Bidirectional communication system with ring configuration

• US 6,822,972 B1
• Filed: 09/12/2000
• Issued: 11/23/2004
• Est. Priority Date: 09/12/2000
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Farhan, Forrest M.
• Primary Examiner(s): PHAN, MAN U
• Application Number:
  US09/659,276
• Time in Patent Office: 1,533 Days
• Field of Search: 370/216, 370/222, 370/223, 370/224, 370/228, 370/227, 370/395, 370/431, 370/487, 370/468, 359/115, 359/118, 359/125, 359/137, 359/154, 359/167, 359/337, 398/2, 398/3, 398/59, 398/79, 398/82, 714/4, 714/716
• US Class Current: 370/487
• CPC Class Codes: H04B 10/275 Ring-type networks
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 12/4604 LAN interconnection over a backbone network, e.g. Internet, Frame Relay
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

A broadband communication system includes headend equipment for transmitting downstream signals and for processing upstream signals and communication devices coupled to one another in a bi-directional ring, where one of the communication devices functions as a hub that is coupled to the headend equipment for providing the upstream signals to, and receiving the downstream signals from, the headend equipment. A clockwise communication path couples the communication devices to one another for the reception and transmission of clockwise-traveling signals that include the downstream signals and at least a portion of the upstream signals, and a counterclockwise communication path couples the communication devices to one another for the reception and transmission of counterclockwise-traveling signals that include the downstream signals and at least a portion of the upstream signals. The system also includes subscriber equipment coupled to the communication devices for receiving the downstream signals and for generating the upstream signals. When a malfunction is detected in one of the communication paths, the functioning path is then employed to transmit the downstream signals to the communication devices that are no longer able to receive the downstream signals via the malfunctioning path.

Claims

1. A communication system, comprising:

headend equipment for transmitting downstream signals and for processing upstream signals;

a hub coupled to the headend equipment for forwarding the downstream signals and for providing the upstream signals to the headend equipment, wherein the hub comprises;

a clockwise receiver for receiving clockwise-traveling signals, a counterclockwise receiver for receiving counterclockwise-traveling signals; and

a data selector coupled to the counterclockwise receiver and the clockwise receiver for selecting one of the counterclockwise-traveling signals and the clockwise-traveling signals for transmission to the headend equipment;

a plurality of nodes coupled in a bi-directional nodal ring with the hub;

a clockwise communication path for coupling the plurality of nodes and the hub for the reception and transmission of the clockwise-traveling signals that include the downstream signals and at least a portion of the upstream signals;

a counterclockwise communication path for coupling the plurality of nodes and the hub for the reception and transmission of the counterclockwise-traveling signals that include the downstream signals and at least a portion of the upstream signals; and

subscriber equipment coupled to the plurality of nodes for receiving the downstream signals and for generating the upstream signals,

wherein, when a malfunction is detected in one of the counterclockwise communication path and the clockwise communication path, the other of the counterclockwise communication path and the clockwise communication path is employed to transmit the downstream signals to ones of the nodes that are no longer able to receive the downstream signals via the malfunctioning path.

2. The communication system of claim 1, wherein, when a malfunction is detected in one of the counterclockwise communication path and the clockwise communication path, the other of the counterclockwise communication path and the clockwise communication path is employed to transmit the upstream signals to ones of the nodes that are no longer able to transmit the upstream signals via the malfunctioning path.

3. The communication system of claim 2, wherein the downstream signals and the upstream signals provided over the counterclockwise communication path are processed by the subscriber equipment and the hub, respectively, unless the counterclockwise communication path malfunctions.

4. The communication system of claim 2, wherein each node comprises:

a counterclockwise receiver for receiving the counterclockwise-traveling signals transmitted over the counterclockwise communication path;

a clockwise receiver for receiving the clockwise-traveling signals transmitted over the clockwise communication path;

a counterclockwise transmitter for transmitting the counterclockwise-traveling signals over the counterclockwise communication path;

a clockwise transmitter for transmitting the clockwise-traveling signals over the clockwise communication path; and

a status processor coupled to the counterclockwise and clockwise receivers and transmitters for determining whether one of the counterclockwise communication path and the clockwise communication path has malfunctioned, and, in response to detecting a malfunction, for generating a control signal indicative of the malfunction, wherein the control signal is transmitted by one of the counterclockwise transmitter and the clockwise transmitter over the functioning communication path.

