A conservative scheme for distributed low-delay routing in MANETs

Delay-based routing is proved to improve the network´s round-trip time without enhancing its throughput. The reason is that optimising the end-to-end delay -as any load-based metric- creates route instability which results in packet reordering. This problem is detrimental for TCP. In the present work, we couple delay-based routing with a mechanism that locks, upon each node, the next-hop for each TCP flow, unless that hop becomes unavailable. The routes for future flows are proactively discovered by optimized link-state routing (OLSR) and reside in the node´s routing table, so the proposed mechanism is fully distributed. Simulation experiments in static and mobile scenarios for small pedestrian networks show that the use of path-locking in conjunction with delay-based routing alleviates the route oscillations and improves the TCP´s throughput.