworks.
34. The method of claim 27 wherein said participating includes sending a discover message.
35. The method of claim 27 wherein said learning compares a network address dynamically provided by DHCP with a previously-used network address, and determines whether said addresses are different.
36. The method of claim 27 wherein said computing device performs said participation, said DHCP process dynamically supplies a network address to said computing device, and said method further includes using said dynamically supplied network address to continue said secure data communications.
37. The method of claim 27 wherein said learning includes detecting, based on a network address that is dynamically provided by said DHCP process, that a network point of attachment has not changed.
38. The method of claim 27 further including authenticating or reauthenticating said continued secure data communications.
39. The method of claim 27 wherein said data communications network or subnetwork is wireless.
40. The method of claim 27 wherein said data communications network or subnetwork is non-wireless.
41. The method of claim 27 wherein said computing device supports at least one application layer session, and said disassociating does not cause said application layer session to terminate.
42. The method of claim 27 further including intercepting calls at the transport driver interface.
43. The method of claim 27 further including intercepting calls at the socket API level.
44. The method of claim 27 further including establishing said secure data communications using UDP.
45. The method of claim 27 further including issuing a ping check to determine if the computing device temporarily lost and then regained contact with a sub-network, but has not roamed to a different sub-network.
46. The method of claim 27 wherein said computing device comprises a laptop computer with a display, a keyboard and a wireless interface.
47. The method of claim 27 wherein said computing device comprises a mobile medical computing device.
48. The method of claim 27 further including providing configurable session priorities for said computing device and/or users thereof.
49. The method of claim 27 wherein the point of presence address of said computing device changes during roaming, and wherein said method further including maintaining a virtual address associated with said computing device constant at least during roaming.
50. The method of claim 27 wherein said computing device moves from one type of connection to another on said network or subnetwork.
51. The method of claim 27 wherein said computing device can connect to said network or subnetwork using plural different network interfaces.
52. A method for allowing a mobile computing device to move between plural IP-based networks, comprising:
connecting the mobile computing device to at least one network;
using a dynamically-supplied IP address to enable secure data communications providing application and/or transport layer sessions between said mobile computing device and another computing device;
then migrating the mobile computing device to a further network while said mobile computing device is operational;
determining, based at least in part on a DHCP process performed on said further network, that said mobile computing device may have moved; and
in response to said determining, taking further action to continue said secure data communications including said application and/or transport layer sessions between said moved mobile computing device and said another computing device over said further network without terminating said application and/or transport layer sessions.
53. A method for allowing a mobile computing device to roam across IP-based networks, comprising:
connecting the mobile computing device to at least one network medium used for data communications;
using a network layer address to facilitate secure IP-based data communications including application and/or transport layer sessions between said mobile computing device and another computing device at least in part via said network medium;
then connecting the mobile computing device to a further network medium without first rebooting said mobile computing device;
performing a DHCP process over said further network medium;
discovering, based at least in part on said DHCP process, that said mobile computing device has roamed; and
based at least in part on said discovering, using a further network layer address to continue said secure IP-based data communications between said mobile computing device and said another computing device without terminating application and transport layer sessions therebetween.
54. A system for enabling secure data communication comprising:
plural data communication networks or subnetworks of the type that carry Internet Protocol (IP) data;
a mobile computing device that, while operational, roams among said plural data communication networks or subnetworks; and
another computing device that communicates with said mobile computing device via said plural data communications networks or subnetworks,
wherein said mobile computing device comprises:
at least one wireless data communications device for establishing access to said at least one data communications network or subnetwork carrying IP data and for using said network or subnetwork to institute secure wireless data communications with said another computing device, and upon said mobile computing device wirelessly roaming while operational to a further network or subnetwork carrying IP data, for establishing access with said further network or subnetwork to enable said mobile computing device to communicate over said further network or subnetwork,
a listener that participates in a DHCP process with said further network or subnetwork;
a detector coupled to said listener, said detector learning, at least in part in response to said DHCP process, that said mobile computing device is enabled to communicate over said further network or subnetwork and, based at least in part on said learning, using said access to said further network or subnetwork to continue said secure data communications between the mobile computing device and said another computing device.
55. A computing device comprising:
data communicators that establishes access to at least one data communications network or subnetwork carrying Internet Protocol (IP) data over at least one data communication network or subnetwork, and which uses said access to said network or subnetwork to establish secure data communications with another computing device;
a DHCP listener that participates in a DHCP process with said network or subnetwork upon said computing device disassociating access from said network or subnetwork and then reestablishing access to said network or subnetwork, said DHCP listener learning, at least in part in response to said DHCP process, that said computing device has reestablished access to said network or subnetwork;
wherein said data communicator informs said another computing device, based at least in part on said learning, of said reestablished access and uses said reestablished access to continue said secure data communications with said another computing device.