Mobile point-to-point protocol

• US 6,496,491 B2
• Filed: 09/09/1998
• Issued: 12/17/2002
• Est. Priority Date: 05/08/1998
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Rai, Girish, Chuah, Mooi Choo
• Primary Examiner(s): Nguyen, Steven
• Assistant Examiner(s): Nguyen, Phuongchau Ba
• Application Number:
  US09/150,403
• Publication Number:
  US 20020006132A1
• Time in Patent Office: 1,560 Days
• Field of Search: 370/389, 370/401, 370/402, 370/403, 370/404, 370/352, 370/354, 370/355, 370/356, 370/331, 370/338
• US Class Current: 370/331
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 63/0272 Virtual private networks
• 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 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 4/12 Messaging; Mailboxes; Announcements
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 76/22 Manipulation of transport tunnels
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/14 Backbone network devices

Abstract

Apparatus for transferring packet data incorporates a “hand-off” feature that allows the transfer of an existing PPP connection from one packet server to another packet server. Such a hand-off control message or call continue transaction can be initiated by any of the servers involved in the transactions. For instance, assume an initial arrangement where a point-to-point call is set up and in progress between a user and a private network via a first packet server (e.g., a first Serving LAC) and a second packet server (e.g., an Anchor LAC). If, for example, the user moves out of the region served by the first packet server into a region served by a third packet server (e.g., a second Serving LAC), then a hand-off control message transaction, according to the invention, is initiated. Either the second Serving LAC or the Anchor LAC may initiate the call continue transaction. Alternatively, radius servers respectively associated with the packet servers may be employed to perform the call continue transaction. Furthermore, assuming that a communication path is not yet established between the second packet server (e.g., Anchor LAC) and the third packet server (e.g., the second Serving LAC), a communication path (e.g., tunnel) set-up control message transaction may be performed concurrent with the call continue transaction. Still further, at least one packet server (e.g., the Anchor LAC) monitors state variables associated with the packet servers (e.g., the second Serving LAC and the private network) from which it receives packet data.

Claims

1. Apparatus comprising:

packet equipment which is configured to participate in a communication session through a point-to-point protocol (PPP) connection with a first packet server and a second packet server established in accordance with a tunneling protocol and to monitor sequence number state variables associated with packet data transmitted between the first packet server and the second packet server so as to maintain the communication session, including packet order, in the presence of a change in the PPP connection without a need to reestablish the PPP connection.

2. The apparatus of claim 1, wherein the packet equipment stores a state variable set including a predetermined number of state variables wherein one half of the state variables are associated with the first packet server and the other half of the state variables are associated with the second packet server.

3. The apparatus of claim 1, wherein the first packet server is a private network.

4. The apparatus of claim 3, wherein the second packet server is coupled to a source such that a multi-hop communication path is established between the source and the private network.

7. The apparatus of claim 1, wherein the change in the PPP connection includes the removal of the second packet server.

8. The apparatus of claim 1, wherein the change in the PPP connection includes the replacement of the second packet server with a third packet server.

5. A method for use in a packet server comprising the steps of:

establishing a communication session through a point-to-point protocol (PPP) connection with a first packet server and a second packet server in accordance with a tunneling protocol; and

monitoring sequence number state variables associated with packet data transmitted between the first packet server and the second packet server so as to maintain the communication session, including packet order, in the presence of a change in the PPP connection without a need to reestablish the PPP connection.

6. The method of claim 5, further comprising the step of storing a state variable set including a predetermined number of state variables wherein one half of the state variables are associated with the first packet server and the other half of the state variables are associated with the second packet server.

9. The method of claim 5, wherein the change in the PPP connection includes the removal of the second packet server.

10. The method of claim 5, wherein the change in the PPP connection includes the replacement of the second packet server with a third packet server.

11. Apparatus comprising:

packet equipment which is configured to participate in a communication session through a point-to-point protocol (PPP) connection with a source and at least one packet server established in accordance with a tunneling protocol and to monitor sequence number state variables associated with packet data transmitted between itself and the at least one packet server so as to maintain the communication session, including packet order, in the presence of a change in the PPP connection without a need to reestablish the PPP connection.

12. The apparatus of claim 11, wherein the change in the PPP connection includes the addition of a second packet server between the source and the packet equipment.

13. A method for use in a packet server comprising the steps of:

establishing a communication session through a point-to-point protocol (PPP) connection with a source and at least one packet server in accordance with a tunneling protocol; and

monitoring sequence number state variables associated with packet data transmitted between itself and the at least one packet server so as to maintain the communication session, including packet order, in the presence of a change in the PPP connection without a need to reestablish the PPP connection.

14. The apparatus of claim 13, wherein the change in the PPP connection includes the addition of a second packet server between the source and the packet equipment.