Method for seamless networking support for mobile devices using serial communications

• US 6,651,105 B1
• Filed: 11/12/1999
• Issued: 11/18/2003
• Est. Priority Date: 11/12/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bisdikian, Chatschik, Naghshineh, Mahmoud, Bhagwat, Pravin, Korpeoglu, Ibrahim
• Primary Examiner(s): El-Hady, Nabil
• Assistant Examiner(s): Chang, Jungwon
• Application Number:
  US09/439,952
• Time in Patent Office: 1,467 Days
• Field of Search: 709/245, 709/217, 709/223, 709/236, 709/219, 709/239, 709/227, 375/225, 370/338, 370/400, 370/401, 370/349, 455/432
• US Class Current: 709/239
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/168 specially adapted for link layer protocols, e.g. asynchronous transfer mode [ATM], synchronous optical network [SONET] or point-to-point protocol [PPP]
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/323 in the physical layer [OSI layer 1]
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 69/325 in the network layer [OSI layer 3], e.g. X.25 H04L69/16 takes precedence
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

The present invention provides a method, apparatus and computer product for a mobile device to roam securely and seamlessly from one access point to another access point without disrupting an active PPP connection. The method includes establishing, maintaining, and terminating a PPP connection between a mobile device and a PPP server via an access point, wherein the mobile device is equipped with a serial asynchronous communication interface. The PPP server is attached to a packet switched data network, and the access point is acting as a bridge between the serial communication interface and the packet switched communication interface. Also provided is a method to emulate a direct RS-232 cable connection between a mobile device and another computer located several hops away from the mobile device. It provides a method of keeping the RS-232 cable emulation between the mobile device an another computer system intact despite changes in mobile device'"'"'s location in the network. It also provides a method of exchanging cookies between peers at the PPP connection establishment time and using them for fast reauthentication. This is a secure method of switching from one PPP proxy to another PPP proxy without disrupting the end to end PPP connection.

Claims

1. A method comprising:

establishing a PPP connection between a mobile device and a PPP server via an access point, wherein the mobile device is equipped with a serial asynchronous communication interface, the PPP server is attached to a packet switched data network via a packet switched communication interface, and the access point is acting as a bridge between the serial asynchronous communication interface and the packet switched communication interface, by;

receiving a PPP connection establishment frame at the access point from the mobile device over the serial asynchronous communication interface;

establishing a bi-directional network layer tunnel between the access point and the PPP server over the packet switched data network;

forwarding the PPP connection establishment frame to the PPP server over the biderectional network layer tunnel; and

maintaining the flow of PPP frames between the PPP server and the device via the access point by forwarding PPP frames received from the mobile device to the PPP server over the bi-directional network layer tunnel, and forwarding the PPP frames received from the PPP server over the bi-directional network layer tunnel to the mobile device over the serial asynchronous communication interface.

2. A method as recited in claim 1, wherein a service level of the bi-directional network layer tunnel is adjusted based on a mode in which a PPP protocol is used.

3. A method as recited in claim 1, wherein the serial asynchronous communication interface is RS-232.

4. A method as recited in claim 3, where the RS-232 interface is provided on top of a packet oriented wireless MAC layer.

5. A method as recited in claim 1, wherein the step of establishing the bi-directional network layer tunnel is started after receiving a PPP LCP Configure request frame from the mobile device.

6. A method as recited in claim 1, wherein the access point also acts as a PPP proxy and the step of establishing the bi-directional network layer tunnel is started after completing a PPP LCP negotiation with the access point.

7. A method as recited in claim 1, further comprising terminating the bi-directional network layer tunnel between the access point and the PPP server after the completion of the PPP connection.

8. A method as recited in claim 7, wherein the step of terminating is started after the transmission of a LCP Term-Req ack message.

9. A method comprising:

establishing a connection between a mobile device and a server via an access point, wherein the mobile device is equipped with a serial asynchronous communication interface, the server is attached to a packet switched data network via a packet switched communication interface, and the access point is acting as a bridge between the serial asynchronous communication interface and the packet switched communication interface, by;

receiving a connection establishment frame at the access point from the mobile device over the serial asynchronous communication interface;

establishing a bi-directional network layer tunnel between the access point and the server over the packet switched data network;

forwarding the connection establishment frame to the server over the bi-directional network layer tunnel; and

maintaining the flow of frames between the server and the mobile device via the access point by forwarding frames received from the mobile device to the server over the bi-directional network layer tunnel, and forwarding the frames received from the server over the bi-directional network layer tunnel to the mobile device over the serial asynchronous communication interface.

10. A method as recited in claim 9, wherein the connection employs a PPP protocol.

11. An article of manufacture comprising a computer usable medium having computer readable program code means embodied therein for causing establishment of a connection between a mobile device and a server via an access point, wherein the mobile device is equipped with a serial asynchronous communication interface, the server is attached to a packet switched data network, and the access point is acting as a bridge between the serial asynchronous communication interface and the packet switched communication interface, the computer readable program code means in said article of manufacture comprising computer readable program code means for causing a computer to effect:

receiving a connection establishment frame at the access point from the mobile device over the serial asynchronous communication interface;

establishing a bi-directional network layer tunnel between the access point and the server over the packet switched data network;

forwarding the connection establishment frame to the server over the bi-directional network layer tunnel; and

maintaining the flow of frames between the server and the mobile device via the access point by forwarding frames received from the mobile device to the server over the bi-directional network layer tunnel, and forwarding the frames received from the server over the bi-directional network layer tunnel to the mobile device over the serial asynchronous communication interface.

12. An article of manufacture as recited in claim 11, wherein the access point also acts as a PPP proxy and the step of establishing the bi-directional network layer tunnel is started after completing a PPP LCP negotiation with the access point.