A Cross-Environment Study of Routing Protocols for Wireless Multi-hop Networks

We study ad hoc routing protocol mechanisms that impact the performance during and after periods of connectivity change. Our evaluation procedure is facilitated by using a structured and tool-supported approach, combining real world experiments with simulation and emulation. This method enables us to find performance-critical time regions in our traces. Our analysis shows that performance is largely determined by how accurately a protocol senses connectivity in these regions. Inaccurate sensing can seriously affect the performance of the protocol, even after the critical regions. We identify three significant problems with sensing that we call \emphSelf-interference, \emphTCP backlashing and \emphLink cache poisoning. We discuss their effect on the design of sensing mechanisms in routing protocols and suggest how the protocols can be made more robust.