I first came across the idea of DTN in 1996 when I had dinner with Vint Cerf in Palo ALto - he had just won the SIGCOMM award, and it was the job of the SIG Chair to take out the award winner for a jolly fine meal. He immediately started sketching on the paper table cloth the work he was doing with NASA to support the long-planned for manned mission to Mars, with (hopefully ,by then) commodoty networking equipment.
The idea that the RTT could change by several minutes during the time it takes for a packet to get from A to B (earth to mars ship) and the ack to get back was intriguing. The idea that noise might interfer with packets for a few minutes or hours (solar flares) was alarming.
Just how to solve this was the start of the Interplanetary Internet, and the technology to do it was the start of Delay (and Disruption) Tolerant Networking.
The following slides are sourced from several places, starting with (and thanks to) Kevin Fall's. The DTN work has spread into a much wider range of application scenarios than originally planned for, and so I have here material from Opportunistic and mobile social networks. Of course the DTN community is also very active in sensor networking too, especialyl in challenging environments such as sub-oceanic (one wonders if the french and english nuclear submarines recently could have learned a useful lesson here). Materials in the other slides are from members of the Haggle and Social Net EU projects (and me).
Pictures of, in and around the Talk
a great interview of Van Jacobson by Craig Partridge covering some pretty similar territory.