A technology blog for The Economist Group IT team

Wednesday, September 22, 2004

Friend of the Rich and Famous...

Do you remember the article about wireless networks that I put on this site a few months ago ?
Yesterday I read another article about Wireless networking on ferries in Sydney harbour, and I sent an email about it to Bob Cringely who wrote the original column, (and numerous books, TV programmes etc). To my amazement, he replied back about an hour later with his thoughts on what I sent him.

Here's the email I sent him -

From: David Peach
To: bob@cringely.com
Date: 9/21/04 5:07PM
Subject: Wireless networks on ferries

Hi Bob,
I'm a regular reader of your column, and while I was reading this article - http://news.zdnet.co.uk/communications/networks/0,39020345,39167304,00.htm
which describes how the New South Wales Transit Authority are considering setting up wireless hotspots on the ferries which cruise around Sydney harbour, I couldn't help thinking how this would be a perfect application for your network of Sveasoft/Linksys routers.
There must be quite a few ferries in the harbour, and all the time, at least some of them would be near the water's edge and closer to land-based transmitters which could provide the uplink bandwidth. The other boats would be further out, but again close enough to other ferries for the whole system to work, probably. Would probably be cheaper than whatever else they've got planned to provide the actual net bandwidth. The fact that there aren't any obstacles in between the ferries, apart from other boats would also help the transmission range.
What do you think ?

Anyway, thanks for some interesting columns,
David Peach
Network Security Administrator
The Economist Newspaper

And about an hour later he replied back with this -

From: "Robert X. Cringely"
To: "David Peach"
Date: 9/21/04 5:50PM
Subject: Re: Wireless networks on ferries

It would be a good start, sure. But the emerging problem with these
firmware upgrade networks is that the routers, themselves, just don't
have as much computational power as they should. The first networks
being built are either in sparely-populated rural areas or they are
in very small urban neighborhoods. The Sveasoft system requires that
approximately 15 percent of the nodes be edge nodes -- nodes that
have hard-wired Internet connections. Those connections are
generally assumed to be DSL or cable modems but the fact is that you
could hang your WRT54G off a DS3 line and STILL only reliably serve
10-15 clients. There's a limit to the power you can buy for $79 but
this seems to be lost on many readers.

Now to the ferries. Yes, they have line-of sight to the entire
harbor and would be ideal switching nodes, but NOT running Linksys
routers. What you'd probably need is a small PC with several
available PCI slots. Use three of those slots for 802.11G adapters
running on channels 1,6 and 11 (in the U.S. -- Australia, like
Europe, uses 13 WiFi channels so I'm assuming there are 3-4 that
don't overlap so use those). Then use 1-3 additional PCI slots for
802.11a cards for load-balancing and backbone service between the
ferries and a few high-bandwidth shore installations. Instead of a
$79 solution that would support 6-10 connections this would be an
$800 solution that would support 300-400 connections and maybe more.
THAT's the direction we need to move toward.
Do you think I should write about this?

All the best,


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