Nt1310 Unit 1 Lab Report

Introduction

This is a report of discussion about Lab 1: Ethernet, which is using a software called as Riverbed Modeler Academic Edition (Edition 17.5). The topic is ‘A Direct Link Network with Media Access Control’.

Objective

The objective of this Lab 1 is to demonstrate the operation of the Ethernet network. The simulation in this lab will help examine the performance of the Ethernet network under different scenarios.

Lab Overview

Carrier Sense Multiple Access/Collision Detect (CSMA/CD) is the protocol for carrier transmission access in Ethernet networks. On Ethernet, any device can try to send a frame at any time. Each device senses whether the line is idle and therefore available to be used. If it is, the device begins to transmit

Number of Collision for Coax_0025 and Coax_Q3

In figure 5 above, it shows that the Ethernet performance can be affected by the number of nodes. For this question, the number of nodes has been reduced to 15 nodes. Originally, it was 30 nodes. The graph shows the performance of the Coax_0025 which has 30 nodes and Coax_Q3 which has only 15 nodes. When comparing these two stations, it indicates that the number of collisions is increases when the number of nodes in the network increases. So, when the number of nodes decreases, the number of collisions decreases too.

Question 4

In the simulation a packet size of 1024 bytes is used (Note: Each Ethernet packet can contain up to 1500 bytes of data). To study the effect of the packet size on the throughput of the created Ethernet network, create a duplicate of the Coax_0025 scenario. Name the new scenario Coax_Q4. In the new scenario use a packet size of 512 bytes (for all nodes). For both Coax_0025 and Coax_Q4 scenarios, choose the following global statistics:

Global Statistics -> Traffic Sink -> Traffic Received (bits/sec). Rerun the simulation of Coax_0025 and Coax_Q4 scenarios. Create a graph that compares the throughput as packets/sec and another graph that compares the throughput as bits/sec in Coax_0025 and Coax_Q4 scenarios. Explain the graphs and comment on the

Traffic Received in packets/sec

It is clear that packet size can give effects to the throughput of the Ethernet network. The graphs above (figure 6 and figure 7) indicate that the traffic received for Coax_Q4 which is 512 byte packet is bigger than Coax_0025 which is 1024 byte packets. This is because of the number of packet. When there are more packets to be sent in the network, the time efficiently will become worse. The lesser the packets sent, it can drop down the collision count. Hence, faster speed.

Conclusion

This assignment has taught me on few important things about networking. I gained some knowledge by demonstrating the different networks and protocols. I can say this software is a very useful tool for learning principles and procedures on network simulation. I have also learned that step-by-steps are very essential in practical lab. Do not skip any steps intentionally. This is because due to my experience in doing this lab, skip any steps will show different or wrong results.

There are some difficulties that I have encountered during doing this Lab 1. First problem was regarding the graph. My graph was different with the graph shown in the question. I found out there was some mistake in Coax_0025, where the exponential time supposed to be 0.025, instead I wrongly typed 0.0025. Hence, different graph has shown. After I altered the exponential time, the graph is the same as the graph shown in the