would we build a bank where only some of the customers can get
their money back?
Not taking into account the FDIC, we already have that, since banks are only
required to keep 10% of any given depositor's monies.
we're selling delivery of packets at some
bandwidth. we should deliver it. otherwise, it's called false
No, it's called oversubscription, and it is what produces busy signals/dropped
packets/ slow response. What ISP doesn't oversubscribe consumer capacity?
When the full cost of that packet at that speed is not passed along to the
customer, then the only way for the ISP to remain viable (currently) is to
oversubscribe. The same occurs at the telco for POTS. The whole QoS angle
is just a way to get people to pay for something they think is better, but is
really no different in practice. (Fergie's smoke and mirrors).
So in essence there is already a 2 tier Internet, as has been said:
consumer-grade (oversubscribed), and real (1:1 bandwidth subscription). Real
means that if you buy a T1 or an OC3 or whatever, you get what you paid for,
to your ISP's PoP. Consumers don't get this; they get a burst bandwidth at
the burst rate, but there is no committed rate for consumers. Otherwise I
could get an OC-3 full rate for $1,500 per month (in the boonies, no less).
Where problems arise is when those who think they are getting 1:1 real
Internet (really just a pipe to their ISP) are actually getting
oversubscribed bandwidth instead of 1:1.
While marketing seems to be just short of sacrilege to many here, the fact is
that NOC personnel salaries have to be paid from somewhere, and if your
business is selling bandwidth, then your revenue from customers minus cost of
said bandwidth minus operational expenses (salaries, capital, power, etc) had
better result in a quantity that is greater than zero, or you're going to be
unemployed rather soon.
If you are selling $50 6Mb/s DSL, and you're paying $10 per Mb/s, then you
have a problem, and oversubscription is your solution. Oversubscribing 4 to
1 makes your non-oversubscribed $240 per month for four subscribers for your
bandwidth cost only $60 per month, and you now have $140 per month to pay
your NOC personnel and turn a profit (or at least break even). The local ISP
here is only oversubscribed two to one; I don't see how they are making any
money at all, even with fairly high DSL cost, as I've seen the kind of prices
their upstream charges for 1:1 rates.
Of course, your upstream (if you have one) also has to make their ends meet,
too. At the top SFI level, you still have the cost of transit to worry
about, with $1,000 per year or more per mile for fiber maintenance; if you
have 25,000 miles of fiber you need to generate $25 million per year to keep
it maintained, even if you don't have an upstream. Of course, the $35,000
per mile for fiber installation has to be amortized, too, as does that $2
million backbone router on each end of every hop, etc.
Bandwidth has to have a cost; otherwise the bandwidth provider will not stay
On the operational end, the challenge becomes designing networks that in the
presence of ubiquitous oversubscription degrade gracefully and allow certain
features to have lesser degradation. Thus QoS.