Internet on the ISS?

From the ISS I'm betting that their internet goes over the Tracking and Data
Relay Satellites....which are in geostationary orbit. So its extremely
similar to someone on the earth using it....the only problem is that there's
blackout periods due to the inclination fo their orbit.
Tom

"Derek Lyons" wrote in message
...
"m" wrote:

tcp ip over geostationary satellite works fine.I use it everyday.Here in
Europe are many (relatively cheap)providers.So the implementation to the
ISS
would be no problem if not done yet

I invite you consider the difference between a geostationary bird and
a LEO bird.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

In sci.space.history Henry Spencer wrote:
In article ,
Ami Silberman wrote:
The real problems with using internet protocols out of the box is that they
are not set up for SATCOM, much less deep space communications. TCP, for
example, starts out with small packets and short time outs to wait for
acknowledgements.

Actually, TCP itself was designed from the start to be usable over
satellite links -- the Arpanet (ultimate ancestor of today's Internet)
included satellite links pretty much from the start. But existing TCP
*implementations* are rarely configured for that.

Deep space is another story entirely. Time delays of many minutes call
for very different approaches.
... look at this: http://ipinspace.gsfc.nasa.gov/
Regards
Adam Przybyla

Deep space is another story entirely. Time delays of many minutes call
for very different approaches.

... look at this: http://ipinspace.gsfc.nasa.gov/

Well, what is most interesting about the "IP in space" concept (as far
as I can tell) isn't so much how the bits are arranged, but making it
easier for data and commands to go to/from researchers to the craft,
so that mission control doesn't need to touch everything manually.

As for actual protocols, it looks like TCP (which is the standard way
to run FTP, HTTP, SMTP, etc) is indeed unusable in deep space. At
least according to the enclosed quote. This page also touches on a
few of the more obscure issues (selective ACK in TCP, for example)
which have come up in earth orbit (not deep space) work.

http://ipinspace.gsfc.nasa.gov/faq.html

Doesn't IP fail in space due to long propagation delays?

This is a misconception that is brought about by confusing IP, a layer
3 network protocol, with TCP, a layer 4 transport protocol. IP is
strictly an end-to-end addressing mechanism. IP packet headers have a
source address, an destination address, and a few bytes of
options. These get slapped on a packet which is then sent on it's
merry way and forgotten about. Network layer protocols do not perform
handshaking or retransmission. These functions get performed at a
higher layer. As a result, IP is insensitive to transmission delay. It
will work equally well across the room or out to Pluto. It will even
work over uindirectional links. UDP, a layer 4 transport protocol,
will also work over unidirectional links, allowing applications to be
built that are not sensitive to delay. TCP, on the other hand,
requires a bidirectional link to perform handshaking. The
round-trip-time and the TCP "window" buffer size combine to restrict
the maximum throughput possible over a TCP connection. TCP experiments
have been done with the ACTS satellite in geosynchronous orbit that
achieved a throughput of 540 Mbits/sec. It appears that TCP is quite
useable in a planetary neighborhood, out to about lunar
distance. Beyond that, UDP-based applications are called for.

On 26 Sep 2005 11:29:06 -0400, in a place far, far away, Jim Kingdon
made the phosphor on my monitor glow in such a way
as to indicate that:

Deep space is another story entirely. Time delays of many minutes call
for very different approaches.

... look at this: http://ipinspace.gsfc.nasa.gov/

Well, what is most interesting about the "IP in space" concept (as far
as I can tell) isn't so much how the bits are arranged, but making it
easier for data and commands to go to/from researchers to the craft,
so that mission control doesn't need to touch everything manually.

As for actual protocols, it looks like TCP (which is the standard way
to run FTP, HTTP, SMTP, etc) is indeed unusable in deep space. At
least according to the enclosed quote. This page also touches on a
few of the more obscure issues (selective ACK in TCP, for example)
which have come up in earth orbit (not deep space) work.

Boeing had someone from Cisco working with them on the exploration
architecture studies, and he recommended UDP for the communications
architecture.