Simluating a satellite connection using dummynet?
kdk at daleco.biz
Sun Apr 23 21:54:22 UTC 2006
Dan Busarow wrote:
> On Apr 22, 2006, at 9:40 PM, Philip Hallstrom wrote:
>> Hi all -
>> Odd question for you. I have the opportunity to work
>> from home, but it would require using a sat internet
>> connection (no cable or dsl anywhere close).
>> I've been reading up on it and best I can tell I'm looking
>> at 1000ms round trips... at *best*. Most of what I do
>> I can do on servers at home, but there will be the
>> occasional ssh, etc.
>> I recently setup ipfw/dummynet with a pipe and a 750ms
>> delay both in and out and it wasn't as bad as I thought
>> it would be -- at least for ssh/text. Reminds me of my
>> days on a 9600 baud modem. heh.
>> I'm curious though whether this is a realistic test.
>> Any of you use satellite? How do you find it?
> I had StarBand for about two years. 1000ms RTT are the
> best you will see. pushing 2000ms is more like it.
> While it is possible to work via an SSH session it will
> try your patience.
> It is doable, and it allowed me to move out to the
> country, but that's about it. I now have a terrestrial
> radio link into the nearest town, 15 miles away, and
> it's beautiful.
My wife's employer had a Hughes connection for something
over a year. Generally speaking, they weren't impressed.
Their operation is a small insurance office, and they needed
quick https service to the home office in Iowa, for a web app
that seems to take a pretty quick pipe to operate well.
I never ran a sniffer, but it seemed as if their OS (Microsoft)
had some trouble with this setup, particularly with https
traffic. You'd wait a good long time (few seconds), then get a
big burst of data ... if you weren't cluttering things up with
retries. Since this HTTPS traffic was his "business", he
decided it was more important to keep his employees
happy, so he later decided to devote a portion of his
disposable income to a local outfit that provides a
T1 instead. TCP/IP being as it is, it's likely that MSFT
QoS was dropping the packet sizes to help deal
with the "congestion" ;-), but I was never sure.
I'd concur that 1000 ms was a pretty normal RTT for
ICMP, and it could, and often did go higher, a la
Much like Dan, I use an 11Mbps LOS radio connection
to the water tower about 4 miles away. Nice, except
I really need to raise my receiver so I can maintain
good QoS when the foilage gets going....
I think grog@ has satellite service in AUS. You might
see if you can turn up anything on his site.
And do you think (fop that I am) that I could be the Scarlet Pumpernickel?
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