YEDITEPE UNIVERSITY
ICS 471 DATA COMMUNICATION AND COMPUTER NETWORKS
SPRING 2002
ASSIGNMENT II
(Simulation of a Real Network- Designing the Topology)
In this assignment you will try to make use of a network simulator to see how real networks are simulated and what type of enhancements can be made by using the feedback gained from the simulator.
For the purpose, you will use the QualNet, which is indeed a full-blown network simulator, especially concentrating on the wireless components and protocols. However, you will simply use wired network equipment and tools for your simulator, taking advantage of the GUI provided by QualNet. QualNet is developed by Scalable Network Technologies Inc., and brief product information and forums are available on their web site. ( QualNet is a commercial tool, and you will be provided with this tool using a trial license. You will find most of the G.P. Windows Laboratory PCs are installed with QualNet. Also head to the student assistants office to lend the CD for your home installation.
This assignment will be in two documents, one of which (you are now reading) will be explaining the topology and traffic flow you are to build using the designer of the simulator. The other document will be specifying what you will measure and which parameters you will play with.
The topology will be representing a simple campus with three faculties and a computer center. Each faculty has three Ethernet switches with 15 users connected to each switch. These switches are then connected to the Ethernet switch of the computer center. There are two possible ways to connect faculty switches to computer center switch. One is to connect each faculty switch to one port of the computer center switch. The other is to connect faculty switches to each other and connect only one switch from each faculty to computer center switch. The characteristics of these connections (capacity, delay etc.) will be a parameter of your tests. The computer center has also 15 users and a wide area connection (relatively low capacity) to Internet. To simplify the matters, Internet here is composed of three main servers on a subnet, namely web, ftp and cbr. Internet connection is a low capacity link to this subnet only.
The network you are trying to simulate will be an IP network and routing between Ethernet switches are IP routing. You will have again two options to select an IP routing scheme, namely Bellman-Ford, and OSPF. To simulate the traffic on this network, you will set up application links between users. They will be running ftp transactions among themselves (simulating file sharing) and getting Internet service from the three servers. To come up with a realistic simulation, think application logic carefully. For example, two users on the same switch (meaning they are physically co-located probably) are likely to have network activity much higher than two distinct users on two different faculties. Also while you set application timings, think that there are peak hours on network traffic, e.g. people usually will be trying to reach e-mail service at the beginning of the morning. Try to set up applications involving at least half of your users.
Inspect the simulator to learn its features. The product tour of the simulator will be a great help for a guided tour. Prepare your simulation to be at least 10 minutes. Span this 10 minutes with applications. Run and test your simulation. Then using provided features, try to measure some parameters, such as throughput, queue occupation etc.
After setting and running your simulation correctly, use the other document to set and play your test cases and prepare your graphs, charts.
Write a brief report, showing your work, choices, assumptions and graphs. The only way of submitting this assignment is by demonstrating it personally on the below date. Do not e-mail your report/code to submit it. You will be presenting your work together with the final demo of your term project.
Mesut Ali Ergin