ISSUES IN AD-HOC NETWORKS full report
#1

[attachment=12217]
Presented By:
ISSUES IN AD-HOC NETWORKS
Pavankumar d Mtech , Vinaykumar Tatti
Dept of Digital Communication Networking
U.B.D.T.C.E & SJMIT Karnataka India



ABSTRACT

An ad-hoc mobile network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on a continual basis. In order to facilitate communication within the network, a routing protocol is used to discover routes between nodes. The primary goal of such an ad-hoc network routing protocol is correct and efficient route establishment between a pair of nodes so that messages may be delivered in a timely manner. Route construction should be done with a minimum of overhead and bandwidth consumption. Ad hoc networks are formed opportunistically as mobile devices come within wireless communication range of each other. Since individual devices are typically subject to severe resource limitations, it is both possible and desirable for a device to enhance its functionality by taking advantage (in a cooperative manner) of capabilities available on other devices. Ad-hoc networks are wireless mobile networks that do not rely on preexisting infrastructure. In such networks, multi-hop routing is used to achieve large degree of network


connectivity and each node in the network acts as a router for its neighbors. The range of the radio transceivers is chosen as a trade-off between full network connectivity, the reuse of the available spectrum, and power consumption.

INTRODUCTION


Since their em
ergence in the 1970s, wireless networks have become increase-ingly popular in the computing industry. This is particularly true within the past decade which has seen wireless networks being adapted to enable mobility. There are currently two variations of mobile wireless networks. The first is known as infrastructured networks, i.e., those networks with fixed and wired gateways. The bridges for these networks are known as base stations. A mobile unit within these networks connects to, and communicates with, the nearest base station that is within its communication radius. As the mobile travels out of range of one base station and into the range of another, a “hand off" occurs from the old base station to the new, and the mobile is able to continue communication seamlessly throughout the network. Typical applications of this type of network include office wireless local area networks (WLANs). The second type of mobile wireless network is the infrastructure less mobile network, commonly known as an ad-hoc network. Infrastructures less networks have no fixed routers; all nodes are capable of movement and can be connected dynamically in an arbitrary manner. Nodes of these networks function as routers, which discover and maintain routes to other nodes in the network. Example applications of ad-hoc networks are emergency search-and-rescue operations, meetings or conventions in which persons wish to quickly share information, and data acquisiti-on operations in inhospitable terrains. In recent years, there has been significant research interest in wireless ad hoc, mesh and sensor networks. An important goal is to provide communication functionality between nodes without relying on any exter-nal infrastructure. The network is typically too large to allow direct one-hop comm-unication between all node pairs. Hence nodes have to cooperate to route messages from source to destination.

Four issues in ad hoc network

1) Mobility issues

A "mobile ad hoc network" (MANET) is an autonomous system of mobile routers (and associated hosts) connected by wireless links --the union of which form an arbitrary graph. The routers are free to move randomly and organize themselves arbitrarily; thus, the network's wireless topology may change rapidly and unpredictably. Such a network may operate in a standalone fashion, or may be connected to the larger Internet. Sensor nodes consist of sensing, data processing, and communication components and typically form ad hoc networks. Due to a lack of infrastructure support, each node acts as a router, forwarding data packets for other nodes.

2) Resource Management issue

Many networked applications include provisions to adapt the behavior or functionality to best use the available computing and networking resources. These applications use one or more environment parameters to perform their adaptation. Adaptive applications are already recognized as important in the world of (managed) local and wide area networks. Because of the broader range of environment parameters that is encountered in mobile ad hoc networks, even more adaptation is expected from applications as they enter the ad hoc world.

3) Routing issue

An ad hoc network is a multihop wireless network in which mobile hosts communicate over a shared, scarce wireless channel. Ad hoc networks lack a wired backbone to maintain routes as hosts move, or turn off or on. Instead, the hosts in the ad hoc network cooperatively determine routes in a distributed manner. Thus, every host is potentially a router, and a route between two hosts may change not only because of end-host mobility but also because of intermediate router mobility. The key issues that any routing algorithm for such an environment must address are the dynamics of the topology and the overhead of route computation. Among the well known paradigms for routing, shortest path algorithms and routing on demand algorithms are at the two extremes of the spectrum. Typically, shortest path routing provides optimal routes but incurs a huge overhead in the process (in the form of periodic or event-driven updates of page link changes over the entire network). Routing on-demand, on the other hand, typically has low overhead but computes possibly non-optimal or stale routes, and requires flooding the network when no route is currently available.

4) Security issue

Advances in portable computing and wireless technology are opening up exciting possibilities for the future of mobile networking. The opportunity for applications to exploit an ever-increasing range of resources is expanding rapidly. Any application or device can advertise and provide services, turning the network into a global service repository. As portable devices become cheaper and more powerful, the number of such services is expected to grow significantly in the coming years. In part, this is because devices having limited capabilities exhibit a growing dependence on services provided by others. The ability to offer highly specialized capabilities by means of devices directly connected to the network turns such devices into service providers. In such an environment the interest in and reliance upon particular services changes over time. Expressive and dependable means are required to support service discovery. Such environments demand the ability to obtain support for the task at hand only when needed.

MOBILITY ISSUES

Characteristics of MANET

MANETs have several salient characteristics:

1) Dynamic topologies: Nodes are free to move arbitrarily; thus, the network topology which is typically multihop may change randomly and rapidly at unpredictable times, and may consist of both bidirectional and unidirectional links.

