Efficient monitoring in wireless mesh networks: Overheads and accuracy trade-offs

802.11-based multi-hop wireless mesh networks have become increasingly prevalent over the last few years. Recently, a lot of focus has been on deploying monitoring frameworks for enterprise and municipal multi-hop wireless networks. A lot of work has also been done on developing measurement-based schemes for resource management and fault management in these networks. The above goals require an efficient monitoring infrastructure to be deployed in the wireless network, which can provide the maximum amount of information regarding the network status, while utilizing the least possible amount of network resources. However, network monitoring introduces overheads, which can impact network performance, from the perspective of the end user. The impact of monitoring overheads on data traffic has been overlooked in most of the previous works. It remains unclear, as to how parameters such as number of monitoring agents, frequency of reporting monitoring data, and others, impact the performance of a wireless network. In this work, we first evaluate the impact of monitoring overheads on data traffic, and show that even small amounts of overheads can cause large degradation in network performance. We then explore several different techniques for reducing monitoring overheads, while maintaining the objective (resource management, fault management and others) that needs to be achieved. Via extensive simulations, we investigate whether a monitoring framework, which is constrained in terms of number of monitors or periodicity of monitoring, can achieve similar performance as a monitoring framework spanning the entire network. We show that different techniques lend themselves to different application scenarios, and evaluate the trade-offs involved in terms of monitoring overheads and quality of monitoring data.