Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1997-04-08
2001-08-21
Olms, Douglas (Department: 2661)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S338000
Reexamination Certificate
active
06278705
ABSTRACT:
RELATED APPLICATIONS
This application hereby incorporates by reference the following related non-provisional applications by the same inventors as the instant application: “Architecture To Support a Single System Image Across Multiple Network Access Servers,” having Ser. No. 08/835,536, and filing date Apr. 8, 1997; “Supporting Multilink Connections Across Multiple Network Access Servers,” having Ser. No. 08/835,534, and filing date Apr. 8, 1997; “Supporting Load Sharing Across Multiple Network Access Servers,” having Ser. No. 08/835,758, and filing date Apr. 8, 1997; and “Supporting Authentication Across Multiple Network Access Servers,” having Ser. No. 08/833,663, and filing date Apr. 8, 1997.
BACKGROUND
1. Field of the Invention
The present invention relates to systems for connecting telephone lines to computer networks, and more particularly to an architecture for providing a single system image across multiple network access servers, which connect telephone subscriber lines to a computer network.
2. Related Art
With the advent of computer networking and personal computers, telephone lines are increasingly being used to connect computer systems to computer networks such as the Internet. This has led to the development of network access servers for connecting telephone lines to computer networks. These networks access servers come in a number of forms.
Some network access servers include separate line servers and packet processors. Line servers connect to telephone lines and handle data communications across the telephone lines, for example handling modem scripts. Packet processors connect to a packet-switched network, such as the Internet, and coordinate communications across the packet-switched network. A packet processor makes decisions about whether a call can be accepted from a telephone line and how to forward the constituent data packets to the packet-switched network. Line servers and packet processors communicate with each other through a communication channel. Sometimes they use a tunneling protocol, such as the point to point tunneling protocol (PPTP) to communicate through the communication channel.
Other network access servers include a line server and a packet processor integrated together into a single module or box. The line server connects to telephone lines, and the packet processor connects to a packet-switched network. The line server and packet processor connect to each other through internal connections within the integrated module.
As telephone lines are being increasingly used to connect computers to computer networks, there is an increasing need for network access servers with larger numbers of ports to service larger numbers of telephone lines.
What is needed is a network access server architecture which can flexibly accommodate larger numbers of telephone lines.
SUMMARY
The present invention provides a modular architecture for connecting a plurality of network access servers together in a way that preserves a single system image across the plurality of network access servers. This modular architecture supports a variety of different types of connections. It supports multilink connections, in which a single connection uses multiple telephone lines for increased bandwidth. It supports spoofing, wherein an idle connection temporarily relinquishes its telephone line. It supports load sharing, wherein connections are distributed between network access servers. Finally, the modular architecture provides resources for performing authentication of a system user, including authentication using a security server.
Thus, the present invention can be characterized as an apparatus for routing communications between a plurality of telephone lines and a remote host on a packet-switched network, comprising a plurality of modules which include: a plurality of telephone ports coupled to respective telephone lines; a network interface coupled to the packet-switched network; and resources coupled to the network interface and the plurality of telephone ports for facilitating communications between telephone lines coupled to other modules and the remote host through the network interface.
According to one aspect of the present invention, modules communicate with each other using a tunneling protocol. In one variation of this embodiment, the tunneling protocol includes the PPTP protocol. In another variation, the tunneling protocol includes enhancements to the PPTP protocol.
The present invention can also be characterized as an apparatus for routing communications between a plurality of telephone lines and a remote host coupled to a data network, wherein the apparatus includes a communication channel and a plurality of modules, wherein modules include: a communication channel interface coupled to the communication channel; a plurality of telephone ports coupled to respective telephone lines; a network interface coupled to the data network; and resources coupled to the network interface and the plurality of telephone ports for facilitating communications between telephone lines coupled to other modules and the remote host through the network interface.
According to one aspect of this embodiment, resources included in the modules communicate with other modules using a tunneling protocol. In one variation of this embodiment, the tunneling protocol includes the PPTP protocol. In another variation, the tunneling protocol includes enhancements to the PPTP protocol.
According to another aspect of this embodiment, the resources for facilitating communications in the modules include: a plurality of physical ports for facilitating communications with associated telephone lines, and a plurality of logical ports for facilitating communication with logical connections to the remote host over the data network. In some instances, communications between a telephone line and the remote host flow through a physical port in a first module and a logical port in a second module.
The present invention can additionally be characterized as an apparatus for routing communications between a plurality of telephone lines and a remote host on a data network, including: a plurality of telephone ports coupled to the plurality of telephone lines; a first network interface coupled to the data network; and resources coupled to the network interface and the plurality of telephone ports for receiving through the network interface communications from telephone lines coupled to the data network and forwarding the communications from the first network interface to the remote host through a second network interface coupled to the data network.
The present invention can also be characterized as an apparatus for routing communications between a plurality of telephone lines and a remote host on a data network, comprising: a plurality of telephone ports coupled to the plurality of telephone lines; a communication channel interface coupled to a communication channel; a network interface coupled to the data network; and resources coupled to the communication channel interface, the network interface and the plurality of telephone ports for receiving communications from telephone lines coupled to the communication channel through the communication channel interface, and forwarding the communications to the remote host through the network interface.
The present invention can also be characterized as an apparatus for routing communications between a plurality of telephone lines and a remote host coupled to a data network comprising: a communication channel coupled to the remote host; a plurality of line servers coupled to the communication channel and the plurality of telephone lines; and a plurality of modules coupled to the communication channel including resources for facilitating communications between line servers and the remote host, the resources communicating with other modules to facilitate communications between the plurality of telephone lines coupled to the plurality of line servers and the remote host coupled to the data network.
The present invention can also be characterized as an apparatus for routing c
Chau Wing Cheong
Leu Darren
Liu Tze-jian
Nilakantan Chandy
Pao Jeffrey Kaiping
3Com Corporation
McDonnell & Boehnen Hulbert & Berghoff
Olms Douglas
Sam Phirin
LandOfFree
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