Load-Balanced Routing in Wireless Networks: State Information Accuracy Using OLSR

To support QoS routing, accurate state should be available and manageable. But due to bandwidth constraints, communication costs, high loss rate and the dynamic topology of wireless networks, obtaining and keeping up-to-date state information is a very complex task. A commonly used QoS metric is router queue length, used as a load metric in a number of load-balancing routing protocols. In this paper, we explore how to accurately propagate information about a router's queue length in a network that runs the Optimized Link State Routing (OLSR) protocol. We report the quantification of state information accuracy under different traffic rates. The results show that state information is inaccurate, especially under high traffic rates. Tuning the OLSR protocol parameters has no noticeable impact on inaccuracy levels. Based on our initial analysis, we propose two additional techniques to collect queue length information as an attempt to reduce inaccuracies. We compare the different techniques against the basic OLSR, no additional improvements were observed. The results raise questions as to how load-balanced routing should be done in the face of non-negligible inaccuracies in the load metric.