OPNET Technologies
7255 Woodmont Avenue
Bethesda, MD 20814
Tel: 240-497-3000
Fax: 240-497-3001
E-mail: university@opnet.com
Web: www.opnet.com

OPNET is a registered
trademark of OPNET Technologies
© 2003 OPNET Technologies

University: San Diego State University
Professor: Dr. Marko Vuskovic
Department: Computer Science

 

We are using OPNET for laboratory work/class instruction and for research.

There are two courses on senior undergraduate and graduate level, which utilize OPNET in demonstration of concepts discussed in class and in lab projects/programming assignments:

Since the usage of OPNET in teaching in Department of Computer Science has started recently, the related materials will be posted here as they are created during the Fall 2003 and Spring 2004 semesters.

There are so far two research topics that are explored by two MS candidates. The abstracts are given below.

Investigating Leaky Bucket policing Mechanisms in ATM Networks

Ahmad Salman (M.S. Thesis)

The research focuses on Investigating the Leaky Bucket Policing algorithms using Opnet Simulator. The leaky bucket is an algorithm used for conformance checking of cell flows against a set of traffic paramaters. The basic idea behind this approach is that each cell arrival creates a "cup" of fluid flow "poured" into one or more buckets for conformance checking. The cell Loss Priority (CLP) bit in ATM cell header determines which bucket(s) the cell arrival fluid pours into. The size of the bucket imposes an upper bound on burst length and determines the number of cells back to back controlling the burst length. Researchers have proposed different kind of Leaky bucket mechanisms. In the simplest version the arriving cell is dropped if it arrives at a time when the Leaky Bucket is full. Advanced leaky Bucket designs require that instead of dropping cells when leaky bucket is full, they be placed in a user buffer.Other schemes are similar except they allow nonconforming cells to enter the network and let the congested switches discard them The choice of best compromise between rate enforcement and prompt reaction has to be determined according to individual application. If both properties are required a dual leaky bucket can be used since one leaky bucket is not sufficient to control both the peak rate and the mean rate of traffic at the same time. The first leaky bucket should control the Peak rate (interarrival rate) whereas the second leaky bucket should control mean rate. The approach in this research is to exploit the tradeoff between high reaction time and high sensitivity in detection of violating cells. To ensure a proper balance between these two parameters , a triple leaky bucket scheme is proposed here. It uses one leaky bucket in series with two leaky buckets connected in parallel. The first leaky bucket in series controls the peak rate. The two parallel LB's control Leaky rate larger than mean rate and near mean rate respectively.

Analysis and Simulation of ATM-Based Industrial Networks

Irfan Siddiqui (MS Thesis)

(Abstract to be posted soon)