  Delay and Disruption Tolerant Networks (DTNs) may lack continuous network
connectivity. Routing in DTNs is thus a challenge since it must handle network
partitioning, long delays, and dynamic topology. Meanwhile, routing protocols
of the traditional Mobile Ad hoc NETworks (MANETs) cannot work well due to the
failure of its assumption that most network connections are available. In this
article, a geographic routing protocol is proposed for MANETs in delay tolerant
situations, by using no more than one-hop information. A utility function is
designed for implementing the under-controlled replication strategy. To reduce
the overheads caused by message flooding, we employ a criterion so as to
evaluate the degree of message redundancy. Consequently a message redundancy
coping mechanism is added to our routing protocol. Extensive simulations have
been conducted and the results show that when node moving speed is relatively
low, our routing protocol outperforms the other schemes such as Epidemic, Spray
and Wait, FirstContact in delivery ratio and average hop count, while
introducing an acceptable overhead ratio into the network.
