This report has two scenarios - First one having 2 connections, UDP and TCP. Another scenario has 4 TCP connections having a comparison with and without fading.

1. 1
PROJECT REPORT
Simulation of a Wireless Sub Network using QualNET.
Submitted by:
Daksh Raj Chopra
ID: 40054446
Anterdeep Kaur
ID: 40043579
Submitted to:
Dr. Dongyu Qiu

2. 2
ABSTRACT
This report includes designing and simulation of a wireless network using a software named
Qualnet Simulator. This project contains four wireless sub-networks (A, B, C, and D) each
having 5 nodes. The design also includes 3 routers to forward the packets between wireless
sub-networks. In this project, forwarding of data packets is allowed by only routers. The
report includes the simulation results in the form of bar charts of various performance
measures. The whole project is divided into two scenarios - A and B. We have also taken the
effect of fading into consideration while comparing the results. By simulation, we can easily
notice the difference that due to fading, there is always some disturbance in communication
and it also results in loss of data.

3. 3
Table of Figures
Figure 1 Network for Scenario A…………………………………………………….…….……….…… 5
Figure 2 Traffic Client: Data Units Sent……………………………………….……….…...………...…6
Figure 3 Traffic Server: Data Units Received………………………………....…….…………………...7
Figure 4 Traffic Server: Average End to End Delay……………..……………….……………………...7
Figure 5 Traffic Client: Total Bytes Sent………………………………………….…………..................7
Figure 6 Traffic Client: Throughput………………………………………...…….…………….………..8
Figure 7 Traffic Server: Total Bytes Received………………………...………..………………………..8
Figure 8 Traffic Server: Throughput……………………………………………..………….…………...9
Figure 9 Packets received from application layer for UDP………………………………….....................9
Figure 10 Packets received to application layer for UDP………………………………….………….......10
Figure 11 Data Packets received-TCP……………………………………………………….........……...10
Figure 12 Data Packets Sent-TCP…………………………………………………………………....…..11
Figure 13 Data Packets retransmitted-TCP………………………………………………….…………...11
Figure 14 CTS packets sent………………………………………………......…………….……….........12
Figure 15 RTS packets sent……………………………………………………….………………….......12
Figure 16 ACK packets sent……………………………………………………………………………...13
Figure 17 Packets drop due to transmission limit…………………………………………………………13
Figure 18 Unicast sent…………………………………………………………………….……………...14
Figure 19 Unicast received………………………………………………………………….……………14
Figure 20 Scenario B………………………………………………………………………….………….16
Figure 21 Average UDP packet delay with and without fading……………………………………..........17
Figure 22 UDP client throughput with and without fading ………………….……….………...……….18
Figure 23 UDP server throughput with and without fading ………………………………..……………18

4. 4
1. Introduction
This report presents the designing and simulation of a wireless network using the Qualnet
software. There are four different wireless sub-networks with five nodes each. The sub-networks
have been connected to the neighboring sub-network i.e. A<->B<->C<->D<->A. Routers are
placed between all the sub-networks to allow packet forwarding and these are only allowed to
forward packets. Also, IEEE 802.11 is used as MAC protocol and IPv4 as the network protocol.
There are two scenarios discussed, scenario A and scenario B.
For designing and simulating wireless networks, Qualnet Simulator software is used in many
industries. QualNet provides a unique capability for accurate, efficient simulation of large-scale,
heterogeneous networks. The designers can design and simulate a virtual network which is close
to a real network. One can control different parameters and can analyze the effects of the same in
the actual network. This reduces the effective cost of the company or industries since they are not
setting up the network and then checking for the errors or flaws in the design.
In scenario A, two connections in the network are generated, one UDP (through TRAFGEN) and
the other TCP (through FTPGEN), the source and destination nodes for each connection are in
different subnetworks. In scenario B, multiple UDP connections in the network have been created
with source and destination nodes in different sub-networks.
2. SCENARIO A
In Scenario A, we have created 4 wireless subnetworks and have referred them A, B, C and D.
Each subnetwork has 5 nodes and all the nodes are randomly placed. The subnetworks connect
with each other through routers such that A connects B, B connects C, and C connects D.
In this scenario, two connections are considered TCP (between node 8 and 15) and UDP (between
node 22 and 13). Each connection generates at least 500 packets.

