in our neighborhood we've been having a lot of widespread comcast problems, which kind of made me stop looking at possible CPE causes for my sometimes spotty internet.
today speeds were slow again, and so just now i looked at the status page for my SB6141 and noticed that only 7 downstream channels were bonded and the worst of them had 27dB of SNR. (24, 26-31) i went around and tightened up as many F-connectors along the path inside the house, and a few minutes later 8 channels were up, the SNR on 24 had improved to 32dB from 27dB, and channel 25 was now up, albeit with 29dB of SNR. there had been uncorrectable errors ticking on channels 24-26 but those stopped incrementing after tightening up the connectors.
at that point, for fun i decided to power cycle the modem and was surprised to find that the downstream channels were now assigned to 1-8 and the SNR was 36dB across the board.
given that at lower frequencies the transmission line losses should be a little less, i wonder why the modem was trying to use channels 24-31 initially, and why after a reboot it selected somewhat "easier" channels after improving the connections.
anyone know how this works? is it just random? does the head-end assign the channels to use based on system utilization?
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