The purpose of this project is to utilize the Network Simulator NS2 (http://www.isi.edusnams/) to study the performance of CSMA/CD and 802.11 (CSMA/CA) protocols.

Description:

We will study CSMA/CD and 802.11 (CSMA/CA) protocols in the IEEE MAC Sub-Layer. The family of CSMA protocols usually demonstrate the following performance, as illustrated in Figure 1. With the increase of the number of contenders, the channel utilization first increases; 2. With the further increase of the number of contenders, the channel utilization the decreases.

The goal of this is to design experiments and observe this behavior.

Some terminology:

Data rate: an application achieves by measuring the amount of data transferred per unit time

Throughput: The observed rate at which data is sent through a channel.

You will need to write/modify NS2 scripts to evaluate the performance of CSMA/CD and 802.11 protocols. Specifically, you need to write/develop NS2 scripts to:

Simulate a wired LAN, to study CSMA/CD protocols;

Simulate a simple wireless LAN (Ad Hoc mode), to study 802.11 protocols.

After you finish the NS2 scripts, please run the script using the provided Virtual Machine and obtain the trace. Please analyze the trace to obtain the protocol performance.

You may use the following parameters in the simulation:

Number of nodes: 60 (n0, n1, n59)

Size of each frame: 1,000 B

Traffic: CBR (Constant Bit Rate) traffic over UDP

Running time: 100second

For other parameters (such as bandwidth, packet rate, etc.), you may search existing NS2 script and use commonly adopted values.

Please gradually increase the number of traffic pairs (to increase the number of contenders) and analyze how many data packets are dropped. You may obtain the trace file. Please write a script to analyze this trace and obtain its performance.