Intermittent Networking
®Developing-region networks rarely connect end-to-end
®Power, weather, reliability issues
®Sometimes intentionally intermittent:
®Low-earth orbit satellites: connect only while they are overhead
®“Mules” – moving basestation collects data
Basestation could be on a bus/motorcyle (DakNet)
®Extended coverage:
®User may periodically enter the coverage area (e.g. market/school)
®Internet doesn’t really handle this well…
®“Delay-tolerant Networking” Research Group  (dtnrg.org)
®Papers in last two SIGCOMMs
®But clearly fine for e-mail and voice mail..