105 research outputs found
Performance Evaluation of Reactive Routing Protocols in MANETs in Association with TCP Newreno
We inspect the performance of TCP NewReno protocol for data transfer in Mobile Ad hoc networks (MANETs). Dynamic Source Routing (DSR) protocols and AdHoc On-demand Distance Vector (AODV) are standard reactive routing protocols widely used in MANETs. In addition we also have to consider Transmission Control Protocol (TCP) as essential for MANETs since it is one of the widely used internet protocol for dependable data transmission. TCP has its variants namely TCP Reno, TCP NewReno , TCP Vegas and TCP SACK. In this paper we are evaluating the performance of DSR and AODV in association with TCP Newreno with respect to various parameters such as Average throughput, instant throughput, residual energy, packet delivery ratio. The ns-2 network simulator was used for simulation
SecMon: end-to-end quality and security monitoring system
The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communication for the Internet users. This also applies to the Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by a limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guarantee makes the contemporary VoIP systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attack detection. Moreover, the SecMon approach represents a lowbandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above-mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement results. Furthermore, these metrics are aggregated in a reputation system that enables best route path selection in the P2P network. The reputation system helps also to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network
Safe Routing Approach by Identifying and Subsequently Eliminating the Attacks in MANET
Wireless networks that are decentralized and communicate without using
existing infrastructure are known as mobile ad-hoc networks. The most common
sorts of threats and attacks can affect MANETs. Therefore, it is advised to
utilize intrusion detection, which controls the system to detect additional
security issues. Monitoring is essential to avoid attacks and provide extra
protection against unauthorized access. Although the current solutions have
been designed to defeat the attack nodes, they still require additional
hardware, have considerable delivery delays, do not offer high throughput or
packet delivery ratios, or do not do so without using more energy. The
capability of a mobile node to forward packets, which is dependent on the
platform's life quality, may be impacted by the absence of the network node
power source. We developed the Safe Routing Approach (SRA), which uses
behaviour analysis to track and monitor attackers who discard packets during
the route discovery process. The attacking node recognition system is made for
irregular routing node detection to protect the controller network's usual
properties from becoming recognized as an attack node. The suggested method
examines the nearby attack nodes and conceals the trusted node in the routing
pathway. The path is instantly assigned after the initial discovery of trust
nodes based on each node's strength value. It extends the network's life span
and reduces packet loss. In terms of Packet Delivery Ratio (PDR), energy
consumption, network performance, and detection of attack nodes, the suggested
approach is contrasted with AIS, ZIDS, and Improved AODV. The findings
demonstrate that the recommended strategy performs superior in terms of PDR,
residual energy, and network throughput
Safe Routing in Ad Hoc Networks
Ad hoc mreže specifične su po svojim karakteristikama (necentraliziranost, samoorganiziranje i višeskokovnost). Zbog toga usmjerni protokoli u ad hoc mrežama moraju biti prilagođeni pojedinim primjenama mreže i zadovoljavati glavne zahtjeve - propusnosti, skalabilnost i sigurnost. U radu je prikazan pregled sigurnosti usmjeravanja u ad hoc mrežama. Navedena su svojstva ad hoc mreža i izazovi razvoja protokola usmjeravanja u njima. Opisani su glavni sigurnosni problemi u usmjeravanju i metode ispitivanja sigurnosti usmjernih protokola
Radio Communications
In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks
Hybrid token-CDMA MAC protocol for wireless networks.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2009.Ad hoc networks are commonly known to implement IEEE 802.11 standard as their medium
access control (MAC) protocol. It is well known that token passing MAC schemes
outperform carrier-sense-multiple-access (CSMA) schemes, therefore, token passing MAC
protocols have gained popularity in recent years. In recent years, the research extends the
concept of token passing ' scheme to wireless settings since they have the potential of
achieving higher channel utilization than CSMA type schemes.
In this thesis, a hybrid Token-CDMA MAC protocol that is based on a token passing scheme
with the incorporation of code division multiple access (CDMA) is introduced. Using a
dynamic code distribution algorithm and a modified leaky-bucket policing system, the
hybrid protocol is able to provide both Quality of Service (QoS) and high network resource
utilization, while ensuring the stability of a network. This thesis begins with the introduction
of a new MAC protocol based on a token-passing strategy. The input traffic model used in
the simulation is a two-state Markov Modulated Poisson Process (MMPP). The data rate
QoS is enforced by implementing a modified leaky bucket mechanism in the proposed MAC
scheme. The simulation also takes into account channel link errors caused by the wireless
link by implementing a multi-layered Gilbert-Elliot model. The performance of the proposed
MAC scheme is examined by simulation, and compared to the performance of other MAC
protocols published in the literature. Simulation results demonstrate that the proposed hybrid
MAC scheme is effective in decreasing packet delay and significantly shortens the length of
the queue.
The thesis continues with the discussion of the analytical model for the hybrid Token CDMA
protocol. The proposed MAC scheme is analytically modelled as a multiserver
multiqueue (MSMQ) system with a gated service discipline. The analytical model is
categorized into three sections viz. the vacation model, the input model and the buffer model.
The throughput and delay performance are then computed and shown to closely match the
simulation results. Lastly, cross-layer optimization between the physical (PHY) and MAC
layers for the hybrid token-CDMA scheme is discussed. The proposed joint PHY -MAC
approach is based on the interaction between the two layers in order to enable the stations to
dynamically adjust the transmission parameters resulting in reduced mutual interference and
optimum system performance
Cooperative routing for collision minimization in wireless sensor networks
Cooperative communication has gained much interest due to its ability to exploit the
broadcasting nature of the wireless medium to mitigate multipath fading. There has
been considerable amount of research on how cooperative transmission can improve the
performance of the network by focusing on the physical layer issues. During the past few
years, the researchers have started to take into consideration cooperative transmission in
routing and there has been a growing interest in designing and evaluating cooperative
routing protocols. Most of the existing cooperative routing algorithms are designed to
reduce the energy consumption; however, packet collision minimization using cooperative
routing has not been addressed yet. This dissertation presents an optimization framework
to minimize collision probability using cooperative routing in wireless sensor networks.
More specifically, we develop a mathematical model and formulate the problem as a
large-scale Mixed Integer Non-Linear Programming problem. We also propose a solution
based on the branch and bound algorithm augmented with reducing the search space
(branch and bound space reduction). The proposed strategy builds up the optimal routes
from each source to the sink node by providing the best set of hops in each route, the best
set of relays, and the optimal power allocation for the cooperative transmission links. To
reduce the computational complexity, we propose two near optimal cooperative routing
algorithms. In the first near optimal algorithm, we solve the problem by decoupling the
optimal power allocation scheme from optimal route selection. Therefore, the problem is formulated by an Integer Non-Linear Programming, which is solved using a branch
and bound space reduced method. In the second near optimal algorithm, the cooperative
routing problem is solved by decoupling the transmission power and the relay node se-
lection from the route selection. After solving the routing problems, the power allocation
is applied in the selected route. Simulation results show the algorithms can significantly
reduce the collision probability compared with existing cooperative routing schemes
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