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 delay tolerant 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.
Source: Linköping University
Author: Herbertsson, Fredrik