  We consider the problem of routing packets across a multi-hop network
consisting of multiple sources of traffic and wireless links while ensuring
bounded expected delay. Each packet transmission can be overheard by a random
subset of receiver nodes among which the next relay is selected
opportunistically.
  The main challenge in the design of minimum-delay routing policies is
balancing the trade-off between routing the packets along the shortest paths to
the destination and distributing traffic according to the maximum backpressure.
Combining important aspects of shortest path and backpressure routing, this
paper provides a systematic development of a distributed opportunistic routing
policy with congestion diversity ({D-ORCD}).
  {D-ORCD} uses a measure of draining time to opportunistically identify and
route packets along the paths with an expected low overall congestion. {D-ORCD}
is proved to ensure a bounded expected delay for all networks and under any
admissible traffic. Furthermore, this paper proposes a practical implementation
which empirically optimizes critical algorithm parameters and their effects on
delay as well as protocol overhead. Realistic Qualnet simulations for
802.11-based networks demonstrate a significant improvement in the average
delay over comparative solutions in the literature. %Finally, various practical
modifications to {D-ORCD} are proposed and their performance are evaluated.

Networking and Internet Architecture