  This paper revisits the issue of route discovery in dynamic source routing
(DSR) for mobile ad hoc networks (MANETs), and puts forward a proposal of a
lightweight non-optimal route suppression technique based on the observation of
a rarely noted but commonly occurring phenomenon in route discovery. The
technique exploits the observed phenomenon to extract query state information
that permits intermediate nodes to identify and suppress the initiation of
route replies with non-optimal routes, even if the route query is received for
the first time. A detailed evaluation of DSR with non-optimal route suppression
is found to yield significant improvements in both protocol efficiency and
performance.
