[OT-ish] How big is the UK 'net?

[Ken Brown]

Peter Fairbrother wrote:
 
[...]

> How much would it cost the single central server for the connectivity? The
> server itself would cost around #10 million, how much do you think people
> would pay for truly anonymous email?

Nothing, I'm afraid :-(

> How many people have broadband?

Very few except at places of work. And when people say "broadband" in
the UK they usually fall for the hype and mean ADSL (which I personally
don't expect to take off, BT will continue to sit on it timidly the way
they sat on ISDN, which they delayed for so long it was near obsolete
before most people could afford it). Still nothing like the kind of
network speeds most workplaces and colleges now have. 

Your email scheme presumably involved large outgoing volumes  ad well as
incoming? Not good for ADSL (Part of the point of ADSL - almost the
whole point, really - is to throttle user's ability to send. It is the
favourite protocol of the Murdochs and the cable TV companies and the
big record companies who want us to be able to download large files from
them, but not to be able to serve files to anyone else). 
 
> If 100-500 MB/day is too much, can anyone come up with an acceptable traffic
> figure, per person, for 1 million users, that would not disrupt the 'net? I
> can perhaps squeeze it down further, but at the expense of some of the
> anonymity (partial).

For ordinary modem users - the vast majority of private Internet users -
100 Mb/day is far, far too much to download. Most of these people are
using POP3 still! 10Mb/day is probably a practical limit. Most home
users download mail from their ISP's servers. What would the effect be
on a server with, say, 10,000 users, if even 50 of them (half of one per
cent) suddenly had 100Mb in their mailbox, and tried to download it all
at once? 

No need to answer that - it happened to a server I manage just last week
:-(  What happens is that home users trying to use POP3 simply can't
read their mail, people with LAN-speed connections and IMAP users can,
sort of, but contention for memory in the server starts making things
really dodgy.  I'm not saying that mail servers can't be set up to
handle that sort of volume, of course they can, many handle far more
every day but a significant and sudden /increase/ of that amount
approximates to a DoS attack. 

There might also be network bottleneck issues with this sort of
bandwidth, probably at the ISPs. People don't read their mail evenly
over the day.  What happens to a large ISP if a thousand privacy-minded
users all try to download half a gig of mail at 18:00 when the boss has
gone home? (That's actually an argument for internationalising all this
as much as possible. Use up all that empty bandwidth at 04:00!)