Using monitoring to control a proactive routing protocol

OLSR is a proactive routing protocol for mobile ad hoc networks. In OLSR, each node periodically collects two-hop neighbourhood information and sends topology control (TC) messages to update the link state. In this paper, rather than sending TC messages periodically, each node: (1) monitors the betweenness of its two-hop neighbourhood graph; (2) if the measure is in-control then no message is sent, otherwise a TC message is sent. This is effective because betweenness corresponds closely to the multi-point relay sets of OLSR. A significant change in the betweenness measure indicates a significant change in the network topology. Using this approach, the control overhead in OLSR is reduced by 26–46% with a corresponding savings in energy and little impact on throughput or delay.