Virtual dial-up protocol for network communication

• US 8,194,654 B1
• Filed: 05/06/2004
• Issued: 06/05/2012
• Est. Priority Date: 07/29/1996
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Valencia, Andrew J.
• Primary Examiner(s): Matar, Ahmad
• Assistant Examiner(s): Gay, Sonia
• Application Number:
  US10/841,789
• Time in Patent Office: 2,952 Days
• Field of Search: 370/389, 370352-356, 370/420, 370/94.1, 713/153, 713/201, 709/218, 709/238, 709/229, 709/227, 711/147
• US Class Current: 370/389
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling

Abstract

A layer two forwarding protocol (L2F) provides virtual direct dial-up service into private networks through public internet service providers. An authorized remote client appears as a direct dial-up client to the home gateway, even through the client is accessing the home gateway remotely through the ISP. The new forwarding protocol allows the remote client to conduct point-to-point link protocols, such as point-to-point protocol (PPP) and serial line interface protocol (SLIP) directly with the local network home gateway. The network access server changes from a routing mode where a communication protocol is conducted with the client to a switching mode where the POP simply sends data from one port to a tunnel. The tunnel then transmits the data to another port, regardless of the header information on transmitted data packets. The remote client can then be managed through databases controlled by the local network and gain access to resources not typically accessible through the internet. The layer two forwarding protocol conducts an independent authorization session to prevent unauthorized access to the private network and provides point-to-point protocol transport over the internet independently of internet transport protocols.

Claims

1. An apparatus comprising:

a network processing device, residing outside of a local network, configured to identify virtual private connection headers encapsulating a point-to-point session; and

a network interface device configured to pass packets for the point-to-point session, established between the local network and a remote client, through an external Internet Protocol (IP) network in a virtual private connection based, at least in part, on the identification of the virtual private connection headers.

2. The apparatus according to claim 1 wherein the virtual private connection is established at a data link layer of the Open Systems Interconnect (OSI) model.

3. The apparatus according to claim 1 wherein the network processing device is configured to drop packets for the point-to-point session through the external Internet Protocol (IP) network that do not have headers associated with the virtual private connection.

4. The apparatus according to claim 1 wherein the network processing device establishes part of a layer-two tunnel that transports the point-to-point session over an IP network external to the local network.

5. The apparatus according to claim 1 wherein the network processing device receives and passes a dial-up point-to-point connection between the remote client and the local network over the virtual private connection.

6. The apparatus according to claim 1 wherein the remote client is a personal computer.

7. The apparatus according to claim 1 wherein the network processing device is a router located in an Internet Protocol (IP) network external from the local network that routes packets between the remote client and the local network over the virtual private connection.

8. A network processing device comprising:

a first interface configured to communicate with a remote client;

a second interface configured to communicate with a local network; and

a processor coupled between the first and second interface and operating in an Internet infrastructure external from the local network, the processor configured to pass packets through a virtual private point-to-point connection established in a portion of the Internet infrastructure between the remote client and the local network, wherein the packets for the virtual private point-to-point connection are encapsulated in a data link layer tunneling header and the processor is configured to pass the packets through the virtual private point-to-point connection according to information in the data link layer tunneling header.

9. The network processing device according to claim 8 wherein the processor passes through the packets encapsulated in data link layer tunneling headers associated with the virtual private point-to-point connection and drops packets that are not encapsulated in data link layer tunneling headers associated with the virtual private point-to-point connection.

10. The network processing device according to claim 8 wherein the processor is configured to pass tunnel negotiation packets through the Internet infrastructure between the remote client and the local network for negotiating a data-link layer tunnel over an external Internet Protocol (IP) network external to the local network, the network processing device then configured to pass the packets for the virtual private point-to-point connection over the negotiated tunnel.

11. The network processing device according to claim 8 wherein the network processing device is an Internet Protocol (IP) routing device.

12. An apparatus comprising:

a routing device configured to provide part of a virtual private connection for transporting a point-to-point session over an Internet Protocol (IP) network; and

a network interface device configured to pass packets for the point-to-point session through the virtual private connection according to data link layer headers encapsulating the point-to-point session, wherein the routing device is configured to identify the virtual private connection, and to drop packets that do not have data link layer headers encapsulating the point-to-point session.

13. The apparatus according to claim 12 wherein the routing device provides part of a tunnel established over the IP network for transporting the packets for the point-to-point session.

14. The apparatus according to claim 13 wherein the routing device forwards packets for the point-to-point session through the tunnel according to a data link layer protocol.

15. A method comprising:

establishing a portion of a tunnel over an Internet Protocol (IP) network between a remote client and a local network;

receiving packets that use a data link layer protocol to transport a virtual private point-to-point connection over the IP network, wherein the packets are encapsulated in data link layer headers; and

passing the packets associated with the virtual private point-to-point connection through the established portion of the tunnel according to the data link layer protocol when the data link layer headers are associated with the virtual private point-to-point connection.

16. The method according to claim 15 including receiving the packets for the virtual private point-to-point connection encapsulated in data link layer headers and passing the encapsulated packets through the IP network according to the data link headers.

17. The method according to claim 15 including passing the packets associated with the virtual private point-to-point connection through a portion of the IP network remote and external from the local network.