5. 5
Fig.1 Network for Scenario A.
Parameters for Scenario A.
a) Packet size - 512 bytes
b) Mean start time - 260 sec
c) Average UDP connection time - 500 sec
d) Average UDP time interval - 0.5 sec
e) TCP end time - 50 sec
f) Simulation Time - 260 sec
Subnetworks Node Number IP Address
A
3 190.0.1.1
10 190.0.1.2
14 190.0.1.4
17 190.0.1.5
22 190.0.1.6
A -> B 11
190.0.1.3
190.0.3.3
B
6 190.0.3.1
12 190.0.3.4

6. 6
18 190.0.3.5
21 190.0.3.6
8 190.0.3.2
B -> C 16
190.0.2.4
190.0.4.6
C
2 190.0.4.1
4 190.0.4.2
5 190.0.4.3
7 190.0.4.4
15 190.0.4.5
C ->D 23
190.0.3.7
190.0.4.7
D
1 190.0.2.1
9 190.0.2.2
13 190.0.2.3
17 190.0.1.5
19 190.0.2.5
The following are the bar charts for all the performance measures.
2.1 Application Layer
2.1.1 UDP Traffic Client - Total Data Units Sent
Fig.2 UDP Client - Total Data Units Sent

7. 7
2.1.2 UDP Traffic Server-Total Data Units Received
Fig. 3 UDP Server – Total Data Units Received
2.1.3 UDP Server-Average End To End Delay
Fig. 4 Average End to End UDP Delay.
2.1.4 TCP Client-Total Bytes Sent

8. 8
Fig.5 TCP Client –Total Bytes Sent
2.1.5 TCP Client-Throughput
Fig. 6 TCP Client – Throughput (bits/sec)
2.1.6 TCP Server- Total Bytes Received
Fig.7 TCP Server –Total Bytes Received

9. 9
2.1.7 TCP Server-Throughput
Fig. 8 TCP Server- Throughput (Bits/sec)
2.2 Transport Layer
2.2.1 UDP-Packets from Application Layer
Fig. 9 UDP – Packets from Application Layer

10. 10
2.2.2 UDP – Packets to Application Layer
Fig. 10 UDP- Packets to Application Layer
2.2.3 TCP- Data Packets Received
Fig. 11 TCP –Data Packets Received

11. 11
2.2.4 TCP – Data Packets Retransmitted
Fig. 12 TCP – Data Packets Retransmitted
2.2.5 TCP – Data Packets Sent
Fig.13 TCP – Data Packets Sent

12. 12
2.3. MAC Layer
2.3.1 CTS Packets Sent
Fig. 14 CTS Packets Sent
Node Node 8 Node 13 Node 15
CTS Packets Sent 434 650 731
2.3.2 RTS Packets Sent
Fig. 15 RTS Packets Sent
Node Node 8 Node 15 Node 22
RTS Packets Sent 787 461 678

13. 13
2.3.3 ACK Packets Sent
. Fig. 16 ACK Packets Sent
Node Node 8 Node 13 Node 15
ACK Packets Sent 400 521 517
2.3.4 Packet Drops Due to Retransmission Limit
Fig. 17 Packets drop due to Retransmission Limit
Node Node 8 Node 22
Packets drop due to
Retransmission Limit
3 2

14. 14
2.3.5 Unicasts Sent
Fig. 18 Unicasts Sent
Node Node 8 Node 15 Node 22
Unicast Sent 503 385 516
2.3.6 Unicasts Received
Fig. 19 Unicasts Received
Node Node 8 Node 13 Node 15
Unicast Received 385 516 503

15. 15
Discussion and Observations
 Application Layer
1. UDP
Traffic Client Traffic Server
Source Total Data Units
Sent
Destination Total Data Units
Received
Node 22 518 Node 13 516
From above table, it can be watched that two data units are lost, which demonstrates that
UDP does not permit flow control and error correction.
Average end to end delay
From figure 4 it is observed that the average end-to-end delay is very low (0.00439775).
Thus, UDP allows the fastest and straightforward way of transmitting data to the receiver.
There is no interference in the stream of data that can be possibly avoided. This provides the
way for an application to get as close to meet the real-time constraints as possible.
2. TCP
Traffic Client Traffic Server
Source Node 8 Destination Node 15
Total Data Units
Sent
500 Total Data Units
Received
500
Throughput 620077 Throughput 589482
From above table, it can be observed that total bytes sent and received are equal, which shows
that TCP allows flow control and error correction. Flow control determines when data needs
to be re-sent and stops the flow of data until previous packets are successfully transferred.
This works on the grounds that if a data packet is sent, a collision may happen. At the point
when this happens, the server re-asks for the packet from the client until the point that the
entire packet is finished and is indistinguishable to its unique.

