  Realizing delay-capacity in intermittently connected mobile networks remains
a largely open question, with state-of-the-art routing schemes typically
focusing either on delay or on capacity. We show the feasibility of routing
with both high goodput and desired delay constraints, with REAPER (for
Reliable, Efficient, and Predictive Routing), a fully distributed convergecast
routing framework that jointly optimizes both path length and path delay. A key
idea for efficient instantiation of REAPER is to exploit predictability of
mobility patterns, in terms of a semi-deterministic model which appropriately
captures several vehicular and human inter-contact patterns. Packets are thus
routed using paths that are jointly optimal at their time of arrival, in
contrast to extant DTN protocols which use time-average metrics for routing.
REAPER is also self-stabilizing to changes in the mobility pattern. A
simulation-based evaluation confirms that, across the spectrum of ultra-light
to heavy traffics, REAPER achieves up to 135% and 200% higher throughput and up
to 250% and 1666% higher energy efficiency than state-of-the-art single-copy
protocols MEED-DVR and PROPHET, which optimize a single metric only,
specifically, expected delay and path probability respectively.
