DOCSIS 3.1 upstream

Jean-Francois Mezei jfmezei_nanog at
Fri Apr 15 02:43:04 UTC 2016

Canadian cable carriers seem to have all told the CRTC they can only
carry 42mhz in the upstream because their amplifiers and nodes only
amplify that narrow band in the upstream direction.

Is/was 42mhz common across north america ?

In a typical installation, how much of the 42mhz is actually usable for
upstream data ? (aka: how many 6mhz chunks are taken for TV STBs,
Telephony and whatever other upstream channels. I think I heard that one
6mhz chunk is used for one the low numbered TV analogue channels.
(although cablecos are slowly widthdrawing analogue TV now).

Am trying to figure out realistic bandwidth that a cableco with 42mhz
limits for upstream will get on 3.1.

Also, have cablecos with such limits for upstream begun to upgrade the
cable plant to increase the upstream bandwidth ? Canadian cablecos have
told the regulator it would be prohibitively expensive to do so, but
incumbents tend to exagerate these things when it is convenient. (they
can then claim higher costs/congestion/need for node splits which
increates regulated wholesale rates).

And would it be correct that in RFoG deployment, the 42mhz limit
disapears as the customer equipment talks directly tothe CMTS over fibre
all the way ?

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