[AusNOG] DSL G.Fast Details

[Skeeve Stevens]

Hey Tony,

Then what is BT deploying in the UK?


...Skeeve


--

Skeeve Stevens - The ISP Guy

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On Tue, Feb 3, 2015 at 10:19 AM, Tony <td_miles at yahoo.com> wrote:

>
>
> After 250m it would probably be similar to VDSL performance (or it will
> drop back to VDSL).
>
> These faster technologies are just using the higher frequency spectrum, eg:
>
> ADSL - 1.1MHz
> ADSL2 - 2.2MHz
> VDSL - 12MHz
> VDSL2 - 30MHz
> G.fast - 106MHz (212MHz future)
>
> The problem being the higher frequency that you use, the shorter loop
> length you can support at that frequency/speed (ie. attenuation).
>
> All of the technologies have a "negotiation" (when the modem/dslam sync)
> where they test each frequency and decide which ones are able to be used.
> You would be familiar with this in the DSL world as "sycn speed". This
> means that on longer length cables, the higher frequencies are marked as
> unusable, discarded & speed drops accordingly.
>
> So if you were to look at your typical graph of speed v' distance, adding
> G.fast just pushes the very LHS of the graph up a bit higher at the very
> short distances. It doesn't reduce the speed or the distance of the 'tail'
> on the RHS (nor does it increase it).
>
>
> To quote from the wikipedia page you linked:
>
> "Limited demonstration hardware was demonstrated in mid-2013.[8] The first
> chipsets were introduced in October 2014, with commercial hardware expected
> in 2015, and first deployments planned for 2016."
>
> So is anyone deploying it in AU -> unlikely for at least another 2-3 years
> at the minimum.
>
>
> Those who are spruiking FTTN (over FTTP) show that G.fast as the logical
> upgrade to FTTN to increase the speeds from the currently suggested 25+Mbps
> with VDSL2+ FTTN rollout/trial. Of course the only way to do this is to
> shorten the copper loop length, by moving the 'node' closer to the end user
> (as you say, "shoebox on the pole" style).
>
>
> There is a lot of discussion of this on whirlpool already, have a look for
> some of those threads might possibly learn some more, as well as the merits
> of the relevant technologies (although WP discussions on the topic tend to
> dissolve into idealistic arguments for 5 pages at a time fairly regularly).
>
>
>
> regards,
> Tony.
>
>
> ________________________________
> From: Skeeve Stevens <skeeve+ausnog at theispguy.com>
> To: AusNOG Mailing List <ausnog at ausnog.net>
> Sent: Tuesday, 3 February 2015, 8:27
> Subject: [AusNOG] DSL G.Fast Details
>
>
>
> Hi all,
>
> BT (UK) have started deploying DSL G.FAST with a stated speed of up to
> 500mb.
>
> They have extended their VDSL2 Vectoring trial to 100 DSLAMs (
> http://www.telecompaper.com/news/bt-openreach-extends-vdsl-2-vectoring-tests-to-100-dslams--1062638
> )
>
> I found this: http://en.wikipedia.org/wiki/G.fast and the performance of
> the technology is quite interesting... especially inside buildings.
>
> Is anyone deploying this in Australia... and indeed, is this what NBNCo is
> planning to extend FTTN with?  The Wiki refer to deployments using this as
> FTTdp (distribution point)
>
> Does anyone know what the average distance from a NBNCo Node to the
> premises will be?
>
> The Wiki doesn't give much detail what happens after 250m
>
> I like how they say that the node is the size of a large shoebox and is
> often mounted on a pole.  That would be less than the size of most Bigpond
> Cable things on poles already in place.
>
> Just interesting to know more.
>
>
>
> ...Skeeve
>
> --
> Skeeve Stevens - The ISP GuyEmail: skeeve at theispguy.com ; Twitter:
> @TheISPGuy
> Blog: TheISPGuy.com ; Facebook: TheISPGuy
>
> Linkedin: /in/skeeve ; Expert360: Profile
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