Patent ID: 7065779
Filing Date: 2006-06-20
Classification: H04L,H04N

Abstract:
1. A method for synchronizing time reference devices in an access network, the access network comprising a Head End and a plurality of nodes, the Head End including an access control system having a plurality of media access controllers, each media access controller controlling a respective interface to the access network, the plurality of media access controllers including a first distinct access controller for controlling a first interface, said first access controller including a first time reference device, said first interface including a first distinct plurality of ports for communicating with at least a first portion of the plurality of nodes, the plurality of access controllers further including a second distinct access controller for controlling a second interface, said second access controller including a second time reference device, said second interface including a second distinct plurality of ports for communicating with at least a second portion of the plurality of nodes, wherein the first access controller and the first interface reside on a first physical line card within the access control system, wherein the second access controller and the second interface reside on a second physical line card within the access control system, wherein the first plurality of ports includes a first downstream channel transmitter and at least one first upstream channel receiver, and wherein the second plurality of ports includes a second downstream channel transmitter and at least one second upstream channel receiver, the method comprising: providing at least one synchronization signal to said first and second access controllers; utilizing, at said first and second access controllers, said at least one synchronization signal in a manner which results in the first and second time reference devices being in synchronization with each other; providing a first time reference message to a first node on said first downstream channel, said first time reference being generated by said first time reference device; and receiving data from said first node at said Head End via said second upstream channel.