Timing system for modular cable modem termination system
First Claim
1. A modular cable modem termination system (CMTS), comprising:
- at least one packet shelf operating a data over cable service interface specifications (DOCSIS) media access controller (MAC);
one or more physical interface (PHY) shelves exchanging DOCSIS data with the packet shelf over a packet switched network; and
a timing system that synchronizes DOCSIS timing between the packet shelf and the downstream PHY shelves.
1 Assignment
0 Petitions
Accused Products
Abstract
A modular Cable Modem Termination System (CMTS) includes a packet shelf operating a Data Over Cable Service Interface Specifications (DOCSIS) Media Access Control (MAC) framer. One or more downstream Physical Interface (PHY) shelves receive DOCSIS data from the packet shelf over a packet switched network and modulate the DOCSIS data for sending on a downstream path of a cable plant. One or more upstream PHY shelves send DOCSIS data received from an upstream path of the cable plant over the packet switched network to the packet shelf. By separating the PHY components from the MAC and from the system software, the PHY components for a Hybrid Fiber Coax (HFC) plant may be replaced with different PHY components for other access technologies such as wireless, Digital Subscriber Lines (DSL), Ethernet-to-the-Home, Fiber-to-the-Home, or fiber Passive Optical Networks (PONs).
207 Citations
23 Claims
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1. A modular cable modem termination system (CMTS), comprising:
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at least one packet shelf operating a data over cable service interface specifications (DOCSIS) media access controller (MAC);
one or more physical interface (PHY) shelves exchanging DOCSIS data with the packet shelf over a packet switched network; and
a timing system that synchronizes DOCSIS timing between the packet shelf and the downstream PHY shelves. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A timing system for a cable network, comprising:
a timing circuit operating in a local packet shelf or local physical interface (PHY) shelf in a modular cable modem termination system (CMTS), the timing circuit either sending or receiving a timestamp over a packet switched network for synchronizing the local packet shelf or local PHY shelf with other packet shelves or PHY shelves in the modular CMTS. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for synchronizing components in a cable system, comprising:
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distributing a timestamp between a packet shelf and a physical interface (PHY) shelf in a modular cable modem termination system over a packet switched network; and
using the distributed timestamp to schedule data over cable service interface specifications (DOCSIS) transmissions in the cable system. - View Dependent Claims (16, 17, 18)
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19. A system for synchronizing components in a cable system, comprising:
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means for distributing a timestamp between a packet shelf and a physical interface (PHY) shelf in a modular cable modem termination system over a packet switched network; and
means for using the distributed timestamp to schedule data over cable service interface specifications (DOCSIS) transmissions in the cable system. - View Dependent Claims (20, 21, 22)
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23. A computer media containing instructions for synchronizing components in a cable system, the instructions when executed:
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distributing a timestamp between a packet shelf and a physical interface (PHY) shelf in a modular cable modem termination system over a packet switched network; and
using the distributed timestamp to schedule data over cable service interface specifications (DOCSIS) transmissions in the cable system.
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Specification