Measuring one-way delay in wireless mesh networks: an experimental investigation

Wireless Mesh networks are multi-hop networks mostly based on IEEE 802.11 technology and are considered as a viable alternative for providing broadband wireless Internet access. As a consequence, they require support for Quality of Service or advanced mechanisms for selecting Internet gateways. One important required information is the one-way delay between different nodes. In this paper, we have developed, implemented, and evaluated an one-way delay estimation technique for wireless mesh networks which is based on estimating intra node queuing and inter node forwarding delay. An IP-header option field is used to accumulate the per hop delay estimate to provide an end-to-end estimate. We also outline problems with the implementation and compare results with real one-way delays obtained from a 14 node mesh testbed. We show how estimation accuracy depends on network load and provide insights into further improvements.