PACKET FIBER NODE

• US 20070150927A1
• Filed: 03/06/2007
• Published: 06/28/2007
• Est. Priority Date: 06/27/2001
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Chapman, John
• Granted Patent: US 7,639,620 B2
• Time in Patent Office: Days
• US Class Current: 725/111
• 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. An apparatus comprising:

a first interface to communicate with a remote Head End that is located between a first network and a second cable network and that provides one or more cable modems access to the first network;

a second interface to communicate with the one or more cable modems that are located in the second cable network;

a Data Over Cable Service Interface Specification (DOCSIS) PHY to output packets that correspond to Radio Frequency (RF) signals that are sent from the cable modems and received by the apparatus over the second interface, the outputted packets addressed to the Head End and representing information included in the received RF signals; and

the DOCSIS PHY to transfer the packets through the first interface and over a packet switched portion of the second cable network to the Head End;

wherein the packet switched portion of the cable network is located between the DOCSIS PHY and the Head End such that the DOCSIS PHY is remotely located with respect to the Head End.

2. The apparatus of claim 1 further comprising one or more processors operable when executing tunneling software instructions including in memory located within the apparatus to establish one or more Internet Protocol (IP) tunnels for transferring the packets.

3. The apparatus of claim 1 further comprising a network layer for formatting the packets for transmission over the packet switched network.

4. The apparatus of claim 1 wherein the DOCSIS PHY further includes a modulator for modulating signals sent from the Head End before downstream transmission to the cable modems.

5. An apparatus comprising:

a first interface for communicating with a remotely located Head End of a cable network;

a second interface for communicating with one or more cable modems located in the cable network;

a Data Over Cable Service Interface Specification (DOCSIS) PHY for converting packets that are sent from the Head End and received by the apparatus over the second interface into downstream frames;

the DOCSIS PHY to output Radio Frequency (RF) signaling representing the downstream frames for transfer over the cable network to the cable modems using the second interface.

6. The apparatus of claim 5 wherein a path for the packets sent from the Head End to the apparatus extends through a packet switched network.

7. The apparatus of claim 5 further comprising a network layer to obtain Internet Protocol (IP) addresses that correspond to the cable modems for the received packets before providing the packets to the DOCSIS PHY.

8. The apparatus of claim 5 wherein the DOCSIS PHY further includes a demodulator for demodulating signals sent from the cable modems before upstream transmission.

9. A system for use in an access network comprising:

a Head End located between a cable network and an access network;

one or more cable modems located in the cable network;

one or more intermediary nodes located remotely with respect to the Head End and the cable modems and operable to facilitate communications between the Head End and the cable modems;

the intermediary nodes operable to communicate with the Head End using first signals that are received at the intermediary nodes from the Head End and transmitted to the Head End by the intermediary nodes; and

the intermediary nodes operable to communicate with the cable modems using second modulated signals that are received at the intermediary nodes from the cable modems and transmitted to the cable modems by the intermediary nodes.

10. The system of claim 9 wherein at least one of the intermediary nodes includes a Data Over Cable Service Interface Specification (DOCSIS) PHY that includes a demodulator.

11. The system of claim 9 wherein the intermediary nodes are further operable to permit the Head End to perform service flow management operations relating to downstream channel service flow management.

12. The system of claim 9 wherein the intermediary nodes are further operable to permit the Head End to perform packet classification operations relating to downstream channel classification.

13. The system of claim 9 wherein the intermediary nodes are further operable to permit the Head End to conduct Media Access Control (MAC) management operations relating to MAC management of downstream channels.

14. The system of claim 9 wherein the first signals are not modulated and include packets.

15. The system of claim 14 wherein the packets are transferred between the intermediary nodes and the Head End over a packet switched portion of the cable network.

16. The system of claim 9 wherein the packets transmitted between the Head End and the intermediary nodes are transmitted using a tunneling protocol.

17. A method comprising:

demodulating signals received from one or more cable modems before transferring the demodulated signals upstream; and

modulating signals received from an upstream Cable Modem Termination System (CMTS) before transferring the modulated signals downstream to the cable modems.

18. The method of claim 17 wherein the demodulated signals are transferred upstream using a packet switched portion of a cable network.

19. The method of claim 17 further comprising establishing a tunnel extending to the upstream CMTS for transferring the demodulated signals upstream.

20. The method of claim 17 wherein the signals received from the cable modems include frames with a destination address identifying a Media Access Control (MAC) address of the upstream CMTS and the MAC address.

21. The method of claim 17 wherein the MAC address is not modified before transferring the demodulated signals upstream.