4,511 research outputs found
Managing Congestion Control in Mobile AD-HOC Network Using Mobile Agents
In mobile adhoc networks, congestion occurs with limited resources. The
standard TCP congestion control mechanism is not able to handle the special
properties of a shared wireless channel. TCP congestion control works very well
on the Internet. But mobile adhoc networks exhibit some unique properties that
greatly affect the design of appropriate protocols and protocol stacks in
general, and of congestion control mechanism in particular. As it turned out,
the vastly differing environment in a mobile adhoc network is highly
problematic for standard TCP. Many approaches have been proposed to overcome
these difficulties. Mobile agent based congestion control Technique is proposed
to avoid congestion in adhoc network. When mobile agent travels through the
network, it can select a less-loaded neighbor node as its next hop and update
the routing table according to the node congestion status. With the aid of
mobile agents, the nodes can get the dynamic network topology in time. In this
paper, a mobile agent based congestion control mechanism is presented.Comment: 9 Pages. IJCEA, 2014. arXiv admin note: substantial text overlap with
arXiv:0907.5441 by other authors without attributio
Architectural Framework for Large-Scale Multicast in Mobile Ad Hoc Networks
Emerging ad hoc networks are infrastructure-less networks consisting of
wireless devices with various power constraints, capabilities and mobility
characteristics. An essential capability in future ad hoc networks is the
ability to provide scalable multicast services. This paper presents a novel
adaptive architecture to support multicast services in large-scale wide-area ad
hoc networks. Existing works on multicast in ad hoc networks address only small
size networks. Our main design goals are scalability, robustness and
efficiency. We propose a self-configuring hierarchy extending zone-based
routing with the notion of contacts based on the small world graphs phenomenon
and new metrics of stability and mobility. We introduce a new geographic-based
multicast address allocation scheme coupled with adaptive anycast based on
group popularity. Our scheme is the first of its kind and promises efficient
and robust operation in the common case. Also, based on the new concept of
rendezvous regions, we provide a bootstrap mechanism for the multicast service;
a challenge generally ignored in previous work.Comment: 10 pages, 4 figure
Improving AODV Performance using Dynamic Density Driven Route Request Forwarding
Ad-hoc routing protocols use a number of algorithms for route discovery. Some
use flooding in which a route request packet (RREQ) is broadcasted from a
source node to other nodes in the network. This often leads to unnecessary
retransmissions, causing congestion and packet collisions in the network, a
phenomenon called a broadcast storm. This paper presents a RREQ message
forwarding scheme for AODV that reduces routing overheads. This has been called
AODV_EXT. Its performance is compared to that of AODV, DSDV, DSR and OLSR
protocols. Simulation results show that AODV_EXT achieves 3% energy efficiency,
19.5% improvement in data throughput and 69.5% reduction in the number of
dropped packets for a network of 50 nodes. Greater efficiency is achieved in
high density network and marginal improvement in networks with a small number
of nodes.Comment: 11 pages, 2 tables, 4 figure
Hybrid Scenario Based Performance Analysis of DSDV and DSR
The area of mobile ad hoc networking has received considerable attention of
the research community in recent years. These networks have gained immense
popularity primarily due to their infrastructure-less mode of operation which
makes them a suitable candidate for deployment in emergency scenarios like
relief operation, battlefield etc., where either the pre-existing
infrastructure is totally damaged or it is not possible to establish a new
infrastructure quickly. However, MANETs are constrained due to the limited
transmission range of the mobile nodes which reduces the total coverage area.
Sometimes the infrastructure-less ad hoc network may be combined with a fixed
network to form a hybrid network which can cover a wider area with the
advantage of having less fixed infrastructure. In such a combined network, for
transferring data, we need base stations which act as gateways between the
wired and wireless domains. Due to the hybrid nature of these networks, routing
is considered a challenging task. Several routing protocols have been proposed
and tested under various traffic conditions. However, the simulations of such
routing protocols usually do not consider the hybrid network scenario. In this
work we have carried out a systematic performance study of the two prominent
routing protocols: Destination Sequenced Distance Vector Routing (DSDV) and
Dynamic Source Routing (DSR) protocols in the hybrid networking environment. We
have analyzed the performance differentials on the basis of three metrics -
packet delivery fraction, average end-to-end delay and normalized routing load
under varying pause time with different number of sources using NS2 based
simulation.Comment: 15 Page
Survey of Important Issues in UAV Communication Networks
Unmanned Aerial Vehicles (UAVs) have enormous potential in the public and
civil domains. These are particularly useful in applications where human lives
would otherwise be endangered. Multi-UAV systems can collaboratively complete
missions more efficiently and economically as compared to single UAV systems.
