Catálogo de publicaciones - libros

In wireless mesh networks, there are mesh routers which can compose a wireless backbone with low mobility. We propose a hop-by-hop multipath routing scheme which is suitable for mesh routers offering network reliability with route redundancy. We extend DSDV in order to have multiple next hops to all nodes in the network without additional overheads. The basic idea of our scheme is to make several paths between the source and destination by selecting a proper next hop at every forwarding data. We choose a mesh router with the highest residual bandwidth as a next hop among multiple ones. Through periodic one hop broadcasting, not only we can get residual bandwidth information but also we can detect route failures fast and reduce the number of routing overhead packets. Through simulation, we represent that our scheme is more efficient than DSDV in delivering data to the destination when traffic is heavy, reducing overhead packets in the network, and preventing data loss when the route failure occurs.

In this paper, we address clustering in ad hoc networks. Ad hoc networks are a wireless networking paradigm in which mobile hosts rely on each other to keep the network connected without the help of any pre-existing infrastructure or central administrator. Thus, additional features pertinent to this type of networks appeared. In fact, centralized solutions are generally inadaptable due to the need for cooperative network operations. To ensure efficient, tolerant and durable cooperative operations, nodes need to organize themselves. Clustering is an organization method which consists in grouping the nodes into clusters (groups) managed by nodes called clusterheads. In this paper, we present existing clustering algorithms and propose a new solution inspired from two of these algorithms (Lowest Id and WCA). This solution, called Lowest Weight, exploits their advantages and relieve to their drawbacks in terms of clusters stability and computational overhead. Simulation experiments were conducted to evaluate the performance of the algorithm proposed in terms of clusters numbers, clusterheads lifetime and the number of reaffiliations (node moving from a cluster to another). Results show that Lowest Weight ameliorate performs of existing algorithms especially regarding mobility leading to more suitable, adaptable, scalable and autonomous clustering.

Wireless Mesh Networks (WMNs) are evolving to be the key technology of the future. The self-configuring nature of WMNs and the ease, with which a mesh router/mesh point can be added, makes it pertinent to ensure their secure operation. All the routing protocols in WMNs naively assume the nodes to be co-operative in forwarding each other’s packets. However, a node can behave selfishly by discretely dropping other’s packets, in an attempt to maximize its throughput. In this paper, we present a distributed scheme called, Distributed Self-policing Architecture for Fostering Node Cooperation (D-SAFNC), for enforcing cooperation among the nodes in a WMN. We use a distributed approach in isolating any selfish node with the help of localized detection agents called sink nodes. We study the effectiveness of our scheme through simulations using ns-2 which reaffirm that D-SAFNC can successfully prevent any performance degradation due to the presence of selfish nodes.

Low-cost Radio Frequency Identification (RFID) tags affixed to consumer items as smart labels are emerging as one of the most pervasive computing technology in history. This can have huge security implications. The present article surveys the most important technical security challenges of RFID systems. We first provide a brief summary of the most relevant standards related to this technology. Next, we present an overview about the state of the art on RFID security, addressing both the functional aspects and the security risks and threats associated to its use. Finally, we analyze the main security solutions proposed until date.

GSM is the most popular standard for mobile phones in the world. In spite of the tremendous market growth, however, the GSM system has the fatal security problems in TMSI allocation protocol. These problems are right user authentication and location privacy. In this paper, we propose the secure TMSI allocation mechanism using the certification concept to solve these problems. The proposed mechanism provides partial anonymity, which has been rarely provided in the other approaches. Also we propose the modified mechanism to reduce TMSI allocation procedure without changing of the architecture of the original GSM system.

Manet security has a lot of open issues. Due to its characteristics, this kind of network needs preventive and corrective protection. In this paper, we focus on corrective protection proposing an anomaly IDS model for Manet. The design and development of the IDS are considered in our 3 main stages: normal behavior construction, anomaly detection and model update. A parametrical mixture model is used for behavior modeling from reference data. The associated Bayesian classification leads to the detection algorithm. MIB variables are used to provide IDS needed information. Experiments of DoS and scanner attacks validating the model are presented as well.

We present a family of self-stabilizing distributed algorithms to built a spanning tree on the underlaying communications graph of an adhoc wireless network. Next, based on this principle, we show how to construct two overlaying trees which are suitable for routing tasks.

In order to provide the multicast service in MANET, a lot of multicast routing protocols have been proposed. Most of them create tree or mesh-based graphs and require network nodes over the tree or mesh to maintain the membership information. In particular, high node mobility causes the tree or mesh to be broken and reconstructed by generating much overhead to manage the membership at network nodes. In accordance with overlay multicast protocols to reduce such overhead, which enables the packet transmission regardless of the movement of intermediate nodes over the paths between group members, we propose an overlay small group multicast mechanism, called SPM (Shortest Path overlay Multicast) for MANET. SPM multicasts packets over the shortest paths from a source to each group member without duplicate packet delivery over common partial paths. When creating a multicast overlay tree, SPM utilizes the route information provided by ad hoc unicast routing protocol without further control messages and any other information. Extensive simulations through NS-2 simulator proved that SPM has better throughput, loss rate and packet transmission delay than MAODV, a typical tree based multicast routing protocol used in MANET.

Mobile devices of new generation are able to connect to multiple networks and to constitute new infrastructureless networks. These dynamic environments require new security paradigms and automatic mechanisms to minimize user intervention. Our goal is the definition of a new concept of distance that considers the current domain constraints and the user preferences. This paper addresses some of the problems of these complex environments by using Multidimensional Scaling (MDS) techniques. We also propose collaborative mechanisms for automatic environment marking. Based on these ideas we have developed PervsIM, a decision mechanism that selects the most appropriate network or peer to interact with. Besides we have defined an embedded access control module which ensures that PervsIM decisions are followed by all applications. Furthermore, several simulation results and implementation details outline how these results can be incorporated in today’s mobile devices.

The secure operation of the routing protocol is one of the major challenges to be met for the proliferation of the Mobile Ad Hoc networking (MANET) paradigm. Secure Global State Routing Protocol (SGSR) proposed here defines some rules to ensure secure neighbor discovery. Priority is introduced to prevent denial of service attacks. SGSR also can limit the packet in a certain area. So it can be employed as a stand-alone protocol, or fit naturally into a hybrid routing framework. This paper provides formal analysis to illuminate that SGSR is robust against individual attackers. The simulation result shows that the efficiency and the cost of the protocol are in an acceptable scope after adding the secure mechanisms.