On Wed, 16 May 2001, Eric Cordian wrote:
> >> Still, the Internet is for the most part a Star Network, with only the
> >> very largest providers multi-homed.
>
> > This is not true, unless your definition of 'the very largest' is very
> > loose indeed. There are many thousands of multi-homed ISPs. People
> > periodically attempt to draw graphs of the relationships between
> > ISPs. If you look at these you see nothing similar to a star network.
>
> This hasn't been my experience here in the US. I am familiar with about
> 10 ISPs, from small mom and pop operations, to mid-size regional
> providers.
I have at least some knowledge of hundreds, in many different countries,
including the US. I was a director of the UK ISP association until last
week, and was one of the founders of the European ISP assocation,
EuroISPA.
> The smallest ones have a single line. Even a pretty big ISP can run on a
> single OC3, with a backup DS3.
>
> There are a few with a handful of OC12 and OC3 circuits, but these were
> generally obtained for specific customers.
>
> I can't imagine an ISP with 50+ distinct peers, with separate circuits
> to each.
You will find that the largest networks have many hundreds of peers.
Most peering is done across Internet exchange points such as the
LINX in London (120+ members), MAE East in Virginia, and MAE West
in San Jose. There are at least a dozen large exchange points in
the USA. While I haven't done any actual counting, my impression
is that having 50 or so peers at an exchange is normal. Certainly
when we connected to MAE West five or six years ago, we picked up
20-30 peerings immediately and with no difficulty.
Many or most exchange points publish peering matrixes. See
www.linx.net for an example.
> Unless you're UUNET or Sprint-sized, you generally get most of your
> bandwidth through a single pipe.
A significant number of our customers are ISPs. Many of them
are multi-homed. Some of our larger non-ISP customers are as well.
The first step in multi-homing is getting an autonomous system
number. Something in the region of 20,000 ASNs have been allocated.
This is a rough (very rough) measure of the number of multi-homed
organizations on the planet.
> No ISP is going to lose its connectivity, by refusing to delete a single
> customer their upstream provider doesn't like.
>
> If backbone providers start screening content, it's going to cause
> problems.
As the industry has told the UK government and the European
Commission in negotiations over the last several years, it's
actually technically impossible. Governments in Europe are always
on the brink of mandating screening of one sort or another. ISP
association spend a great deal of time educating them on what is
possible.
--
Jim Dixon VBCnet GB Ltd http://www.vbc.net
tel +44 117 929 1316 fax +44 117 927 2015
