In some scenarios, smart mobile devices do not have access to any fixed network infras- tructures. In order to accomplish an assigned task the devices should be connected to each other in an ad hoc manner. In these scenarios, there is no pre-existing network infrastructure 1
Figure 1.1: Infrastructure based wireless network to rely on. Responsibility for providing network connectivity is shared by all the mobile de- vices. For example, in military battle fields, there is no pre-existing network infrastructure; If troops or military equipment need to be connected to each other to conduct a mission, they need to form an ad hoc network. These types of ad hoc networks are infrastructure-less wireless networks. An infrastructure-less wireless network is illustrated in Figure 1.2. Ad hoc networks are decentralized types of wireless networks. In this type of network, nodes should cooperatively form the network and manage all the connectivity issues. In most cases, it is desirable that the network can operate and accomplish its mission without any central entity. Trying to have a network managing mechanism without any central entity is a step toward having a truly distributed system. In the majority of ad hoc networks’ applications, nodes are not stationary. Nodes change their positions in the network. While they are moving, they need to stay connected to the network. This type of mobile ad hoc networks are categorized as MANET . Lack of centralized management entity, mobility, and wireless communication makes MANET susceptible to a variety of security attacks. With advances in wireless communication and proliferation of mobile devices, researchers try to investigate the different security solutions for MANETs in order to make them capable of delivering reliable services. 2
Figure 1.2: Infrastructure less wireless network 1.1 MANET characteristics and applications Mobile ad hoc networks are a collection of mobile devices, equipped with wireless technologies that form a network without any central administrative entity . In this type of network, nodes can communicate with each other directly or through other nodes without using any central entity to manage the connections. In a MANET, nodes acts as hosts and routers. Node mobility causes frequent network topology changes and routing protocols should be capable of maintaining connectivity in such a dynamic environment. Some of the most important characteristics of MANET are as follows : • As a result of wireless communication links, MANETs have lower bandwidth capacity in comparison to wired networks; they are subject to jamming, signal fading and interference ; • In MANETs, nodes usually depend on battery power. Thus nodes should perform their tasks in the most energy efficient manner; • Because of wireless links and absence of central entities, security in MANETs can easily be compromised. Wireless nodes are vulnerable to eavesdropping and jamming.
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- Fall '19
- Test, Computer network, routing protocol, MANETs