Re: VDSL

[Brandon Martin <lists.nanog () monmotha net>]

On 10/16/19 2:42 PM, Jeff Shultz wrote:
> But I'm confused a bit by the below - G.Fast is a twisted pair
> standard, last I saw - why would a cable (presumably coax) company be
> offering it?  Are they just taking over the PTT's inside wiring?

G.fast has definitions for both twisted pair and coax PHYs.  That gets 
everybody interested.

The biggest issue for the CATV operators is that the coax PHY 
monopolizes the cable meaning you can't use it for conventional 
channelized RF type services, so if the subscriber wants cable TV in 
addition to IP service, you either have to have a side-by-side IPTV 
deployment or revert to running DOCSIS over channelized RF next to your 
linear TV system.  I've seen micro fiber-fed DOCSIS nodes for this 
purpose.  DOCSIS 3.1 with a good RF budget and lots of channel space can 
get a few gigs of bandwidth which is quite usable for a midsize MDU. 
Chuck one of those down in the telco room, and you're good to feed 
potentially a couple hundred units using traditional DOCSIS+linear TV 
which is what people expect from a CATV operator.  Anyone who just wants 
IP service and ends up wanting tons of bandwidth can get moved over to 
packet-fed G.fast as needed.
--
Brandon Martin