Building an IP-based community wireless mesh network: Assessment

Wireless mesh networks are experiencing rapid progress and inspiring numerous applica tions in different scenarios, due to features such as autoconfiguration, self healing, connec tivity coverage extension and support for dynamic topologies. These particular characteristics make wireless mesh networks an appropriate architectural basis for the design of easy to deploy community or neighbourhood networks. One of the main chal lenges in building a community network using mesh networks is the minimisation of user intervention in the IP address configuration of the network nodes. In this paper we first consider the process of building an IP based mesh network using typical residential rou ters, exploring the options for the configuration of their wireless interfaces. Then we focus on IP address autoconfiguration, identifying the specific requirements for community mesh networks and analysing the applicability of existing solutions. As a result of that analysis, we select PACMAN, an efficient distributed address autoconfiguration mechanism origi nally designed for ad hoc networks, and we perform an experimental study using off the shelf routers and assuming worst case scenarios analysing its behaviour as an IP address autoconfiguration mechanism for community wireless mesh networks. The results of the conducted assessment show that PACMAN meets all the identified requirements of the community scenario.European Community´s Seventh Framework ProgramPublicad

Experimental evaluation of the usage of ad hoc networks as stubs for multiservice networks

This paper describes an experimental evaluation of a multiservice ad hoc network, aimed to be interconnected with an infrastructure, operator-managed network. This network supports the efficient delivery of services, unicast and multicast, legacy and multimedia, to users connected in the ad hoc network. It contains the following functionalities: routing and delivery of unicast and multicast services; distributed QoS mechanisms to support service differentiation and resource control responsive to node mobility; security, charging, and rewarding mechanisms to ensure the correct behaviour of the users in the ad hoc network. This paper experimentally evaluates the performance of multiple mechanisms, and the influence and performance penalty introduced in the network, with the incremental inclusion of new functionalities. The performance results obtained in the different real scenarios may question the real usage of ad-hoc networks for more than a minimal number of hops with such a large number of functionalities deployed

Design and Implementation of ID Based MANET Autoconfiguration Protocol

Auto-configuration protocols are used for assignment of unique IP addresses to nodes in Mobile ad hoc networks. Without the assignment of unique IP addresses, service provisioning between the nodes is not possible. Such protocols use various heuristics to ensure the uniqueness in IP address assignment; such aspects increase the overall complexity in MANET system design. Moreover the overriding role of IP address as an ID in Application layer and Locator in routing space is a bottleneck in future wireless network (FWN) design. Contemporary FWN research is focusing on ID/Locator split concept designs. In this paper we propose an ID/Locator based architecture for MANETs which also solves               auto-configuration requirements for MANETs. Our proposed architecture is an adaptation from available ID/Locator split concepts for infrastructure oriented networks for usage in MANET context. The designed protocol uses identifiers for node identification, node discovery and traffic flow between end points. The protocol support provision for running contemporary IP oriented services. We have also verified various use cases of our proposed protocol through Linux based implementation

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

Internet connection method for mobile ad hoc wireless networks

In recent years, wireless networks with Internet services have become more and more popular. Technologies which integrate Internet and wireless networks have extended traditional Internet applications into a more flexible and dynamic environment. This research work investigates the technology that supports the connection between a Mobile Ad Hoc Wireless Network (MANET) and the Internet, which enables the current wireless Internet technologies to provide a ubiquitous wireless life style. With detailed analysis of the existing wireless Internet technologies and MANETs regarding their features and applications, the demand and lack of research work for an application to provide Internet connection to MANET is indicated. The primary difficulty for MANET and Internet connection is that the dynamic features of MANET do not suit the traditional connection methods used in infrastructure wireless networks. This thesis introduces new concept of the 'Gateway Awareness' (GAW) to the wireless devices in the MANET. GAW is a new routing protocol designed by the author of this thesis, at the University of Warwick. Based on GAW, an inclusive definition for the connection method, which supports the Internet connection and keeps the independency of routing in MANET, is addressed. Unlike other research work, this method supports the MANET and Internet communication in both directions. Furthermore, it explores possible ways of using the Internet as an extension for wireless communications. The GAW routing method is developed from destination sequenced distance vector (DSDV) routing protocol. However, it defines a layer of wireless nodes (known as GAWNs) with exclusive functions for the Internet connection task. The layer of GAWNs brings a new set of route update and route selection method. Simulations show that the GAW routing method provides quality Internet connection performance in different scenarios compared with other methods. In particular, the connection is completed with minimum effect on the independent MANET while the routing efficiency and accuracy is guaranteed

