Architecture to support a single system image across multiple network access servers

• US 6,026,085 A
• Filed: 04/08/1997
• Issued: 02/15/2000
• Est. Priority Date: 04/08/1997
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Chau, Wing Cheong, Tai, Wayming Daniel, Wang, Xiaohu, Liu, Tze-jian, Leu, Darren, Sun, Tsyr-Shya Joe, Pao, Jeffrey Kaiping, Nilakantan, Chandy
• Primary Examiner(s): VU, HUY DUY
• Application Number:
  US08/835,536
• Time in Patent Office: 1,043 Days
• Field of Search: 370/352, 370/420, 370/421, 370/463, 370/400, 370/401, 370/237, 370/235, 370/389, 370/356, 379/93.01, 379/93.02, 379/93.04, 379/93.05, 379/93.07, 379/93.09, 379/93.14, 395/200.31, 395/200.32, 395/200.47, 395/200.48, 395/200.49, 395/200.5, 395/200.51, 395/200.53, 395/200.54, 395/200.55, 395/200.56 , 395/200.57, 395/200.58, 395/200.59, 395/200.6, 395/200.61, 395/200.65, 395/200.68, 395/200.73, 340/825.29
• US Class Current: 370/352
• CPC Class Codes: H04L 12/56 Packet switching systems
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors

Abstract

The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server. Finally, the present invention supports authentication across multiple network access servers using a security server, by allowing the network access servers to share authentication information.

Claims

1. An apparatus for routing communications between a plurality of telephone lines and a remote host, comprising:

a communication channel coupled to the remote host;

a plurality of line servers, line servers in the plurality of line servers coupled to the communication channel, and to telephone lines in the plurality of telephone lines; and

a plurality of packet processors coupled to the communication channel and including a plurality of ports for facilitating communications between line servers in

the plurality of line servers and the remote host, the ports for each packet processor including,

a first physical port for communications with one of the line servers, and a second physical port for communications with another packet processor, and

a plurality of logical ports for facilitating communications with logical connections to the remote host,

wherein a communication between a telephone line in the plurality of telephone lines coupled to a first line server and the remote host flows through the first physical port of a first packet processor and through the second physical port and logical port of a second packet processor using a tunneling protocol.

2. The apparatus of claim 1, wherein the tunneling protocol includes the PPTP protocol.

3. The apparatus of claim 1, wherein the communication channel includes a separate communication channel for communications between the plurality of packet processors.

4. The apparatus of claim 1, wherein the communication channel includes a separate communication channel for communications between the packet processors and line servers.

5. The apparatus of claim 1, wherein the communication channel includes a plurality of separate communication channels for communications between the packet processors and line servers.

6. The apparatus of claim 1, wherein the communication channel includes a separate communication channel for communications between the packet processors and the remote host.

7. The apparatus of claim 1, wherein the communication channel is a packet-switched network.

8. The apparatus of claim 1, wherein the communication channel is the Internet.

10. The apparatus of claim 1, wherein the a communication from one of the line servers to the remote host passes through the physical port of a third packet processor.

9. An apparatus for routing communications between a plurality of telephone lines and a remote host, comprising:

a communication channel coupled to the remote host;

a plurality of line servers, line servers in the plurality of line servers coupled to the communication channel and telephone lines in the plurality of telephone lines; and

a plurality of packet processors, each packet processor coupled to the communication channel and including a plurality of ports for facilitating communications between line servers in the plurality of line servers and the remote host,

wherein the ports of each packet processor include a logical port for communicating with logical connections to the remote host, and a physical port for communicating with other packet processors, and

wherein a communication from one of the line servers to the remote host sequentially passes through the physical port of the first packet processor, the physical port of the second packet processor, and the logical port of the second packet processor.

11. An apparatus for routing communications between a plurality of telephone lines and a remote host, comprising:

a communication channel coupled to the remote host;

a plurality of line servers, line servers in the plurality of line servers coupled to the communication channel and telephone lines in the plurality of telephone lines;

a plurality of modules, modules in the plurality of modules coupled to the communication channel and including resources for facilitating communications between line servers in the plurality of line servers and the remote host,

wherein the resources include, resources for communicating with other modules in the plurality of modules to facilitate communications between telephone lines in the plurality of telephone lines coupled to line servers in the plurality of line servers and the remote host,

a plurality of physical ports for facilitating communications with associated telephone lines in the plurality of telephone lines, a plurality of logical ports for facilitating communications with logical connections to the remote host; and

wherein a communication between telephone lines in the plurality of telephone lines and the remote host flows from a first telephone line in the plurality of telephone lines through a first physical port in the plurality of physical ports within a first module in the plurality of modules, and from a second telephone line in the plurality of telephone lines through a second physical port in the plurality of physical ports within a second module in the plurality of modules, communications from the first telephone line and the second telephone line flowing through a logical port in the plurality of logical ports within the second module in the plurality of modules.