Method and apparatus for the synchronization of multiple cable modem termination system devices
First Claim
1. A communication system, comprising:
- a master cable modem termination system device having a first counter; and
a first slave cable modem termination system device having a second counter;
wherein the first slave cable modem termination system device sets the second counter based on a signal provided by the master cable modem termination system device; and
wherein the second counter is used to generate timing information for transmission by the first slave cable modem termination system device.
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Abstract
A plurality of CMTS devices are linked together and synchronized to facilitate communication between the respective CMTS devices and respective downstream cable modems. According to one embodiment of the invention, one of the CMTS devices is designated as a master device, and the other CMTS devices are designated as slave devices. The respective CMTS devices are connected to each other by means of a synchronization bus. The master CMTS device then generates and broadcasts a future time stamp value, which is received by the respective slave CMTS devices. When the time stamp counter in the master CMTS device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave CMTS devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the CMTS devices are synchronized.
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Citations
22 Claims
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1. A communication system, comprising:
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a master cable modem termination system device having a first counter; and a first slave cable modem termination system device having a second counter; wherein the first slave cable modem termination system device sets the second counter based on a signal provided by the master cable modem termination system device; and wherein the second counter is used to generate timing information for transmission by the first slave cable modem termination system device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A communication system, comprising:
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a first cable modem termination system device to transmit MAP information to a plurality of cable modems, the MAP information including identifiers associated with respective upstream channels that are connected to the cable modems; and a second cable modem termination system device connected to an upstream channel, wherein the second cable modem termination system device filters the MAP information based on an identifier of the MAP information that is associated with the upstream channel that is connected to the second cable modem termination system device. - View Dependent Claims (9, 10, 11)
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12. A method, comprising:
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storing time stamp information at a first slave cable modem termination system device having a first counter; setting the first counter of the first slave cable modem termination system device based on a signal provided by a master cable modem termination system device having a second counter; and generating timing information for transmission by the first slave cable modem termination system device using the first counter. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method, comprising:
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transmitting MAP information including identifiers associated with respective upstream channels from a first cable modem termination system device to cable modems connected to the upstream channels; and filtering the MAP information at a second cable modem termination system device based on an identifier of the MAP information that corresponds with an upstream channel that is connected to the second cable modem termination system device. - View Dependent Claims (20, 21, 22)
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Specification