Oskar Wibling

Automatized Verification of Ad Hoc Routing Protocols

Numerous specialized ad hoc routing protocols are currently proposed for use, or being implemented. Few of them have been subjected to formal verification. This paper evaluates two model checking tools, SPIN and UPPAAL, using the verification of the Lightweight Underlay Network Ad hoc Routing protocol (LUNAR) as a case study. Insights are reported in terms of identifying important modeling considerations and the types of ad hoc protocol properties that can realistically be verified.

Graph grammar modeling and verification of ad hoc routing protocols

We present a technique for modeling and automatic verification of network protocols, based on graph transformation. It is suitable for protocols with a potentially unbounded number of nodes, in which the structure and topology of the network is a central aspect, such as routing protocols for ad hoc networks. Safety properties are specified as a set of undesirable global configurations. We verify that there is no undesirable configuration which is reachable from an initial configuration, by means of symbolic backward reachability analysis. In general, the reachability problem is undecidable.We implement the technique in a graph grammar analysis tool, and automatically verify several interesting nontrivial examples. Notably, we prove loop freedom for the DYMO ad hoc routing protocol. DYMO is currently on the IETF standards track, to potentially become an Internet standard.

Ad hoc routing protocol verification through broadcast abstraction

We present an improved method for analyzing route establishment in ad hoc routing protocols. An efficient abstraction for Propagating Localized Broadcast with Dampening (PLBD) is developed. Applying this result we are able to verify networks and topology changes for ad hoc networks up to the limits currently envisaged for operational mobile ad hoc networks (MANETS). Results are reported for route discovery in the Lightweight Underlay Network Ad hoc Routing protocol (LUNAR) using UPPAAL and we provide an outline of how similar verifications can be conducted for DSR.

Evaluating wireless multi-hop networks using a combination of simulation, emulation, and real world experiments

Mobile ad hoc networks suffer from complex interactions between protocols on different levels. To identify and explain anomalies found in real world experiments we propose to combine real world testing with simulation and emulation. By inspecting the differences in the results obtained using the three evaluation methods we can efficiently identify when anomalies occur and get a hint about where to further investigate. Our approach has proved to be valuable in an extensive comparison of the routing protocols AODV, DSR, and OLSR. The study resulted in two gigabytes of log data that required an efficient and structured method to isolate important time regions for further manual analysis. We discuss our approach and present some key findings.