Wireless Network Simulation Using OPNET IT Guru Academic Edition. Part1.

1. Introduction:

1.1. What is an OPNET IT Guru:
OPNET IT Guru Academic Edition provides a virtual environment for modeling, analyzing, and predicting the performance of IT infrastructures, including applications, servers, and networking technologies. Based on OPNET's award-winning IT Guru product, Academic Edition is designed to complement specific lab exercises that teach fundamental networking concepts. The commercial version of IT Guru has broader capabilities designed for the enterprise IT environment, documentation, and professional support. OPNET software is used by thousands of commercial and government organizations worldwide, and by over 500 universities.

1.2. OPNET IT Guru wireless capabilities:
As for the OPNET Modeler designed by OPNET Technologies is the first program in the area of telecommunications networks in general, not only at the level of computer networks only. Program has great potential in many areas and is the most widely used of all universities in the world for the purposes of scientific research. As we previously stated in the free software, free version available for purposes of scientific research but is limited when compared with the commercial version.

Especially for wireless computer networks, the OPNET IT Guru Academic Edition (free version), the maximum possible to work on wireless networks is the IEEE 802.11b standard only! This version does not support the use of networks of free WiMax. Also, there are limitations in many of the options and possibilities in the free version when compared with the commercial version, including the time of simulation.

The free version and it is known as OPNET IT Guru is a great competitor to the ns-2 which is designed to work on the systems of Linux.

1.3. Purposes of the simulation of computer networks:
Two basic goals of the use of simulation programs are:

The First: scientific research, for example, the study of global IEEE Standards for wireless computer networks and ways of development and everything related to

The Second: for commercial purposes, as mentioned earlier, that if we want changes to be made to our real networks, changes are expensive, and simple mistakes that could lead to high costs, so it is possible to study the implementation of the network even before it is implemented on the ground.

1.4. Introduction to Network Simulation:
Network simulators attempt to model real world networks. The idea being that if a system can be modeled, then features of the model can be changed and the results analyzed. As the process of model modification is relatively cheap then a wide variety of scenarios can be analyzed at low cost relative to making changes to a real network.

Note: Network simulators are not perfect. They will not perfectly model your network. They will, however, be close enough so as to give you a meaningful insight into how your network is working, and how changes will effect its operation. The following figure shows the simulation cycle of any type of computer networks, this is known as the four stages of The Modeling Cycle.

In the first phase, we are modeling the network, and the process here involves the addition of computers, wiring, servers, etc. ... If we are talking about a wireless WLAN network may choose at this stage, the type of global standard IEEE 802.11b, IEEE 802.11a, IEEE 802.11g and choose the type of Modulation Method, etc…

In the second phase, we will choose the statistics. Statistics collected on the performance of the network as mentioned earlier.

In the third phase, we the simulation set up Simulate time that we want to emulate the network by. Simulation time means that, for example, if the simulation program was run on the basis of one day, all the results we get are the modeling of the network for one day on the ground, the operation of the network on the ground for a one-day operation may be offset by the simulation program for five minutes! Imagine the difference.
Fourth and final stage, is the view the simulation results and we will do our part to analyze them.