11-04-2014, 02:38 PM
STUDY OF NETWORK SIMULATOR PACKAGES STUDY OF OPNET
AIM:
To study about OPNET - Network Simulator
INTRODUCTION:
OPNET (Optimized Network Engineering Tools) is a commercial tool from MIL3 Inc. It is being developed for almost 15 years. As everyone should guess, no much technical detail are available about the internals.
USE
Network with several hundreds of nodes can be simulated, but it would take time for the computation. OPNET is used by companies like Thomson-CSF or CNET which use it to model ATM networks and validate various layers protocols, packet switched radio networks. An example of use of OPNET is George Mason University (Quality of Service IP Network Simulation).
THE PACKAGE
The software comprises several tools and is divided in several parts, OPNET Modeler and OPNET Planner, the Model Library, and the Analysis tool. Features included in this generic simulator are an event-driven scheduled simulation kernel, integrated analysis tools for interpreting and synthesizing output data, graphical specification of models and a hierarchical object-based modeling.
OPNET Modeler is intended for modeling, simulating and analyzing the performance of large communications networks, computer systems and applications. Common uses are assessing and feasibility of new designs, optimizing already developed communication systems and predicting performance.
The modeling methodology of OPNET is organized in a hierarchical structure. At the lowest level, Process models are structured as a finite state machine. State and transitions are specified graphically using state-transition diagrams whereas conditions that specify what happen within each state are programmed with a C-like language called Proto-C. Those processes and built-in modules in OPNET (source and destination modules, traffic generators, queues, ...) are then configured with menus and organized into data flow diagrams that represent nodes using the graphical Node Editor. Using a graphical Network Editor, nodes and links are selected to build up the topology of a communication network.
The Analysis Tool provides a graphical environment to view and manipulate data collected during simulation runs. Results can be analyzed for any network element.
OPNET Planner is an application that allows administrators to evaluate the performance of communications networks and distributed systems, without programming or compiling. Planner analyses behavior and performance by discrete-event simulations. Models are built using a graphical interface. The user only chooses pre-defined models (from the physical layer to the application) from the library and sets attributes. The user cannot define new models, he should contact MIL3's modeling service.
MODELER:
OPNET Modeler is intended for modeling, simulating and analysing the performance of large communications networks, computer systems and applications. Common uses are assessing and feasibility of new designs, optimizing already developed communication systems and predicting performance.
The modeling methodology of OPNET is organized in a hierarchical structure. At the lowest level, Process models are structured as a finite state machine. State and transitions are specified graphically using state-transition diagrams whereas conditions that specify what happen within each state are programmed with a C-like language called Proto-C. Those processes, and built-in modules in OPNET (source and destination modules, traffic generators, queues, ...) are then configured with menus and organized into data flow diagrams that represent nodes using the graphical Node Editor. Using a graphical Network Editor, nodes and links are selected to build up the topology of a communication network.
TERRAIN MODELING MODULE (TMM)
Building on the capabilities of OPNET's Wireless Module, the Terrain Modeling Module provides the next level of accuracy and control for wireless network design and planning. This module allows you to model environmental effects on wireless network communications anywhere.
Featuring an open-source Longley-Rice model, the Terrain Modeling Module is ready to replicate any known atmospheric or topological conditions and their combined impact on signal propagation. Create elevation maps, line-of-sight profiles, and signal-power comparisons of mobile network models. Interfaces to read DTED and USGS DEM terrain data are provided. Open and flexible, the Terrain Modeling Module is supported by the standard Radio Transceiver Pipeline, which enables easy implementation of custom propagation models
HIGH LEVEL ARCHITECTURE (HLA)
The High-Level Architecture (HLA) Module supports building and running a federation of many simulators, each modeling some aspect of a composite system. The OPNET HLA Module enables OPNET simulations to model some portion (or the entirety) of the communications aspects of the HLA federation models. The OPNET-HLA interface provides the various simulators (federates) the necessary mechanisms to share a common object representation (for persistent elements), to exchange messages (interactions), and to maintain appropriate time synchronization.
[b]RESULT:[/b]
Thus the Network Simulator-OPNET has been studied.