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This paper shows how Multi-Topology routing can be used in highly heterogeneous tactical mobile ad hoc networks to improve the network resource utilization. We suggest the usage of a QoS model where a routing protocol maintains several, distinctive network topologies. Each topology is tailored to support either single or multiple QoS-classes. With this model, traffic flows requiring a QoS-class that...
The problem of burst losses in OBS networks has an impact on the service quality perceived by end users. In order to guarantee certain level of Service Quality (QoS) in terms of burst losses, wavelength resources have to be dimensioned properly. In this paper, we address the problem of the Virtual Topology (VT) design that concerns the establishment of explicit routing paths and the allocation of...
The capacity of a multi-hop wireless network is the traffic payload that it can transport. This is a prominent quality of service issue, particularly in the highly constrained settings of 802.11 wireless mesh network. In this paper, we consider two complementary definitions of the capacity. A network-wise capacity is defined as the sum of the upload traffic, and a flow- wise capacity highlighting...
Wireless ad hoc networks using omni-directional antennas do not scale well due to interference between nearby nodes. Maintaining the QoS of the communications in this type of network is a difficult task. Using multiple narrow beam directional antennas alleviates this problem at the expense of connectivity. Multi-beam smart antennas allow the network topology to be adjusted dynamically by adjusting...
OPNET has been widely used as a network simulator, but not much emphasis has been given on the performance of this simulator for ZigBee wireless sensor networks (WSN). Simulation of WSNs is a challenging task due to the nature of hardware design, energy limitations, and deployment of a vast number of nodes. An inclusive study and analysis of the QoS performance evaluation of the ZigBee protocol within...
The current Internet infrastructure is facing a number of limitations that is not suitable to meet the growing number of services and users. In particular, one aspect that requires enhancement is routing, where original routing concepts were designed for static traffic patterns with minimal variations and supporting mainly low throughput traffic (e.g. Data). As the number of users as well as services...
Wireless ad hoc networks are self-configurable distributed systems. One of the major problems in traditional wireless ad hoc networks is interference. The interference could be reduced using smart directional antennas. In this study, multibeam smart antennas have been used. When using this type of antenna, two nodes can communicate when both the sending and receiving beams are pointing towards each...
A multimetric QoS routing protocol (MQOLSR) is proposed in this paper, which providing different QoS for different applications flow in an ad hoc network. The protocol, which integrates QoS measurement and packet forwarding, expands the topology discovery and routing computing mechanism of the OLSR protocol. It can provide different routing and forwarding service according to different application...
As wireless local area networks (WLAN) become ubiquitous and an integral part of data networks, they will also be increasingly used for applications ranging from standard Internet services like ftp to time bound multimedia applications, such as Voice (or Video) over IP (VoIP/VIP), HDTV etc. with strict latency, throughput or jitter restrictions. These applications on WLAN will also be more bandwidth...
This paper describes the identification of potential problems with ad hoc routing protocol that contribute to the overall performance. Another major factor that contributes to routing protocol performance is when wireless nodes move out of coverage area of the other nodes and thus lose connection, or the opposite, where other wireless nodes join the network while on the move and require a dynamic...
In wireless sensor networks (WSNs) used in monitoring applications, the need to provide real-time traffic with an appropriate QoS typically clashes with the energy consumption constraints of the nodes, which have to work for long periods without the possibility of replacing their batteries. When both energy and QoS constraints are present, the role of topology control mechanisms is fundamental. This...
Due to vast use of network centric environments in critical applications, reliability and availability are the essential characteristics of these networks. A fundamental requirement is the ability to keep the relation between the network elements even in any malfunctions in network topology. Rerouting is a suitable response to this issue. In this paper, we consider several retrieval and rerouting...
The IEEE 802.15.4 and ZigBee protocol stack offers great potentials for ubiquitous and pervasive computing, namely for wireless sensor networks. However, there are still some open and ambiguous issues that turn its practical use a challenging task. One of those issues is the study of low power consumption of sensor device, which is the biggest issue in sensor network, still has many unresolved issues...
Grid technology has been developed rapidly in recent years. To gain reliable quality of service, grid network service concept is introduced to evaluate network performance. It is the first and important step for Grid users to transparently locate the resources to be used. The paper discusses the topology discovery service in grid network. In this paper, we present a novel algorithm (SBI) for discovering...
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