2) Bandwidth-constrained, variable capacity links: Wireless links will continue to have significantly lower capacity than their hardwired counterparts. In addition, the realized throughput of wireless communications--after accounting for the effects of multiple access, fading, noise, and interference conditions, etc. is often much less than a radio's maximum rate of transmission.


3) Energy-constrained operation: Some or all of the nodes in a MANET may rely on batteries or other exhaustible means for their energy. For these nodes, the most important system design criteria for optimization may be energy conservation.

4) Limited physical security: Mobile wireless networks are generally more prone to physical security threats than are fixed cable nets. The increased possibility of eves dropping, spoofing, and denial-of-service attacks should be carefully considered.
In addition, some envisioned networks (e.g. mobile military networks or highway networks) may be relatively large (e.g. tens or hundreds of nodes per routing area). The need for scalability is not unique to MANETS. However, in light of the preceding characteristics, the mechanisms required to achieve scalability likely are.

These characteristics create a set of underlying assumptions and performance concerns for protocol design which extend beyond those guiding the design of routing within the higher-speed, semi-static topology of the fixed Internet.

Applications


The technology of Mobile Ad hoc Networking is somewhat synonymous with Mobile Packet Radio Networking (a term coined via during early military research in the 70's and 80's), Mobile Mesh Networking (a term that appeared in an article in The Economist regarding the structure of future military networks) and Mobile, Multihop, Wireless Networking.

There is current and future need for dynamic ad hoc networking technology. The emerging field of mobile and nomadic computing, with its current emphasis on mobile IP operation, should gradually broaden and require highly-adaptive mobile networking technology to effectively manage multihop, ad hoc network clusters which can operate autonomously or, more than likely, be attached at some point(s) to the fixed Internet.

Some applications of MANET technology could include industrial and commercial applications involving cooperative mobile data exchange. In addition, mesh-based mobile networks can be operated as robust, inexpensive alternatives or enhancements to cell-based mobile network infrastructures. There are also existing and future military
networking requirements for robust, IP-compliant data services within mobile wireless communication networks [1]--many of these networks consist of highly-dynamic autonomous topology segments. Also, the developing technologies of "wearable" computing and communications may provide applications for MANET technology. When properly combined with satellite-based information delivery, MANET technology can
provide an extremely flexible method for establishing communications for fire/ safety/ rescue operations or other scenarios requiring rapidly-deployable communications with survivable, efficient dynamic networking. There are likely other applications for MANET technology which are not presently realized or envisioned by the authors. It is simply put, improved IP-based networking technology for dynamic, autonomous wireless networks.


RESOURCE MANAGEMENT ISSUE

A variety of different types of devices may serve as nodes in a Mobile Ad hoc Network (MANET). Every node must be equipped with a transmitter and receiver in order to allow wireless communication, however each may have a different set of abilities. Typically, the functionalities and resources available to the node are suited to the device's particular purpose and requirements.
Participation in a MANET places a burden on a node, in addition to its primary functions. Each node is asked to also forward packets for the rest of the network. This consumes some or all of a node's resources, including processing time, energy stores, and network bandwidth. Depending on the amount of routing demand placed on a node, the additional routing load may reduce or drain a node's available resources. A node may then be forced to restrict its own operations, or even shut down, abandoning all functionality.
A node is required to participate in the routing process in order for the network to effectively deliver its traffic. The load placed on the node is dependent on the routing protocol used in the network. In most ad hoc routing protocols, a node has little choice as to how much forwarding it must perform. If it feels it cannot perform these duties, or chooses not to, for whatever reason, it has only two choices: to break the rules of the routing protocol, or to withdraw from the network. Both solutions will have a negative impact on the network as a whole.
Some of the important issues that we are investigating include:
• Policy-based resource management
• Access control and policing
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page
Popular Searches: arbitrarily, b e cse report format for review 1 in ad hoc networks, report of multicast routing and issues in ad hoc network, security issues in mobile ad hoc networks, suggested topics for report on contemporary issues in management, project report on adolescent myths and issues, project report on contemporary issues,

[-]
Quick Reply
Message
Type your reply to this message here.

Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  Transparent electronics full report seminar surveyer 8 24,349 04-04-2018, 07:54 AM
Last Post: Kalyani Wadkar
  wireless charging through microwaves full report project report tiger 90 70,539 27-09-2016, 04:16 AM
Last Post: The icon
  Wireless Power Transmission via Solar Power Satellite full report project topics 32 50,213 30-03-2016, 03:27 PM
Last Post: dhanabhagya
  surge current protection using superconductors full report computer science technology 13 26,844 16-03-2016, 12:03 AM
Last Post: computer science crazy
  paper battery full report project report tiger 57 61,680 16-02-2016, 11:42 AM
Last Post: Guest
  IMOD-Interferometric modulator full report seminar presentation 3 11,360 18-07-2015, 10:14 AM
Last Post: [email protected]
  digital jewellery full report project report tiger 36 66,483 27-04-2015, 01:29 PM
Last Post: seminar report asees
  Implementation Issues in Spectrum Sensing for Cognitive Radios seminar surveyer 3 3,639 16-03-2015, 02:23 PM
Last Post: seminar report asees
  LOW POWER VLSI On CMOS full report project report tiger 15 22,190 09-12-2014, 06:31 PM
Last Post: seminar report asees
  eddy current brake full report project report tiger 24 33,401 14-09-2014, 08:27 AM
Last Post: Guest

Forum Jump: