A network built for one setting may need different assumptions in another. A NASA test of a deep space network may offer one example.
The Architecture of Delay
NASA's release said the agency had successfully tested the first deep space communications network modeled on the Internet. The release said engineers began a month-long series of DTN demonstrations in October. Engineers from NASA's Jet Propulsion Laboratory in Pasadena, Calif., used software called Disruption-Tolerant Networking, or DTN, to transmit dozens of space images.
Shifting the Burden of Reliability
NASA described the difference directly: unlike TCP/IP on Earth, the DTN does not assume a continuous end-to-end connection.
The release said that in its design, if a destination path cannot be found, the data packets are not discarded. Instead, it said, each network node keeps the information as long as necessary until it can communicate safely with another node.
One way to read this may be as a change in where a system keeps its patience. Rather than expecting a clear path from start to finish, a design like this may let each step in the chain hold on to what it has and wait. For people building systems that work across unreliable links, a similar question may be worth asking: what should happen to information when the next step is not available yet?
Perhaps growing into a harsher setting depends less on stretching a familiar design than on rethinking what it assumes.
Sources
- NASA Tests First Deep Space Internet - NASA, 2008-11-18
