[FoRK] Vint Cerf mods Android for interplanetary interwebs

Eugen Leitl eugen at leitl.org
Fri Nov 6 08:16:45 PST 2009

(yes, but is it in 2.0 yet?)


Vint Cerf mods Android for interplanetary interwebs

'Hot dead birds' protocol comes to earth

By Cade Metz in San Francisco • Get more from this author

Posted in Applications, 5th November 2009 18:40 GMT

OpenMobileSummit Internet founding father cum Google evangelist Vint Cerf is
working to bring his interplanetary interwebs protocol to mobile networks
here on earth.

In 1998, working in tandem with NASA's Jet Propulsion Laboratory, the
(co-)father of the seminal TCP protocol launched an effort to create an
"interplanetary extension to the internet." Initially, the team tried to make
this work with the good ol' TCP/IP protocol, but Cerf and crew soon realized
that this was a non-starter.

"There was a little problem called the speed of light," Cerf told a room full
of wireless-obsessives this morning at the OpenMobileSummit in San Francisco.
"When Earth and Mars are closest, we're 35 million miles apart, and it's a
three and a half minute trip one way, seven minutes for a round trip. Then
when we're farthest apart, we're 235 million miles - 20 minutes one way, 40
minutes round trip."

"Just try using TCP/IP for a 40 minute round trip."

Then there's the problem of celestial motion. "The planets rotate, and we
haven't figured out how to stop that," Cerf said.

"It's a very disruptive system, and it's potentially a variably delayed
system, because these planets are moving further apart based on our orbits."

So, Cerf and team booted TCP/IP from the heavens and build an interplanetary
replacement they called the Delay-Tolerant Networking (DTN) protocol. Cerf
admits this isn't the most attractive moniker.

"Engineers are really good at labeling and branding things," said his
sarcasm. "If we had named Kentucky Fried Chicken, it would have been Hot Dead

Unlike TCP/IP, DTN does not assume a continuous connection. When there are
delays in interplanetary transmission, the new protocol forces each node to
hang onto its packets until they can be safely transmitted. It's now under
test with platforms speeding away from earth towards objeccts 80 or 90
light-seconds away.

NASA first announced its successful tests last fall. And now, Cerf says, the
team is looking to bring DTN to earth. "We discovered there were terrestrial
applications of this very resilient delay tolerant protocol," he said. The
team first tested DTN on the ground in northern Sweden, using it to send data
to and from laptops speeding away in all terrain vehicles, and other
on-the-ground tests are underway elsewhere in Europe.

The ultimate goal - at least for Cerf - is to bring the protocol to our
earth's everyday wireless networks. The protocol, he says, has already been
added to Google's Android open source mobile stack as an application platform
- ie it sits on top of the OS.

Cerf and crew are also working to test the protocol with Cisco
router–equipped satellites. "We're eventually going to get to the point where
we can try out some of these ideas in the mobile department," Cerf said.
"There's relevance in the interplanetary stuff to terrestrial applications."

What applications, you ask? Well, almost anything. "Mobile operations are
highly stressed," Cerf said. "Mobiles are used where people congregate... in
a sense, mobile is already a dense and hostile environment. We all know that
when you drive around, coverage isn't very good...

"It's so hostile, it's clear that mobile could take advantage of these
more-resilient protocols. TCP/IP is very brittle. When you lose connectivity,
you lose connectivity, and most applications don't work anymore."

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