Statistical model checking of ad hoc routing protocols in lossy grid networks

We extend recent work by Hofner and McIver con the performances of the ad hoc routing protocols AODV and DYMO in terms of routes established. Hofner and McIver apply statistical model checking to show that on arbitrary small networks (up to 5 nodes) the most recent, and apparently more robust, DYMO protocol is less efficient than AODV. Here, we reformulate their experiments on 4x3 toroidal networks, with possibly lossy communication. As a main result we demonstrate that, in this more realistic scenario, DYMO performs significantly better than AODV

A process algebra for wireless mesh networks used for modelling, verifying and analysing AODV

We propose AWN (Algebra for Wireless Networks), a process algebra tailored to the modelling of Mobile Ad hoc Network (MANET) and Wireless Mesh Network (WMN) protocols. It combines novel treatments of local broadcast, conditional unicast and data structures. In this framework we present a rigorous analysis of the Ad hoc On-Demand Distance Vector (AODV) protocol, a popular routing protocol designed for MANETs and WMNs, and one of the four protocols currently standardised by the IETF MANET working group. We give a complete and unambiguous specification of this protocol, thereby formalising the RFC of AODV, the de facto standard specification, given in English prose. In doing so, we had to make non-evident assumptions to resolve ambiguities occurring in that specification. Our formalisation models the exact details of the core functionality of AODV, such as route maintenance and error handling, and only omits timing aspects. The process algebra allows us to formalise and (dis)prove crucial properties of mesh network routing protocols such as loop freedom and packet delivery. We are the first to provide a detailed proof of loop freedom of AODV. In contrast to evaluations using simulation or model checking, our proof is generic and holds for any possible network scenario in terms of network topology, node mobility, etc. Due to ambiguities and contradictions the RFC specification allows several interpretations; we show for more than 5000 of them whether they are loop free or not, thereby demonstrating how the reasoning and proofs can relatively easily be adapted to protocol variants. Using our formal and unambiguous specification, we find shortcomings of AODV that affect performance, e.g. the establishment of non-optimal routes, and some routes not being found at all. We formalise improvements in the same process algebra; carrying over the proofs is again easy

A Formal Framework for Mobile Ad hoc Networks in Real-Time Maude

Mobile ad hoc networks (MANETs) are increasingly popular and deployed in a wide range of environments. However, it is challenging to formally analyze a MANET, both because there are few reasonably accurate formal models of mobility, and because the large state space caused by the movements of the nodes renders straight-forward model checking hard. In particular, the combination of wireless communication and node movement is subtle and does not seem to have been adequately addressed in previous formal methods work. This paper presents a formal executable and parameterized modeling framework for MANETs in Real-Time Maude that integrates several mobility models and wireless communication. We illustrate the use of our modeling framework with the Ad hoc On-Demand Distance Vector (AODV) routing protocol, which allows us to analyze this protocol under different mobility models.Ope

High Performance Firewalls in MANETs

Doing route selection based in part on source addresses is a form of policy routing, which has started to receive increased amounts of attention. In this paper, we extend our previous work on ROLF (ROuting as the Firewall Layer) to achieve source prefix filtering. This permits easy definition of "inside" and "outside", even in MANET environment where there is no topological boundary. We present algorithms for route propagation and packet forwarding using ROFL, we measure its performance in a simulated environment with two different ad hoc routing protocols. Simulation results demonstrate that ROFL can significantly reduce unwanted packets without extra control traffic incurred, and thus improves overall system performance and preserves battery power of mobile nodes. ROFL is the first scheme to provide a concrete defense against some battery exhaustion attacks in MANETs. Moreover, it requires only minor changes to existing ad hoc network routing protocols, making it practical and feasible to be deployed in real world

