[ Thanks to Scott
for this link. ]
“NASA and Vint Cerf, a vice president at Google Inc.,
in Mountain View, Calif., partnered 10 years ago to develop this
software protocol. The DTN sends information using a method that
differs from the normal Internet’s Transmission-Control
Protocol/Internet Protocol, or TCP/IP, communication suite, which
Cerf co-designed.“The Interplanetary Internet must be robust to withstand delays,
disruptions and disconnections in space. Glitches can happen when a
spacecraft moves behind a planet, or when solar storms and long
communication delays occur. The delay in sending or receiving data
from Mars takes between three-and-a-half to 20 minutes at the speed
of light.“Unlike TCP/IP on Earth, the DTN does not assume a continuous
end-to-end connection. In its design, if a destination path cannot
be found, the data packets are not discarded. Instead, each network
node keeps the information as long as necessary until it can
communicate safely with another node. This store-and-forward
method, similar to basketball players safely passing the ball to
the player nearest the basket means information does not get lost
when no immediate path to the destination exists. Eventually, the
information is delivered to the end user.”