Henrik Lundgren

A large-scale testbed for reproducible ad hoc protocol evaluations

We have built an ad hoc protocol evaluation testbed (APE) in order to perform large-scale, reproducible experiments. APE aims at assessing several different routing protocols in a real-world environment instead of by simulation. We present the APE testbed architecture and report on initial experiments with up to 37 physical nodes that show the reproducibility and scalability of our approach. Several scenario scripts have been written that include strict choreographic instructions to the testers who walk around with ORiNOCO equipped laptops. We introduce a mobility metric called virtual mobility that we use to compare different test runs. This metric is based on the measured signal quality instead of the geometric distance between nodes, hence it reflects how a routing protocol actually perceives the networks dynamics.

A testbed and methodology for experimental evaluation of wireless mobile ad hoc networks

Wireless mobile ad hoc network experimentation is subjected to stochastic factors from the radio environment and node mobility. To achieve test repeatability and result re-producibility such stochastic factors need to be controlled or assessed in order to obtain conclusive results. This has implications on the design of testbeds. We present a methodology that addresses repeatability and describe how it has guided us in the design of our Ad hoc Protocol Evaluation (APE) testbed. Finally, by using APE, we present side-by-side routing protocol comparison results and show a radio phenomena that is not visible in simulations.

Active routing for ad hoc networks

Ad hoc networks are wireless multihop networks whose highly volatile topology makes the design and operation of a standard routing protocol hard. With an active networking approach, one can define and deploy routing logic at runtime in order to adapt to special circumstances and requirements. We have implemented several active ad hoc routing protocols that configure the forwarding behavior of mobile nodes, allowing data packets to be efficiently routed between any two nodes of the wireless network. Isolating a simple forwarding layer in terms of both implementation and performance enables us to stream delay-sensitive audio data over the ad hoc network. In the control plane, active packets permanently monitor the connectivity and setup, and modify the routing state.

Embedding MANETs in the Real World

We believe that research on ad hoc networking so far has focused on too broad a range of scenarios and optimization issues and we argue that limiting the settings to bare bones services and small networks will allow for quick MANET deployment. Especially if these solutions interoperate easily with the Internet and offer the possibility to grow the MANET networks from there. Starting at this end will also help us to identify and possibly enlarge the “ad hoc horizon”, beyond which ad hoc networking is no longer useful. In this paper we report on our experiences from five years of real world ad hoc network experimentation. Our approach is pragmatic and includes several implementations and a testbed software package. We highlight issues that we have encountered and identify crucial problems and potential dangers that deserves special attention in order to make ad hoc networking usable.