Folks,
Internet over DVB forward path with a stabilised antenna.
Inmarsat return path via Inmarsat Packet Data with a stabilised antenna.
Pay per Mbyte on this.
That's 6-8 Mbits shared forward ( across all trains ) and 64Kbits return per
train.
john
----- Original Message -----
From: "Charlie Younghusband" <[email protected]>
To: "Andreas Timm-Giel" <[email protected]>; <[email protected]>
Sent: Wednesday, October 04, 2000 3:26 PM
Subject: Re: AW: Moving Targets
> At $7 US/minute @ 64kbps, that's $420 /hr @ 64kbps or 6720 US $ / hr @
1Mbps.
> Plus hw & ISP costs for down under. Yikes. Your research project could
end
> pretty quickly with an Inmarsat type solution.
>
> Want a real research project? Find a way to send the signal through the
train
> tracks. ;) Only way to really fix the tunnel problem!
>
> Seriously though, I'd talk to some of the wireless providers in Australia.
> Australia is quite advanced at digital wireless services, they might be
all over
> an additional excuse to expand their east coast network where most Aussie
cities
> are anyway.
>
> Charlie
>
> Also note that a 1Mbps downstream and a 56 upstream probably isn't a good
> matchup (an offhand guess); even if you're doing 100% downloading of
files, your
> upstream bandwidth could quickly become the bottleneck just with ACKs
assuming
> normal windows TCP/IP. Something closer to a 10 to 1 ratio might be more
> appropriate. Check some of the litterature regarding assymetry and
TCP/IP.
>
>
>
> Andreas Timm-Giel wrote:
> Second problem for L- and
>
> > S-band systems will be the prices for capacity on satellites (just as a
> > reference: Inmarsat takes around US$ 7 / min for a 64 kbit/s link)
>
> > >
> > > Hi,
> > >
> > > I'm doing a research project about providing Internet access to moving
> > > targets on the eastern seabord of Australia. In this case, the moving
> > > targets are trains.
> > >
> > > We really need to provide around 1MB or so downstream, maybe 56k or so
> > > uplink. I've been doing a lot of searching but facts seem to be hard
> > > to come by.
> > >--
>
> Charlie Younghusband
> Network Systems Engineering
> Xiphos Technologies http://www.xiphos.ca/
> 514-848-9640 (f) 514-848-9644
>
>
>
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