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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Implementation of a Delay-Tolerant RoutingProtocol in the Network Simulator NS-3

Herbertsson, Fredrik January 2010 (has links)
Small mobile devices with networking capabilities are becoming more and more readily available and used. These devices can be used to form mobile ad hoc networks to communicate, where no infrastructure for network communication exist or where it has been destroyed or is overloaded e.g. in a natural disaster such as a hurricane. Such networks are almost never fully connected, and are part of the category of delay/disruption-tolerant networks (DTN) and suffer from limited resources e.g. bandwidth, storage and limited energy supply. The Opportunistic DTN Routing With Window-aware Adaptive Replication (ORWAR) is a delaytolerant protocol intended to be used in disaster relief efforts or emergency operations were a DTN could be a fast way to establish communication. In these kinds of scenarios high success rate together with efficient usage of the networks resources are critical to the success of such operations. ORWAR has been implemented and simulated on a high-level simulator, with promising results. To make a better assessment about what ORWARs performance would be in a real world network, more realistic and detailed simulations are needed. This Master's Thesis describes the design, implementation and evaluation of ORWAR in the network simulator ns-3, which simulates networks down to physical layer. The contributions of this thesis is a extension to ns-3 giving it an framework with support for the bundle protocol and delay-tolerant routing protocols and an evaluation of the ORWAR performance using more detailed simulations. The simulations represent a city scenario in down-town Helsinki city, Finland, were pedestrians, cars and trams form a network to communicate. The simulations with a higher level of detail has added to insight about the protocol. The obtained results showed that the high-level simulation may be overly optimistic and hides implementation details. On the other hand, some assumptions were found to be too pessimistic. For example we have shown that ORWAR actually performs better than the high level simulations, with regard to partial transmissions and that the high-level simulations have rather optimistic assumptions regarding the latency.
2

ORWAR: a delay-tolerant protocol implemented on the Android platform

Anzaldi, Davide January 2010 (has links)
The Aim of this thesis is to implement the "Opportunistic DTN Routing with Window-aware Adaptive Replication" (ORWAR) protocol on the Android platform.Delay-Tolerant Networks (DTNs) are particular mobile ad-hoc network (MANET) architectures that try to solve the issues related to the lack of point to point connectivity between the nodes of the network or between its sub-networks (partitions). The general approach is based on techniques of store-carry-forward of the messages whereby delivery can be achieved even in partitioned networks, though with mobility-dependent delays. DTNs can be considered as a means of communication for scenarios where infrastructure-based networks cannot be deployed or get dysfunctional for some reasons, such as in the case of a natural disaster or highly overloaded infrastructure. ORWAR is a DTN protocol that tries to exploit knowledge about the context of mobile nodes (speed, direction of movement and radio range) to estimate the size of a contact window in order to avoid the energy waste deriving from partial transmissions. This report presents the design and the implementation of the protocol on the Android platform. It then describes some functional tests together with an analysis of the energy consumption and the performance reachable on our test device Android Development Phone 1.

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