Method and apparatus for initialization of a cable modem

• US 6,230,326 B1
• Filed: 07/30/1998
• Issued: 05/08/2001
• Est. Priority Date: 07/30/1998
• Status: Expired due to Term

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Ulm, John, Unger, J. David, O'Neil, Eugene E. Jr., Sawyer, Wilson
• Primary Examiner(s): Faile, Andrew
• Assistant Examiner(s): Tran, Hai V.
• Application Number:
  US09/126,557
• Time in Patent Office: 1,013 Days
• Field of Search: 348/10, 348/12, 348/13, 348/6, 455/226.3, 455/62, 455/324, 455/5.1, 725/111, 725/117, 725/118
• US Class Current: 725/111
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

A method and apparatus for initialization and operation of cable modems comprising initializing the cable modems over management channels and transferring the cable modems to a data channel for operation. Initialization over a management channel overcomes certain prior art constraints associated with initialization over the data channel.

Claims

1. A method of initializing cable modems comprising:

a cable modem termination system transmitting on a downstream channel messages providing upstream management channel information for an upstream management channel, the upstream management channel being designated as a channel to be used by a cable modem for transmitting an initialization request to the cable modem termination system; and

the cable modem termination system receiving the initialization request from the cable modem via the upstream management channel; and

upon completion of initialization of the cable modem, the cable modem termination system notifying the cable modem to switch to a data channel for upstream data transmission

wherein the cable modem termination system has N upstream data channels and N+1 upstream receivers and wherein the initialization request is received on the N+1 upstream receiver.

2. The method of claim 1 further comprising:

the cable modem termination system transmitting data channel initialization information to the cable modem for the data channel.

3. The method of claim 1 wherein the cable modem termination system broadcasts the upstream management channel information.

4. The method of claim 2 wherein the cable modem termination system multicasts the data channel initialization information.

5. The method of claim 2 wherein the cable modem termination system unicasts the data channel initialization information.

6. The method of claim 1 wherein the upstream management channel information is transmitted in upstream channel descriptors and allocation maps.

7. The method of claim 1 wherein the initialization request is a ranging request.

8. A cable modem termination system comprising:

a plurality of receiver circuits coupled to a plurality of inputs;

a first switch coupled to the plurality of inputs and an extra input, the first switch to switch through either one of the plurality of inputs or the extra input;

a second switch coupled to an output of the first switch and the extra input, the second switch to switch through either the output of the first switch or the extra input; and

an extra receiver circuit coupled to receive an output of the second switch.

9. The cable modem termination system of claim 8 wherein the extra receiver circuit is configured to function as a diagnostic receiver.

10. The cable modem termination system of claim 8 wherein the extra receiver circuit is configured to function as a backup receiver when one of the plurality of receiver circuits fails.

11. The cable modem termination system of claim 8 wherein the extra receiver circuit is configured to function as a spectrum analyzer.

12. The cable modem termination system of claim 8 wherein the extra receiver is utilized to allow a cable modem connected to the cable modem termination system to switch from a first frequency to a second frequency.