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Challenges of MANETs

A Manet environment has to overcome certain issues of limitation and inefficiency. It includes: ·          The wireless link characteristics are time-varying in nature: There are transmission impediments like fading, path loss, blockage and interference that adds to the susceptible behavior of  wireless channels. The reliability of wireless transmission is resisted by different factors. ·          Limited range of wireless transmission – The limited radio band results in reduced data rates compared to the wireless networks. Hence optimal usage of bandwidth is necessary by keeping low overhead as possible. ·          Packet losses due to errors in transmission – MANETs experience higher packet loss due to factors such as hidden terminals that results in collisions, wireless channel issues (high bit error rate (BER)), interference, and frequent breakage in p...
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Characteristics of MANETs

·      In MANET, each node act as both host and router. That is it is autonomous in behavior.  ·      Multi-hop radio relaying- When a source node and destination node for a message is out of the radio range, the MANETs are capable of multi-hop routing. ·      Distributed nature of operation for security, routing and host configuration. A centralized firewall is absent here. ·      The nodes can join or leave the network anytime, making the network topology dynamic in nature. ·      Mobile nodes are characterized with less memory, power and light weight features. ·      The reliability, efficiency, stability and capacity of wireless links are often inferior when compared with wired links. This shows the fluctuating link bandwidth of wireless links. ·      Mobile and spontaneous behavior which demands minimum human intervention to conf...
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Types of MANETs

There are different types of MANETs including:         InVANETs – Intelligent vehicular ad hoc networks make use of artificial intelligence to tackle unexpected situations like vehicle collision and accidents.           Vehicular ad hoc networks (VANETs) – Enables effective communication with another vehicle or helps to communicate with roadside equipments.           Internet Based Mobile Ad hoc Networks (iMANET) – helps to link fixed as well as mobile nodes.
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What is a MANETs

It is an infrastructure less IP based network of mobile and wireless machine nodes connected with radio. In operation, the nodes of a MANET do not have a centralized administration mechanism. It is known for its routable network properties where each node act as a “router” to forward the traffic to other specified node in the network.
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Data Dissemination Broadcast-disk Models

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Data Dissemination Broadcast-disk Models: ·          Presumed that all the n records to be broadcast are stored on a circular disk from 0° to 360° ·          A hypothetical disk revolves and the angle changes from 0°to 360° ·          The entire N bits in n records get pushed through a hypothetical reading-head over the disk. ·          The head continuously reads each bit of a record just beneath it and broadcasts it instantaneously on the wireless network ·          During next revolution each bit in the records positioned from 0° to 360° broadcast once again in the same sequence as in earlier revolution Number of adaptations and algorithms for broadcast: 1. Circular Multi-disk Model 2. Flat Disk Model 3. Multi-disk Model with repetition rate proportional to pr...
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Classification of Data-Delivery Mechanisms in mobile computing

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Data Dissemination and Broadcasting Systems: Classification of Data-Delivery Mechanisms: ·          Push-based mechanisms (publish–subscribe mode) ·          Pull-based mechanisms (on-demand mode) ·          Hybrid mechanisms (hybrid mod                        Push-based Mechanisms: ·          Server pushes data records from a set of distributed computing systems ·          Examples of distributed computing systems advertisers or generators of traffic congestion, weather reports, stock quotes, and news report A server or computing system pushing the data records from a set of distributed systems : Publish–subscribe mode • In which the data push...
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Client Server Computing with Adaptation

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Client Server Computing with Adaptation • Two adapters (adaptation software) at a mobile device • An adapter for standard data format for synchronization at the mobile-device • Another adapter for the backend database copy, which is in a different data format for the API at the mobile-device Adaptation: Software to get data in one format or data governed by one protocol and convert it to another format or to data governed by another protocol ·          Used for interchange between standard data formats and data formats for the API ·          IBM WebSphere Everyplace Access (WEA) provides adapters for synchronization objects (for example, XML format synchronization objects) and the objects of API databases (for example, for the PIM APIs)
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