PART A
Simulation Exercises
Aim: To observe the effect of congestion by setting the parameters like, varying the queue size and page link bandwidth.
1. Simulate a three-node point-to-point network with a duplex page link between them. Set the queue size and vary the bandwidth and find the number of packets dropped.
Topology:-
Commands Used at Sender node and Receiver Node:
Sender:-
stcp –p 2000 –l 1024 1.0.1.2
Receiver:-
rtcp –p 2000 –l 1024
Results:
Case 1: set bandwidth to 10 Mbps and Queue size as 50
Output Throughput N1-P1= 1190
Input Throughput N3-P1=1190
Collision and Drop = 0
Case 2: set bandwidth to 9 Mbps on destination page link and Queue size as 50
Output Throughput N1-P1= 1190
Input Throughput N3-P1=1190
Collision and Drop = 1190
AIM: To compare the throughputs of TCP and UDP protocol and ensure that TCP provides reliable service.
2. Simulate a four-node point-to-point network and connect the page link as follows: Apply a TCP agent between n0 to n3 and apply a UDP agent between n1 and n3. Apply relevant applications over TCP and UDP agents changing the parameters and determine the number of packets sent by two agents.
Topology:-
Commands Used at Sender node and Receiver Node:
Sender:-
stcp –p 3000 –l 1024 1.0.1.3
stg –u 1024 1.0.1.3
Receiver:-
rtcp –p 3000 –l 1024
rtg –u 3000
Results:
Case 1: TCP Throughput
Set bandwidth to 100 Mbps and Queue size as 50 on both TCP and UDP links
Output Throughput N1-P1= 348-1100
Input Throughput N2-P2=320-1100
Case 2: UDP Throughput
Set bandwidth to 10 Mbps and Queue size as 50
Output Throughput N1-P1= 1148-1180
Input Throughput N2-P3=1157-1
AIM: To analyze the throughputs of Application layer protocols FTP and TELNET.

3. Simulate the different types of Internet traffic such as FTP, TELNET over a network and analyze the throughput.
Topology:-
Commands Used at Sender node and Receiver Node:
Sender:-

For FTP
stcp –p 21 –l 1024 1.0.1.3
For Telnet
stcp –p 23 –l 1024 1.0.1.3
Receiver:-
For FTP
rtcp –p 21 –l 1024
For Telnet
rtcp –p 23 –l 1024
Results:
Case 1: TCP Throughput
Set bandwidth to 10 Mbps and Queue size as 50 on both FTP and TELNET links
Output Throughput N1-P1= 680-1097
Input Throughput N3-P3=680-1097
Case 2: UDP Throughput
Set bandwidth to 10 Mbps and Queue size as 50
Output Throughput N2-P2= 495-1095
InputThroughputN3-P3=495-1095
AIM: To observe the effect of congestion while transmitting Ping messages over a network.
4. Simulate the transmission of ping messages over a network topology consisting of 6 nodes and find the number of packets dropped due to congestion.
Topology:-
Commands Used at Sender node and Receiver Node:
Sender:-
stcp –p 2000 –l 1024 1.0.1.4
Receiver:-
rtcp –p 2000 –l 1024
Command Console:-
Goto tools-> simulation time and change Simulation time to 100. During run mode, double click host 2 and then click command console. And execute the following command.
ping 1.0.1.4
Results:
While pinging with the same bandwidth on either side of the link, the Time field of the ping message is observed, and it takes much time to reach destination when the bandwidth of the destination page link is reduced.
AIM: To compare the throughput of the Ethernet by varying the Data rate and Error rate
5. Simulate an Ethernet LAN using N nodes (6-10), change error rate and data rate and compare throughput.
Topology:-
Commands Used at Sender node and Receiver Node:
Sender:-
stcp –p 2000 –l 1024 1.0.1.4
Receiver:-
rtcp –p 2000 –l 1024
Results:
Case 1: Error Rate = 0 and Data Rate = 10Mbps
Output Throughput = 654-1097
Input Throughput =654-1097
Case 2: Error Rate = 1.0 and Data Rate = 10Mbps
Output Throughput = 654-1100
Input Throughput =654-1100
Case 3: Error Rate = 1.0 and Data Rate = 100Mbps
Output Throughput = 1504-9765
Input Throughput =1504-9765