Formal Modeling and Analysis of Mobile Ad hoc Networks

Fokkink, W.J. [Promotor]Luttik, S.P. [Copromotor

Modeling and verifying the OLSR protocol using Uppaal

Masteroppgave i Informasjons- og kommunikasjonsteknologi IKT590 Universitetet i Agder 2014Wireless Mesh Networks (WMNs) are a popular technology due to their exibility andself-organizing nature that provide support for broadband communication. They areused in a wide range of application areas, such as public transportation, tunnels, realtime racing car telemetry and emergency response communication. Route _nding andmaintenance, two important factors determining the performance of such networks,are provided using routing algorithms. The Optimized Link State Routing (OLSR)protocol is an example of such algorithms which is used in this study.One issue about this protocol is that its speci_cation is in English that may causeambiguities or di_erent interpretations. The _rst contribution of this project is thedevelopment of a formal and unambiguous model of OLSR and its main functionalitiesusing timed automata as our formal speci_cation language. The second contributionof the project is a precise analysis of OLSR using the model checker Uppaal. By acareful automated analysis with Uppaal, the project shows a complementary approachto classical techniques, such as test-bed experiments and simulation.One overall goal of this study is the demonstration that automated, formal andrigorous analysis of real-world protocols is possible and can be achieved in a rathershort period of time. Our model covers all core components of OLSR and abstractsfrom the optional features. At the moment, the project analyses fundamental behaviorsuch as packet delivery; the model guarantees that a packet which is injected into anetwork is _nally delivered at the destination. Moreover, the study veri_es that nodesin the network can _nd shortest paths to other nodes

MANETs: Internet Connectivity and Transport Protocols

A Mobile Ad hoc Network (MANET) is a collection of mobile nodes connected together over a wireless medium, which self-organize into an autonomous multi-hop wireless network. This kind of networks allows people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking is not a new concept, having been around in various forms for over 20 years. However, in the past only tactical networks followed the ad hoc networking paradigm. Recently, the introduction of new technologies such as IEEE 802.11, are moved the application field of MANETs to a more commercial field. These evolutions have been generating a renewed and growing interest in the research and development of MANETs. It is widely recognized that a prerequisite for the commercial penetration of the ad hoc networking technologies is the integration with existing wired/wireless infrastructure-based networks to provide an easy and transparent access to the Internet and its services. However, most of the existing solutions for enabling the interconnection between MANETs and the Internet are based on complex and inefficient mechanisms, as Mobile-IP and IP tunnelling. This thesis describes an alternative approach to build multi-hop and heterogeneous proactive ad hoc networks, which can be used as flexible and low-cost extensions of traditional wired LANs. The proposed architecture provides transparent global Internet connectivity and address autocofiguration capabilities to mobile nodes without requiring configuration changes in the pre-existing wired LAN, and relying on basic layer-2 functionalities. This thesis also includes an experimental evaluation of the proposed architecture and a comparison between this architecture with a well-known alternative NAT-based solution. The experimental outcomes confirm that the proposed technique ensures higher per-connection throughputs than the NAT-based solution. This thesis also examines the problems encountered by TCP over multi-hop ad hoc networks. Research on efficient transport protocols for ad hoc networks is one of the most active topics in the MANET community. Such a great interest is basically motivated by numerous observations showing that, in general, TCP is not able to efficiently deal with the unstable and very dynamic environment provided by multi-hop ad hoc networks. This is because some assumptions, in TCP design, are clearly inspired by the characteristics of wired networks dominant at the time when it was conceived. More specifically, TCP implicitly assumes that packet loss is almost always due to congestion phenomena causing buffer overflows at intermediate routers. Furthermore, it also assumes that nodes are static (i.e., they do not change their position over time). Unfortunately, these assumptions do not hold in MANETs, since in this kind of networks packet losses due to interference and link-layer contentions are largely predominant, and nodes may be mobile. The typical approach to solve these problems is patching TCP to fix its inefficiencies while preserving compatibility with the original protocol. This thesis explores a different approach. Specifically, this thesis presents a new transport protocol (TPA) designed from scratch, and address TCP interoperability at a late design stage. In this way, TPA can include all desired features in a neat and coherent way. This thesis also includes an experimental, as well as, a simulative evaluation of TPA, and a comparison between TCP and TPA performance (in terms of throughput, number of unnecessary transmissions and fairness). The presented analysis considers several of possible configurations of the protocols parameters, different routing protocols, and various networking scenarios. In all the cases taken into consideration TPA significantly outperforms TCP