However, there are many issues to be resolved before effective use of UAVs can
be made to provide stable and reliable context-specific networks. Much of the
work carried out in the areas of Mobile Ad Hoc Networks (MANETs), and Vehicular
Ad Hoc Networks (VANETs) does not address the unique characteristics of the UAV
networks. UAV networks may vary from slow dynamic to dynamic; have intermittent
links and fluid topology. While it is believed that ad hoc mesh network would
be most suitable for UAV networks yet the architecture of multi-UAV networks
has been an understudied area. Software Defined Networking (SDN) could
facilitate flexible deployment and management of new services and help reduce
cost, increase security and availability in networks. Routing demands of UAV
networks go beyond the needs of MANETS and VANETS. Protocols are required that
would adapt to high mobility, dynamic topology, intermittent links, power
constraints and changing link quality. UAVs may fail and the network may get
partitioned making delay and disruption tolerance an important design
consideration. Limited life of the node and dynamicity of the network leads to
the requirement of seamless handovers where researchers are looking at the work
done in the areas of MANETs and VANETs, but the jury is still out. As energy
supply on UAVs is limited, protocols in various layers should contribute
towards greening of the network. This article surveys the work done towards all
of these outstanding issues, relating to this new class of networks, so as to
spur further research in these areas.Comment: arXiv admin note: substantial text overlap with arXiv:1304.3904 by
other author
Secured Approach Towards Reactive Routing Protocols Using Triple Factor in Mobile Adhoc Networks
Routing protocols are used to transmit the packets from the source to the
destination node in mobile ad hoc networks. The intruders seek chance to pierce
into the network and becomes a cause of malfunctioning in the network. These
protocols are always prone to attacks. During the phases of routing in
different types of protocols, each of the attack finds a way to degrade the
performance of the routing protocols. The reactive routing protocols DSR and
AODV have lot of similar features and so are considered in this study. In order
to transmit the packets safely, a secured approach using triple factor has been
proposed. This triple factor computes the trust by using the direct information
then verifies the reputation by collecting the information from the
neighbouring nodes called distributed factor and uses cryptographic algorithm
to ensure security. And to ensure that there are routes available to perform
the routing process, the reasons for such attacks are studied so as to
re-integrate back the nodes in to the network, once it has repented for being
malicious before. The availability of routes increases the throughputComment: arXiv admin note: text overlap with arXiv:1708.01639,
arXiv:1710.1014
Security and Privacy Issues in Wireless Mesh Networks: A Survey
This book chapter identifies various security threats in wireless mesh
network (WMN). Keeping in mind the critical requirement of security and user
privacy in WMNs, this chapter provides a comprehensive overview of various
possible attacks on different layers of the communication protocol stack for
WMNs and their corresponding defense mechanisms. First, it identifies the
security vulnerabilities in the physical, link, network, transport, application
layers. Furthermore, various possible attacks on the key management protocols,
user authentication and access control protocols, and user privacy preservation
protocols are presented. After enumerating various possible attacks, the
chapter provides a detailed discussion on various existing security mechanisms
and protocols to defend against and wherever possible prevent the possible
attacks. Comparative analyses are also presented on the security schemes with
regards to the cryptographic schemes used, key management strategies deployed,
use of any trusted third party, computation and communication overhead involved
etc. The chapter then presents a brief discussion on various trust management
approaches for WMNs since trust and reputation-based schemes are increasingly
becoming popular for enforcing security in wireless networks. A number of open
problems in security and privacy issues for WMNs are subsequently discussed
before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the
author's previous submission in arXiv submission: arXiv:1102.1226. There are
some text overlaps with the previous submissio
Mobility-Assisted on-Demand Routing Algorithm for MANETs in the Presence of Location Errors
We propose a mobility-assisted on-demand routing algorithm for mobile ad hoc
networks in the presence of location errors. Location awareness enables mobile
nodes to predict their mobility and enhances routing performance by estimating
link duration and selecting reliable routes. However, measured locations
intrinsically include errors in measurement. Such errors degrade mobility
prediction and have been ignored in previous work. To mitigate the impact of
location errors on routing, we propose an on-demand routing algorithm taking
into account location errors. To that end, we adopt the Kalman filter to
estimate accurate locations and consider route confidence in discovering
routes. Via simulations, we compare our algorithmand previous algorithms in
various environments. Our proposed mobility prediction is robust to the
location errors.Comment: Special Issues on Recent Advances in Communications and Networking,
The Scientific World Journal, 11 figure
Aeronautical Ad Hoc Networking for the Internet-Above-The-Clouds
The engineering vision of relying on the ``smart sky" for supporting air
traffic and the ``Internet above the clouds" for in-flight entertainment has
become imperative for the future aircraft industry. Aeronautical ad hoc
Networking (AANET) constitutes a compelling concept for providing broadband
communications above clouds by extending the coverage of Air-to-Ground (A2G)
networks to oceanic and remote airspace via autonomous and self-configured
wireless networking amongst commercial passenger airplanes. The AANET concept
may be viewed as a new member of the family of Mobile ad hoc Networks (MANETs)
in action above the clouds. However, AANETs have more dynamic topologies,
larger and more variable geographical network size, stricter security
requirements and more hostile transmission conditions. These specific
characteristics lead to more grave challenges in aircraft mobility modeling,
aeronautical channel modeling and interference mitigation as well as in network
scheduling and routing. This paper provides an overview of AANET solutions by
characterizing the associated scenarios, requirements and challenges.
Explicitly, the research addressing the key techniques of AANETs, such as their
mobility models, network scheduling and routing, security and interference are
reviewed. Furthermore, we also identify the remaining challenges associated
with developing AANETs and present their prospective solutions as well as open
issues. The design framework of AANETs and the key technical issues are
investigated along with some recent research results. Furthermore, a range of
performance metrics optimized in designing AANETs and a number of
representative multi-objective optimization algorithms are outlined
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