SoylentNews

canopic jug [soylentnews.org] writes:

The IETF has published a discussion about how to deal with networking in high-latency situations [apnic.net] with occasional interruptions, such as interplanetary space where packet round trip times can make the traditional 3-way and 4-way handshake protocols quite impractical.

It takes some 2.4 to 2.7 seconds to send a signal to the moon and back. If we are talking about sending a signal to Mars and back, then the comparable delays are between 10 to 45 minutes. There is also the factor of extended interruption where an orbiting spacecraft is behind the object it is orbiting. If we look at communications with other planets in the solar system, there is a periodic interval when the planet aligns with the sun. For example, for an interval of around two weeks, the Earth’s view of Mars is blocked by the Sun every two years.

Such protracted Round-Trip Time (RTT) intervals are well beyond what we experience in the everyday Internet, even in the most bizarre of fault scenarios! For an end-to-end reliable protocol, the sender must retain a copy of the sent data until it is acknowledged as received from the other end. We have become used to a network where the RTT intervals are of a few tens of milliseconds, so simple interactions, such as a three-way TCP handshake, or a DNS query and response can happen within the limits of human perception. When such interactions blow out to some 30 minutes or so, is an end-to-end interaction model the right architectural choice?

There are a lot of assumptions which need to be verified or debunked. It is clear that a wholly new digital environment will be needed for deep space.

Original Submission