16. 16
3. Scenario B
Four wireless sub-networks are connected A, B, C and D are connected to each other through
four routers. Each sub-network contains more than 5 nodes. The wireless subnetworks are
used IEEE 802.11 as MAC protocol and IPv4 as a network protocol. In Scenario B
connections are established between two random node pairs in the network. Here three
connections are configured to UDP service (TRAF GEN). We have taken Rayleigh Fading
into consideration for calculating the average packet delay and throughput with fading.
Fig 20. Scenario B
Parameters for Scenario B
a) Mean start time: Exponential and 1 sec
b) Duration: Deterministic and 30 secs
c) Packet size distribution: Exponential and 512 bytes
d) Mean packet interval: Exponential
e) Simulation time: 3000 secs

17. 17
In this scenario, we have three UDP connections between nodes of different subnets, but we have
chosen a single connection to study the distinct characteristics of fading with main respect to mean
packet interval. Three main things which we notice is Average UDP packet delay, Client
throughput, and Server throughput.
UDP Connection between node 2 and 1.
3.1 Average UDP packet delay with and without fading (sec)
Mean PacketInterval Withfading Withoutfading
0.5 0.0139069 0.00621514
1.5 0.0129848 0.00550286
2.5 0.0115828 0.00525588
3.5 0.0115503 0.00542225
4.5 0.0125669 0.00600283
Fig 21. Average UDP packet delay with and without fading
3.2 UDP Client throughput with and without fading (bits/sec)
Mean PacketInterval Withfading Withoutfading
0.5 7862.93 7862.93
1.5 2592.93 2592.93
2.5 1554.64 1554.64
3.5 1095 1095
4.5 864.308 864.308
0.0139069
0.0129848
0.0115828 0.0115503
0.0125669
0.00621514
0.00550286 0.00525588 0.00542225 0.00600283
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Delay
Mean Packet Interval
AveragePacketDelay
With fading Without fading

18. 18
Fig 22. UDP client throughput with and without fading
3.3 UDP server throughput with and without fading (bits/sec)
Mean PacketInterval Withfading Withoutfading
0.5 7145.32 6920.74
1.5 2216.32 2261.29
2.5 1217.2 1403.68
3.5 991.241 983.31
4.5 713.584 790.026
Fig 23. UDP server throughput with and without fading
7862.93
2592.93
1554.64
1095 864.308
7862.93
2592.93
1554.64
1095 864.308
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Throughput(bits/sec)
Mean Packet Interval
UDP Client Throughput
With fading Without fading
0
1000
2000
3000
4000
5000
6000
7000
8000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Throughput(bits/sec)
Mean Packet Interval
UDP Server Throughput
With fading Without fading

19. 19
The traffic load of a node decreases with increase in the time interval between packet
generations which causes an increase in packet delay. However numerous factors affect the
average packet delay; one of them is the actual queue size in the router buffer. So, the average
packet delay sometimes increases sharply and sometimes decreases sharply with increase in
packet interval. The overall average packet delay decreases with increase in packet interval
as shown in the plot. Average UDP client and server throughput decreases with increase in
mean packet interval. This is because when a packet interval is increased, packet generation
becomes less thus decreasing the throughput. But average TCP client and server throughput
increases as the mean packet interval increases. This is because as the time interval between
the generations of packets increases the traffic load of a node decrease thus decreasing the
congestion on the given link.
Conclusion
We conclude from Scenario A that several data units sent by the client is equal to the number
of units received by the server. Also, the CTS, RTS and ACK packets add up approximately.
In Scenario B, the plots for server throughput shows that the difference between the
throughput of Fading and the non-Fading environment is negligible for the smaller distance
between the nodes and this difference increases with the larger distances between the nodes.
From the results, we also conclude that UDP client and server throughput is much less than
TCP client and server throughput.