Efficient address auto-configutation in ad hoc networks - protocol & algorithms

Mobile Ad hoc NETworks (MANETs) are an important part of mobile communications as they allow communications without the presence of an infrastructure. A MANET consists of an autonomous system of mobile devices. In contrast with infrastructure networks, MANET nodes act as hosts as well as routers. In the Internet, multi-hop communications are supported by the network layer, i.e. the Internet Protocol (IP). However, this requires the availability of a unique IP address. Due to the dynamic and decentralized nature of MANETs, and especially due to the mobility of nodes, providing and maintaining this unique IP address automatically in a decentralized way is a challenge addressed by auto-configuration protocols as part of the network layer. Several protocols to support this in fully decentralized environments as present in MANETs have been developed, e.g., the MANETConf, Buddy and Prophet protocols. However, they fail to solve the problem efficiently in scenarios where the nodes are highly mobile, e.g., as is the case with typical car-to-car applications. This thesis presents an address auto-configuration protocol that efficiently supports highly dynamic mobile ad hoc networks. This protocol, the Logical Hierarchical Addressing (LHA) protocol, focuses on the fast assigning of IP addresses to new nodes joining a MANET while minimizing the signaling overhead. Besides this, LHA introduces a solution for the merging problem ensuring, the uniqueness of IP addresses in the network when two previously independent MANETs merge. LHA is based on the idea that the address assignments can be achieved locally by the neigh-boring nodes of a requester, which in turn leads to a fast address assignment. Basically, in LHA, each configured node in a MANET is able to select, allocate and assign a unique address to a new node requesting an address that is free. By dividing the address space logically among configured nodes LHA is able to build a number of hierarchical structures of IP addresses. By this means, LHA solves efficiently the merging problem. Furthermore, the utilization of a certain assignment algorithm and specific address data structures is the key that LHA is able to solve the problem of missing IP addresses due to the departure of nodes. Because LHA is less dependent on unicast connections it reduces the signaling overhead and achieves fast address assignment. This in turn makes LHA highly suitable to the use in a wide range of scenarios, especially in those which are high mobility.Mobile Ad-Hoc-Netzwerke (MANETs) sind ein bedeutender Teil der Mobilkommunikation, da sie Kommunikation ohne das Vorhandensein von Infrastruktur erlauben. Ein MANET besteht aus einem autonomen System von mobilen Geräten. Im Gegensatz zu Infrastruktur-Netzwerken agieren MANET-Knoten als Host, ebenso wie als Router. Im Internet werden Multi-Hop-Kommunikationen durch den Netzwerk-Layer unterstützt, z.B. das Internet Protokoll (IP). Dies verlangt jedoch die Verfügbarkeit einer eindeutigen IP-Adresse. Wegen der dynamischen und dezentralen Natur von MANETs und besonders wegen der Mobilität der Knoten, ist die automatische, dezentrale Bereitstellung und Verwaltung dieser eindeutigen IP-Adresse eine Herausforderung, die durch Autokonfigurationsprotokolle als Teil des Netzwerk-Layers gelöst werden soll. Zur Unterstützung dieser dezentralen Umgebung, die durch MANET repräsentiert werden, wurden verschiedene Protokolle entwickelt, wie MANETConf, Buddy und Prophet. Allerdings verfehlen sie eine effiziente Lösung des Problems in Szenarien mit hoch-mobilen Knoten, wie z.B. bei typischen "Auto-zu-Auto"-Anwendungen. Die vorgestellte Arbeit präsentiert ein Adressenautokonfigurationsprotokoll, das hoch dynamische mobile Ad-Hoc-Netzwerke unterstützt. Dieses Protokoll, genannt "Logical Hierarchical Addressing (LHA)", konzentriert sich auf die schnelle Zuweisung von IP-Adressen für neue Knoten, die einem MANET beitreten, und minimiert gleichzeitig den Signal-Overhead. Zusätzlich stellt LHA eine Lösung zum Vereinigungsproblem von Netzwerken vor und sichert die Eindeutigkeit von IP-Adressen, wenn sich 2 vorher unabhängige MANETs vereinigen. LHA basiert auf der Idee, dass die Adresszuweisung lokal durch jeden benachbarten Knoten eines anfragenden Knotens durchgeführt werden kann, was zusätzlich zu einer schnelleren Adresszuweisung führt. In LHA kann jeder konfigurierte Knoten in einem MANET für einen neuen Knoten eine eindeutige, freie Adresse auswählen und zuweisen. Durch die logische Aufteilung des Adressbereiches zwischen den konfigurierten Knoten kann LHA eine Anzahl hierarchischer Strukturen von IP-Adressen aufbauen, wodurch LHA das Vereinigungsproblem effektiv löst. Des Weiteren ist der Einsatz eines speziellen Zuweisungsalgorithmus und spezieller Adressdatenstrukturen der Schlüssel dafür, das LHA das Problem der durch das Verschwinden von Knoten fehlenden IP-Adressen lösen kann. Da LHA weniger abhängig von Unicast-Verbindungen ist, reduziert es den Signal-Overhead und erreicht eine schnelle Adresszuweisung. Dieser Effekt bewirkt die hohe Eignung von LHA für eine Vielzahl von Szenarien, insbesondere hoch mobile Umgebungen