Fault Tolerance in Application-Level Multicast Networks

Overlay multicast (Application-Level Multicast (ALM)) constructs a multicast delivery tree among end hosts. Unlike traditional IP multicast where the internal tree nodes are dedicated routers which are relatively stable and do not leave the multicast tree voluntarily, the non-leaf nodes in the overlay tree are free end hosts which can join/leave the overlay at will, or even crash without notification. So, the leaving node can leave suddenly and cannot give its descendants (and the Rendez-vous Point (RP)) the time to prepare the recovering (the reconnection) of the overlay tree, and so there is a need to trigger a rearrangement process in which each one of its descendants should rejoin the overlay tree. In this case, all of its downstream nodes are partitioned from the overlay tree and cannot get the multicast data any more. These dynamic characteristics cause the instability of the overlay tree, which can significantly impact the user. A key challenge in constructing an efficient and resilient ALM protocol is to provide fast data recovery when overlay node failures partition the data delivery paths. In this paper, we analyze the performance of the ALM tree recovery solutions using different metrics.

Study of DDOS Attack Impact on Vehicular Ad Hoc Network in City

Distributed Denial of Service attack (DDOS) on Vehicular Ad Hoc Networks (VANETs) is considered to be one of the most serious types of attacks that can be targeted to those networks. The danger of this attack is in the difficulty of detection because of the cooperation of several attacking nodes in the network, and its impact on the availability requirement that is one of the most important security requirements in a network offering real-time applications .In our research, we study the effect of this attack on VANET network in the city, taking into consideration two cases. In the first case the target of the attack is the nodes, while in the second one, the target is the road side units (RSU). Simulation results have shown that this attack has a significant impact on both cases, by comparing the basic parameters of the network, such as throughput in/out and the number of dropped packets, before and after the attack.

Performance Study of APS Algorithm for position Determination in Underwater Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are often deployedrandomly;this makes the positiondetermination of deployed nodes a very difficult issue, which is called localization problem. The importance of node localization information becomes from the facility of routing operation and the network control, that makes the network works correctly. Nowadays, Global Position System (GPS) is appeared as the most important position system, but it is inapplicable for the low-cost self-configure sensor networks, and also it is impossible to install GPS for each sensor nodebecause of high cost, large volume and high complexity required of adding it to nodes, especially for large network.Therefore, a few number of nodes may be configured with GPS. In this paper,we will study the localization algorithmAd-hoc Positioning System (APS) algorithmused inUnderwater WSN, andwill testthe effectiveness of usingitin determining the node position based on the distance calculated by anchor nodes. These nodes are the nodes which know their positions.

Performance Evaluation for GPSR and AODV routing protocols at the junctions in VANET

A Vehicular Ad-hoc Network (VANET) is a collection of nodes forming a wireless network, but the nodes of this network are vehicles with special equipment that enable them to communicate with each other. VANET protocols have to face high challenges due to dynamically changing topologies, link breakage and low vehicular density. A suitable and effective routing protocol helps to ensure that messages are reached to their destinations and achieve the desired aim of the application. In this research, we present an analysis of the performance of two major routing protocols used in these networks, which are AODV (Ad hoc On-Demand Distance Vector) and GPSR (Greedy Perimeter Stateless Routing). This analysis is based on various parameters such as end-to-end delay and average dropped packets, in order to find the best protocol which can be used in the network with low density at the junctions. To achieve this purpose, we used a simulator OPNET_17.5. Depending on the simulation results, we have obtained and the analysis and comparison of two protocols at different low density contract. We found that GPSR protocol has better performance end-to-end delay and average dropped packets are used as the performance metrics, and is better for VANET under the low vehicular density simulation scenario at junctions.

