  Delay-tolerant networking (DTN) is a term invented to describe and encompass
all types of long-delay, disconnected, disrupted or intermittently-connected
networks, where mobility and outages or scheduled contacts may be experienced.
'DTN' is also used to refer to the Bundle Protocol, which has been proposed as
the one unifying solution for disparate DTN networking scenarios, after
originally being designed solely for use in deep space for the 'Interplanetary
Internet.' We evaluated the Bundle Protocol by testing it in space and on the
ground. We have found architectural weaknesses in the Bundle Protocol that may
prevent engineering deployment of this protocol in realistic delay-tolerant
networking scenarios, and have proposed approaches to address these weaknesses.
