[178622] in North American Network Operators' Group
Re: Verizon Policy Statement on Net Neutrality
daemon@ATHENA.MIT.EDU (Nick Hilliard)
Sun Mar 1 11:14:23 2015
X-Original-To: nanog@nanog.org
X-Envelope-To: nanog@nanog.org
Date: Sun, 01 Mar 2015 16:13:41 +0000
From: Nick Hilliard <nick@foobar.org>
To: Barry Shein <bzs@world.std.com>
In-Reply-To: <21746.35420.759630.472893@world.std.com>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On 01/03/2015 03:41, Barry Shein wrote:
> On February 28, 2015 at 23:20 nick@foobar.org (Nick Hilliard) wrote:
> > there were several reasons for asymmetric services, one of which was
> > commercial. Another was that most users' bandwidth profiles were massively
> > asymmetric to start with so it made sense for consumers to have more
> > bandwidth in one direction than another.
>
> How could they have known this before it was introduced?
because we had modem banks before we had adsl.
> I say that was prescriptive and a best guess that it'd be acceptable
> and a way to differentiate commercial from residential
> service. Previously all residential service (e.g., dial-up, ISDN) was
> symmetrical. Maybe they had some data on that usage but it'd be muddy
> just due to the low bandwidth they provided.
maybe it was symmetric on your modems; it wasn't on the modems I managed.
> Another still was that cross-talk
> > causes enough interference to prevent reverse adsl (i.e. greater bandwidth
> > from customer to exchange) from working well.
>
> So SDSL didn't exist?
SDSL generally maxes out at 2mbit/s and can be run near adsl without
causing problems, but that's not what I was talking about.
If you were to run a 24:1 adsl service with the dslam at the customer side,
it will cause cross-talk problems at the exchange end and that would trash
bandwidth for other adsl users in the exchange->customer direction.
> Anyhow, *DSL is falling so far behind it's
> difficult to analyze what could have been.
not really no. Spectral analysis is clear on efficiency measurement - we
know the upper limits on spectral efficiency due to Shannon's law.
> > > As were bandwidth caps.
> >
> > Bandwidth caps were introduced in many cases to stop gratuitous abuse of
> > service by the 1% of users who persistently ran their links at a rate that
> > the pricing model they selected was not designed to handle. You've been
> > around the block a bit so I'm sure you remember the days when transit was
> > expensive and a major cost factor in running an isp.
>
> It was the combination of asymmetric, no or few IPs (and NAT), and
> bandwidth caps.
let's not rewrite history here: IPv4 address scarcity has been a thing
since the very early 1990s. Otherwise why would cidr have been created?
> Sure. once it became institutionalized and the market got used to it
> why not sell tiered bandwidth services at different price points, but
> that could have been true of symmetrical service also.
my point is simply that there is often more to asymmetric services than
extracting more money from the customer.
Nick
