Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1998-08-21
2001-08-28
Olms, Douglas (Department: 2732)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S355000, C370S395430, C370S401000, C370S465000
Reexamination Certificate
active
06282193
ABSTRACT:
TECHNICAL FIELD
The present invention relates to networks and, more specifically, to remote access servers connecting to packet networks.
BACKGROUND ART
FIG. 1
shows a system diagram of typical remote access servers (RAS)
2
and the interconnections for connecting a subscriber to the Internet. Currently, dial-up Internet access is provided to a subscriber through a remote access server typically located within the local calling area of the subscriber and maintained by either an Internet Service Provider (ISP) or a local or inter-exchange carrier on behalf of an ISP. A subscriber using a personal computer
4
dials into the remote access server
2
via a modem (not shown) and initiates a setup with the remote access server
2
. The call travels from the subscriber's modem to the telephone company's end office (EO)
6
which routes the call to the remote access server
2
. The remote access server
2
identifies and verifies that the subscriber is permitted to make a connection and have access to the Internet during setup. The subscriber may then send and receive data with the Internet
8
. The remote access server
2
provides the connection between the circuit-based network of the telephone system
3
and the packet-based network of the Internet
8
. One drawback of this configuration is that it requires the deployment of remote access servers
2
in close proximity to the ISP subscribers, in order to avoid long distance or toll charges for the subscriber, thereby making upgrades and repairs difficult for an Internet service provider.
FIG. 2
illustrates the architecture of a prior art remote access server
2
. The remote access server
2
receives telephone calls from the telephone network
3
into a circuit network server
12
. The circuit network server passes the circuit-based signals of each telephone call to a dial access server
14
via a circuit switch fabric
13
. The dial access server
14
demodulates the voice-band data of the circuit-based signals and extracts the Internet Protocol (IP) packets for routing to the appropriate Internet destination. The packets are passed to a packet network server
16
via a packet switch fabric
15
. From the packet network server
16
they are distributed into the packet network
8
. It is well known that a packet switch fabric
15
can be implemented with a variety of technologies, such as an arbitrated packet bus or a centralized switching module. The dial access server
14
uses the packet switch fabric
15
to move the extracted IP packets to a packet network server
16
and the associated packet network interface appropriate for delivering the packet to its intended destination. The architecture of
FIG. 2
carries the cost and complexity burden of two separate and independent switch fabrics: one circuit and one packet. In addition, the time division multiplexed structure of circuit network interfaces make them more costly at higher rates than the corresponding packet network interfaces.
SUMMARY OF THE INVENTION
The invention provides, in a preferred embodiment, a remote access server and method for using the remote access server in a packet network. In one embodiment, the remote access server provides a packet switch fabric, a packet network server and a dial access server. The packet network server has a first port for sending and receiving packet-based signals with the packet switch fabric and a second port for sending and receiving packet-based signals with the packet network. The dial access server has a port for sending and receiving packet-based signals with the packet switch fabric and the dial access server has a first digital signal processor for performing signal processing on the packet-based signals. The packet switch fabric transfers packet-based signals among the packet network server, and the dial access server. In a further embodiment, the dial access server further includes a second digital signal processor for performing signal processing on the packet-based signals.
The first digital signal processor may be a channel signal processor and the second digital signal processor may be a packet protocol processor. The signal processors perform remote access signal processing. The packet protocol processor may perform dial-up Internet protocol support. The channel signal processor may perform modulation and demodulation of packet-based signals, transcoding of packet-based signals, and automatic modem adaptation.
In other embodiments the packet switch fabric may include a switching module, a packet bus or a cell bus.
The remote access server may further include a management server coupled to the packet switch fabric providing management of remote access server resources where the packet switch fabric also transfers packet-based signals to the management server.
In another embodiment the remote access server includes an interface module for receiving and sending packet-based signals having embedded information packets and sending and receiving the embedded information packets. The server also includes a modem module for receiving the packet-based signal, performing demodulation on the packet-based signal, and extracting the embedded information packets or receiving the information packets and creating a packet-based signal with embedded information packets. The server further includes a packet switch fabric enabling transfer of the packet-based signal and the embedded information packets among the interface module and the modem module.
REFERENCES:
patent: 5852609 (1998-12-01), Adams, III et al.
patent: 5910970 (1999-06-01), Lu
patent: 5914955 (1999-06-01), Rostoker et al.
Hluchyj Michael G.
Risica Anthony J.
Bromberg & Sunstein LLP
Hom Shick
Olms Douglas
Sonus Networks
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