A New Fault Tolerance Protocol in Application-Level Multicast Networks

Application-Level Multicast Networks are easy to deployment, it does not require any change in the network layer, where data is sent to the network via the built-up coverage of the tree using a single-contact transmission of the final contract, who are the hosts are free can join / leave whenever they want it, or even to leave without telling any node so. Causing the separation of the children of the leaved node from the tree, and the request for rejoin, in other words, these nodes will be separated from the overlay tree and cannot get the data even rejoin. This causes the distortion of the constructed tree, and the loss of several packets which can significantly impact the user. One of the key challenges in building a multi-efficiently and effectively overlay multicast protocol is to provide a robust mechanism to overcome the sudden departure of a node from the overlay tree without a significant impact on the performance of the constructed tree. In this research, we propose a new protocol to solve problems presented previously.

Dynamic Black List (DBL) algorithm to defense against DDoS attack in Vehicular Ad-hoc Network

A Vehicular Ad-hoc Network (VANET) is a group of vehicles, which have special equipments enable them to connect with each other as a wireless network .The attacks are considered as the most serious challenge against this network, especially those targeting availability requirement, which is one of the most important security requirements in VANET. The Denial of Service (DoS) and Distributed Denial of Service (DDoS) attacks are the most important attacks since they make the network not available for actual users. In this research, we present an algorithm to detect and face the DDoS attack. This algorithm depends on a black list contains the IDs for malicious vehicles, which are being chosen depending on a certain threshold value for a number of messages received from them. We analyze the algorithm performance depending on throughput, packet delivery ratio, end to end delay parameters, and compare it with the performance of the Queue Limiting Algorithm (QLA) .To achieve this purpose, we use NS2.35 simulator using details to support Wireless Access in Vehicular Environments (WAVE). The simulation results showed that the proposed algorithm reduces the effect of the attack Significantly since it increases the throughput and packet delivery ratio.

Enhancend Secure Data Aggregation In Mobile Wireless Sensor Networks (MWSNs)

Mobile Wireless Sensor Network (MWSN) is an emerging technology for attraction of researchers with its research advantage and various application domains. Due to limited resources of sensor nodes such as transmission power, communication capability and size of memory, data aggregation algorithms are the most practical technique that reduces large amount of transmission in this network. Security is an important criterion to be considered because, wireless sensor nodes are deployed in a remote or hostile environment area that is prone to attacks easily. Therefore, security are essential issue for MWSN to protect information against attacks. In this research, we offered an algorithm of secure data aggregation in MWSN based on pair-wise keys technology and hash function. We studied important parameters such as execution time, end-to-end delay and number of storied keys. Results showed that

Studying the ARP Spoofing Attack Effect on SDN Networks

The mapping of Layer 3 (IP) to Layer 2 (MAC) addresses is a key service in IP networks, and is achieved via the Address Resolution Protocol (ARP) protocol in IPv4. Due to its stateless nature and lake of authentication, ARP is an easy goal to spoofing attacks, which can enable Denial of Service (DoS) or Man-in-the-Middle (MIM) attacks. In this search, we discuss the problem of ARP spoofing in the context of Software Defined Networks (SDNs). We studied important parameters such as throughput, delay and the availability of the network. Results showed that ARP spoofing attacks was able to make a negative effects on network performance

Performance Evaluation of Asymmetric Encryption Algorithm (MQQ-ENC) in Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Network (WMSN) consists of a large number of small size, low power, limited sources sensor nodes, deployed in tested field, These nodes have the ability of sensing, processing, storing and sending multimedia data from the tested field in real time. The security in WMSNs is one of most important issues that should be studied due to the special nature of this network, and of the importance of inquest basic security requirements when sending information in the network. Using cryptography technics are very effective ways to realize basic security requirements in this network. The recently proposed MQQ algorithm is one of public key cryptography (PKC) algorithms, which provides a good performance compared to other PKC algorithms. In this research, we present an analyzing study of MQQ implementation in WMSNs. To achieve our goal, we used real images taken by multimedia wireless sensor nodes. We studied the most important parameters such as the size of generated keys and encrypted images, the execution time and the space occupied in the flash memory of multimedia wireless sensor nodes and complexity degree of this algorithm. Results showed that MQQ has good performance, as well as the execution time of operations is better than RSA algorithm. Results also showed the importance of taking into account a large size of public key of MQQ algorithm when implementation it in WMSNs.