Thread: 120M Uddingston upstream 3 channels?
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Old 13-08-2015, 11:24   #93
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Re: Uddingston upstream 3 channels?
Cable uses TDMA for upstream:

https://en.wikipedia.org/wiki/Time_d...ultiple_access

tl;dr:

Upstream channels are shared using TDMA. In TDMA, multiple modems cannot transmit at the same time. Each second is divided into thousands of slots, and these slots are dynamically divided between modems. Each modem then transmits in it's assigned time slot(s) so they don't interfere with each other.

And quoted from BV:

Quote:
Speaking of time slots, in DOCSIS lingo, a time slot is actually referred to as a "mini-slot". A mini-slot is made of an integer number of "ticks", depending upon the configuration of the CMTS. One tick is equal to 6.25 ?sec (micro seconds). So when speaking of burst times for cable modems, think of really short durations!
It's actually much the same as 2G (GSM) mobile phones.
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