  In this paper we propose HYMAD, a Hybrid DTN-MANET routing protocol which
uses DTN between disjoint groups of nodes while using MANET routing within
these groups. HYMAD is fully decentralized and only makes use of topological
information exchanges between the nodes. We evaluate the scheme in simulation
by replaying real life traces which exhibit this highly dynamic connectivity.
The results show that HYMAD outperforms the multi-copy Spray-and-Wait DTN
routing protocol it extends, both in terms of delivery ratio and delay, for any
number of message copies. Our conclusion is that such a Hybrid DTN-MANET
approach offers a promising venue for the delivery of elastic data in mobile
ad-hoc networks as it retains the resilience of a pure DTN protocol while
significantly improving performance.
