Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 5 Articles
Packet filtering and processing rules management in firewalls and security gateways has become commonplace in increasingly\ncomplex networks. On one side there is a need to maintain the logic of high level policies, which requires administrators to\nimplement and update a large amount of filtering rules while keeping them conflict-free, that is, avoiding security inconsistencies.\nOn the other side, traffic adaptive optimization of large rule lists is useful for general purpose computers used as filtering devices,\nwithout specific designed hardware, to face growing link speeds and to harden filtering devices against DoS and DDoS attacks. Our\nwork joins the two issues in an innovative way and defines a traffic adaptive algorithm to find conflict-free optimized rule sets,\nby relying on information gathered with traffic logs. The proposed approach suits current technology architectures and exploits\navailable features, like traffic log databases, to minimize the impact of ACO development on the packet filtering devices. We\ndemonstrate the benefit entailed by the proposed algorithm through measurements on a test bed made up of real-life, commercial\npacket filtering devices....
Recently wireless sensor network (WSN) has become one of the most interesting networking technologies, since it can be deployed\nwithout communication infrastructures. A sensor network is composed of a large number of sensor nodes; these nodes are\nresponsible for supervision of the physical phenomenon and transmission of the periodical results to the base station. Therefore,\nimproving the energy efficiency and maximizing the networking lifetime are the major challenges in this kind of networks. To deal\nwith this, a hierarchical clustering scheme, called Location-Energy Spectral Cluster Algorithm (LESCA), is proposed in this paper.\nLESCA determines automatically the number of clusters in a network. It is based on spectral classification and considers both the\nresidual energy and some properties of nodes. In fact, our approach uses the K-ways algorithm and proposes new features of the\nnetwork nodes such as average energy, distance to BS, and distance to clusters centers in order to determine the clusters and to\nelect the cluster�s heads of aWSN. The simulation results show that if the clusters are not constructed in an optimal way and/or the\nnumber of the clusters is greater or less than the optimal number of clusters, the total consumed energy of the sensor network per\nround is increased exponentially....
The intrusion detection application in a homogeneous wireless sensor network is defined as a mechanism to detect unauthorized\nintrusions or anomalous moving attackers in a field of interest. The quality of deterministic sensor nodes deployment can be\ndetermined sufficiently by a rigorous analysis before the deployment.However, when randomdeployment is required, determining\nthe deployment quality becomes challenging. An area may require that multiple nodes monitor each point from the sensing area;\nthis constraint is known as k-coverage where k is the number of nodes. The deployment quality of sensor nodes depends directly\non node density and sensing range; mainly a random sensor nodes deployment is required.The major question is centred around\nthe problem of network coverage, how can we guarantee that each point of the sensing area is covered by the required number of\nsensor nodes and what a sufficient condition to guarantee the network coverage? To deal with this, probabilistic intrusion detection\nmodels are adopted, called single/multi-sensing detection, and the deployment quality issue is surveyed and analysed in terms of\ncoverage.We evaluate the capability of our probabilisticmodel in homogeneous wireless sensor network, in terms of sensing range,\nnode density, and intrusion distance....
Two main concerns for designing a wireless system are more network capacity and less energy consumption. Recently, distributed\nantenna system (DAS) has received considerable attention due to its potential to provide higher spectral efficiency (SE) and uniform\ncoverage for cellular networks. In this regard, this paper compares the performance of DAS with centralized antenna system (CAS)\nin LTE-A system in terms of energy efficiency (EE), where practical restrictions such as out-of-cell interference, path loss, and small\nscale fading are taken into account. Furthermore, the EE and system power consumption are investigated under three different\ncell-load scenarios (high, moderate, and low load) where different numbers of antennas are activated and remaining of antennas\nare under sleep mode. Finally, based on the tradeoff between power-saving and EE, two optimal DAS antenna deployments are\nproposed for low and moderate cell-load scenarios. The results reveal that DAS considerably outperforms CAS in terms of EE\nand by optimal deploying antennas of DAS significant power-saving and EE are achievable. The proposed methodology achieved\nsavings of up to 27.63% in terms of energy savings in a macrocell with guarantee of a high capacity of data....
Congestion control in wireless networks is strongly dependent on the dynamics and instability of wireless links. Therefore, it is\nvery difficult to accurately evaluate the characteristics of the wireless links. It is known that TCP experiences serious performance\ndegradation problems inwireless networks.Moreover, congestion control mechanisms that rely on network interaction and network\nparameters, such as XCP and RCP, do not evaluate accurately the capacity and available link bandwidth in wireless networks. In\nthis paper we propose new explicit flow control protocols for wireless mesh networks, based on XCP and RCP. We name these\nprotocols XCP-Winf and RCP-Winf. They rely on the MAC layer information gathered by a new method to accurately estimate the\navailable bandwidth and the path capacity over a wireless network path. The estimation is performed in real time and without the\nneed to intrusively inject packets in the network. These new congestion control mechanisms are evaluated in different scenarios in\nwireless mesh and ad hoc networks and compared against several new approaches for wireless congestion control. It is shown that\nboth XCP-Winf and RCP-Winf outperform the evaluated approaches, showing its stable behavior and better channel utilization....
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