Verizon Policy Statement on Net Neutrality

Nick Hilliard nick at foobar.org
Sun Mar 1 16:13:41 UTC 2015


On 01/03/2015 03:41, Barry Shein wrote:
> On February 28, 2015 at 23:20 nick at 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




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