5. The communication system of claim 4, wherein each node further comprises:

a summing amplifier for receiving the upstream signals from the subscriber equipment and generating a summed signal;

an analog-to-digital converter coupled to the summing amplifier for converting the summed signal into a digital signal; and

a first digital summer coupled to the analog-to-digital converter and the counterclockwise receiver for summing the digital signal with counterclockwise data to generate a summed counterclockwise signal that is transmitted by the counterclockwise transmitter.

6. The communication system of claim 5, wherein each node further comprises a second digital summer coupled to the analog-to-digital converter and the clockwise receiver for summing the digital signal with clockwise data to generate a summed clockwise signal that is transmitted by the clockwise transmitter.

7. A broadband communication system, comprising:

headend equipment for transmitting downstream signals and for processing upstream signals;

communication devices coupled to one another in a bidirectional ring, wherein one of the communication devices functions as a hub that is coupled to the headend equipment for providing the upstream signals to, and receiving the downstream signals from, the headend equipment, wherein the hub comprises;

a clockwise receiver for receiving clockwise-traveling signals;

a counterclockwise receiver for receiving counterclockwise-traveling signals; and

a data selector coupled to the clockwise receiver and the counterclockwise receiver for selecting one of the counterclockwise-traveling signals and the clockwise-traveling signals for transmission to the headend equipment;

a clockwise communication path for coupling the communication devices to one another for the reception and transmission of the clockwise-traveling signals that include the downstream signals and at least a portion of the upstream signals;

a counterclockwise communication path for coupling the communication devices to one another for the reception and transmission of the counterclockwise-traveling signals that include the downstream signals and at least a portion of the upstream signals; and

subscriber equipment coupled to the communication devices for receiving the downstream signals and for generating the upstream signals,

wherein, when a malfunction is detected in one of the counterclockwise communication path and the clockwise communication path, the other of the counterclockwise communication path and the clockwise communication path is employed to transmit the downstream signals to ones of the communication devices that are no longer able to receive the downstream signals via the malfunctioning path.

8. The broadband communication system of claim 7, wherein, when a malfunction is detected in one of the counterclokwise communication path and the clockwise communication path, the other of the counterclokwise communication path and the clockwise communication path is employed to transmit the upstream signals to the communication devices that are no longer able to transmit the upstream signals via the malfunctioning path.

9. The broadband communication system of claim 8, wherein the downstream signals and the upstream signals provided over the counterclockwise communication path are processed by the subscriber equipment and the hub, respectively, unless the counterclockwise communication path malfunctions.

10. The broadband communication system of claim 8, wherein the communication devices include nodes.

11. The broadband communication system of claim 10, wherein each node comprises:

a counterclockwise receiver for receiving the counterclockwise-traveling signals transmitted over the counterclockwise communication path;

a clockwise receiver for receiving the clockwise-traveling signals transmitted over the clockwise communication path;

a counterclockwise transmitter for transmitting the counterclockwise-traveling signals over the counterclockwise communication path;

a clockwise transmitter for transmitter the clockwise-traveling signals over the clockwise communication path; and

a status processor coupled to the counterclockwise and clockwise receivers and transmitters for determining whether one of the counterclockwise communication path and the clockwise communication path has malfunctioned, and, in response to detecting a malfunction, for generating a control signal indicative of the malfunction, wherein the control signal is transmitted by one of the counterclockwise transmitter and the clockwise transmitter over the functioning communication path.

12. The broadband communication system of claim 11, wherein each node further comprises:

a summing amplifier for receiving the upstream signals from the subscriber equipment and generating a summed signal;

an analog-to-digital converter coupled to the summing amplifier for converting the summed signal into a digital signal; and

a first digital summer coupled to the analog-to-digital converter and the counterclockwise receiver for summing the digital signal with counterclockwise data to generate a summed counterclockwise signal that is transmitted by the counterclockwise transmitter.

13. The broadband communication system of claim 12, wherein each node further comprises a second digital summer coupled to the analog-to-digital converter and the clockwise receiver for summing the digital signal with clockwise data to generate a summed clockwise signal that is transmitted by the clockwise transmitter.