Packet fiber node

• US 7,639,620 B2
• Filed: 03/06/2007
• Issued: 12/29/2009
• Est. Priority Date: 06/27/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Chapman, John T.
• Primary Examiner(s): Tran; Phuc H
• Application Number:
  US11/682,832
• Publication Number:
  US 20070150927A1
• Time in Patent Office: 1,029 Days
• Field of Search: 370/401, 370/489, 370/485, 370/235, 370/229, 370351-354, 370/356, 3703955-39552, 370/400, 725/129
• US Class Current: 370/235
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/58 Association of routers
• CPC Class Codes: H04L 45/60 Router architectures
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 11/0071 Provisions for the electrical-optical layer interface
• CPC Class Codes: H04Q 2011/0064 Arbitration, scheduling or medium access control aspects

Abstract

A packet fiber node is described for use in an access network such as, for example, a cable network. The packet fiber node may differ from convention RF fiber nodes deployed in a cable network in that the packet fiber node is configured to communicate with the Head End of the network using baseband optical signals rather than frequency modulated optical signals. According to a specific embodiment of the present invention, one or more packet fiber nodes may be deployed in a cable network to service a plurality of different subscriber groups which are serviced by a single, conventional RF fiber node.

Claims

1. A system, comprising:

a centralized Cable Modem Termination System (CMTS) component operating between a first network and a second cable network and configured to provide a plurality of cable modems access to the first network, wherein the centralized CMTS component is configured to perform a first portion of Data Over Cable Service Interface Specification (DOCSIS) processing on received packet traffic;

a distributed node located remotely from the centralized CMTS component and configured to perform, on communications received from the centralized CMTS component, a remaining second portion of the DOCSIS processing not performed by the centralized CMTS component, wherein the distributed node comprises;

a first interface configured to communicate with the centralized CMTS component;

a second interface in communication with the first interface and configured to communicate with the plurality of cable modems that are located in the second cable network;

circuitry in communication with the first and second interfaces and configured to perform the remaining DOCSIS processing, wherein the circuitry is configured to perform at least one selected from the group including downstream modulation, ranging, registration, generation of channel MAP messages, and generation and termination of Media Access Control (MAC) messages; and

the circuitry configured to transfer packets through the first interface and over a portion of the second cable network to the centralized CMTS component;

wherein the portion of the second cable network is located between the centralized CMTS component and the distributed node such that the distributed node is remotely located with respect to the centralized CMTS component.

2. The system of claim 1 wherein the circuitry is configured to establish one or more Internet Protocol (IP) tunnels for transferring the communications.

3. The system of claim 1 wherein the communications are passed from the centralized CMTS to the distributed node in digital form and the circuitry is configured to perform Quadrature Amplitude Modulation (QAM) to format the communications for transmission over a plurality of QAM channels extending to the cable modems.

4. The system of claim 1 wherein the first portion of DOCSIS processing includes a MAC layer operation.

5. An apparatus, comprising:

a first interface configured to communicate with a centralized Cable Modem Termination System (CMTS) component of a cable network through an Internet Protocol (IP) network;

a second interface in communication with the first interface and configured to communicate with one or more cable modems located in the cable network;

circuitry in communication with the first and second interfaces and configured to perform, on Data Over Cable Service Interface Specification (DOCSIS)-processed traffic received from the centralized CMTS component, a selected portion of CMTS functionality that is not performed by the centralized CMTS component, wherein the apparatus operates separately from the centralized CMTS and communicates with the centralized CMTS across the IP network, and wherein the selected portion of the CMTS functionality is quadrature amplitude modulation;

the circuitry configured to transmit the quadrature amplitude modulated traffic over Radio Frequency (RF) channels extending to the cable modems using the second interface.

6. The apparatus of claim 5 wherein the traffic is received over an IP tunnel, and wherein the received traffic is formatted according to DOCSIS Media Access Control (MAC) operations performed thereon prior to being received on the first interface.

7. The apparatus of claim 5 wherein the circuitry is configured to establish IP tunnels with the centralized CMTS component, the IP tunnels for transmitting the traffic from the centralized CMTS component to the apparatus.

8. A system, comprising:

a head end component located between a cable network and an access network, the head end component configured to perform a first portion of processing on data received over the access network, wherein the first portion of the processing includes Media Access Control (MAC) operations associated with a Data Over Cable Service Interface Specification (DOCSIS) protocol;

a node located remotely with respect to the head end component and a plurality of cable modems of the cable network, the node configured to perform a second portion of the processing on the data from the head end component; and

the node configured to transmit the processed data over Radio Frequency (RF) channels extending from the node to the cable modems;

wherein the head end component and the node form a distributed Cable Modem Termination System (CMTS) that extends across the cable network.

9. The system of claim 8 wherein the node is configured to perform downstream modulation on the data from the head end component.

10. The system of claim 8 wherein the node is configured to range with the cable modems.

11. The system of claim 8 wherein the head end component is configured to perform packet classification operations relating to downstream channel classification.

12. The system of claim 8 wherein the head end component is configured to conduct MAC management operations relating to MAC management of downstream channels.

13. The system of claim 8 wherein the data is transmitted from the head end component to the node in a digital form and is not modulated for RE transmission.

14. The system of claim 8 wherein the node is configured to register the cable modems.

15. The system of claim 8 wherein the node is configured to generate channel MAP messages.

16. A system, comprising:

a distributed node configured to communicate with a centralized Cable Modem Termination System (CMTS) component that operates between a first network and a second cable network and provides a plurality of cable modems access to the first network from the second cable network;

wherein, when operating, the distributed node forms a distributed CMTS with the centralized CMTS component;

the distributed node configured to receive, from the centralized CMTS component, packet traffic that has been partially Data Over Cable Service Interface Specification (DOCSIS)-processed by the centralized CMTS component;

the distributed node configured to perform, on the received packet traffic, a remaining portion of the DOCSIS processing, wherein the remaining DOCSIS processing includes quardrature amplitude modulation; and

the distributed node configured to transmit the quadrature amplitude modulated data over Radio Frequency (RF) channels extending from the distributed node to the cable modems.

17. The apparatus of claim 16, wherein the centralized CMTS component is configured to perform Media Access Control (MAC) operations associated with the DOCSIS protocol on the packet traffic before transmitting the packet traffic to the distributed node over an Internet Protocol (IP) tunnel.

18. The apparatus of claim 16, wherein the packet traffic is received over an IP tunnel, and wherein the received packet traffic is formatted according to DOCSIS MAC operations performed thereon prior to being received by the distributed node.