Method for synchronization through accelerated advance of counters
View Patent ↗A method for synchronizing counters in a terminal device, such as a cable modem in a DOCSIS-based system, with those of an administrative device, such as a headend. A cable modem advances its frame counter. With each increment of the frame counter, the cable modem's minislot counter advances by an amount equal to the number of minislots per frame. Likewise, with each increment of the frame counter, the cable modem's timestamp counter is incremented by the number of timestamps per frame. This continues until the counters at the cable modem are within one frame of the headend's counters. The minislot counter is then incremented. With each increment of the minislot counter, the timestamp counter is incremented by an amount equal to the number of timestamps per minislot. This continues until the cable modem's counters are within a minislot of the headend's counters. The timestamp counter is then incremented until the cable modem's counters match those of the headend.
1. A method of synchronizing values within a set of counters to target values for each of the counters, wherein the set of counters comprises a first a second, and a third counter that count first, second, and third units of bandwidth, respectively, such that the first unit contains an X number of second units, and the second unit contains a Y number of third units, wherein X and Y are integers, the method comprising:
A. synchronously incrementing all counters until the third counter is within X times Y of the target value for the third counter;
B. synchronously incrementing the second and third counters until the third counter is within Y of the target value for the third counter; and
C. incrementing the third counter until the third counter is equal to the target value for the third counter.
2. The method of claim 1 , wherein said step A comprises:
unless the third counter is within X times Y of the target value for the third counter,
i incrementing the first counter by one;
ii incrementing the second counter by X; and
iii incrementing the third counter by X times Y.
3. The method of claim 1 , wherein said step B comprises:
unless the third counter is within Y of the target value for the third counter,
i incrementing the second counter by one;
ii incrementing the third counter by Y; and
iii if a first boundary is reached by the second counter incrementing the first counter by one, wherein the first boundary is the point at which incrementing the second counter triggers the first counter to increment by one during general operation.
4. The method of claim 1 , wherein said step C comprises:
i incrementing the third counter by one;
ii if a second boundary is reached by the third counter incrementing the second counter by one, wherein the second boundary is the point at which incrementing the third counter triggers the second counter to increment by one during general operation; and
iii if a first boundary is reached by the second counter incrementing the first counter by one, wherein the first boundary is the point at which incrementing the second counter triggers the first counter to increment by one during general operation.
5. The method of claim 1 , wherein the first, second, and third counters are DOCSIS frame, minislot, and timestamp counters, respectively.
6. The method of claim 1 , wherein the counters are within a terminal device and the target values are generated by an administrative device.
7. The method of claim 6 , wherein the terminal device is a cable modem and the administrative device is a cable modem termination system.