We present Greedy Perimeter Stateless Routing (GPSR), a novel
routing protocol for wireless datagram networks that uses the po-
sitions of routers and a packet's destination to make packet for-
warding decisions. GPSR makes greedy forwarding decisions us-
ing only information about a router's immediate neighbors i
network topology. When a packet reaches a region where greedy
forwarding is impossible, the algorithm recovers by routing around
the perimeter of the region. By keeping state only about the local
topology, GPSR scales better in per-router state than shortest-path
and ad-hoc routing protocols as the number of network destinations
increases. Under mobility's frequent topology changes, GPSR can
use local topology information to nd correct new routes quickly.
We describe the GPSR protocol, and use extensive simulation of
mobile wireless networks to compare its performance with that of
Dynamic Source Routing. Our simulations demonstrate GPSR's
scalability on densely deployed wireless networks.