ABSTRACT:
The wireless communication revolution bought drastic changes to data networking,
communication. Before wireless networks Ethernet cable was used to connect computer to a
network. In this project we create four networks and analyse communication between the
networks. Wireless networks are used all around of us. With the advantage of cellular phones in
the last two decades this field has been growing exponentially.
To design this networks and sub networks we use Qualnet software. This increases
reliability and reduces the cost of the system. By using Qualnet software we are able to simulate
the system to reduce and eliminate this interference as downside of wireless networks is that it
may interfere with other wireless systems and this might cause loss of data. In this project, we are
simulating two scenarios followed by some discussion and their results.
INTRODUCTION:
First we have to create four wireless sub networks with each five nodes each. All the nodes
located in the each sub network should able to hear neighbor or each transmission as they were
connected to a Hop. Routers are used to communicate two networks. Three routers are placed in
between the sub networks. Every node is assigned with an IP address. So it is possible to have both
connectionless and connection oriented services through the networks.
In this project we mainly discuss about two scenarios in which one is mentioned above the
other is creating multiple UDP connections and comparing the results without fading and with
fading effect.
SCENARIO A:
In this scenario we have to generate two connections with the network, one UDP and the
other is TCP, and have to choose the source and destination nodes for each connection in different
sub networks.
Wireless sub network
IP Address of the sub Total
network
nodes
Sub network 1
190.0.1.0
5
Sub network 2
190.0.2.0
5
Sub network 3
190.0.3.0
5
Sub network 4
190.0.4.0
5
Table1: sub networks and their IP address
number
of Nodes assigned to sub
network
1,2,3,4,5
6,7,8,9,10
11,12,13,14,15
16,17,18,19,20
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Router node number
21
23
22
Table2: Routers and their interfaces
Sub network
Sub network A and B
Sub network B and C
Sub network C and D
Figure: interconnection among networks, routers and hops.
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So with the help of the above designed configuration, we establish two types of connections
in different networks. The following are the connections.
UDP
----
Source node: 04
----
Destination node: 11
TCP
----
Source node: 09
----
Destination node: 16
Properties of UDP connection:
Parameters selected for the UDP connection
Property
Details
Start time distribution
Exponential
Mean start time
1
Duration distribution
Deterministic
Mean duration
500
Packet size distribution
Exponential
Packet size in bytes
100
Packet interval distribution
Exponential
Mean packet interval
1.0
Packet generation probability
1
Table3: Configuration of UDP
Properties of TCP connection:
Parameters selected for TCP connection.
Property
Details
No. of data items
500
Start time
1 second
Table4: configuration of TCP connection
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Figure: communication with in the network and data transfer in TCP and UDP
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Figures: Traffic generation client and server Bar charts--UDP
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From the above bar charts it is easy that the data units sent by the source in the UDP
connection protocol is 550units and received data units at the destination node is 530units as well
in which there is no loss of data during the communication process. So scenario we configured and
efficiency of the designed wireless system is good as there is no loss during the data transmission.
Figures: File Transfer Protocol server and client Bar charts—TCP
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Figures: UDP—Packets from and to Application layer
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Figures: TCP—Data packets sent, received and retransmitted
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Figures of MAC layer: RTS packet sent, CTS packet sent, ACK packet sent
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Figures: MAC layer: Packet drops due to retransmission, Unicast packet sent and received
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From the above graph of TCP communication protocol it can be observed that total number
of bytes generated are not equal to total bytes received at the destination, so there is a loss of bytes.
MAC Layer
Node 4
Node 9
Node 11
Node 16
RTS packets sent
540
100
0
50
CTS packets sent
0
50
535
100
ACK packets sent
0
50
540
100
0
0
0
0
540
100
0
50
0
50
535
100
Packets drop due
retransmission limit
to
Unicast packet sent to
channel
Unicast packet received
Table5: Data transmission and receiving of packets in MAC layer
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SCENARIO B:
In this scenario B we arrange multiple UDP connections in the network with source and destination
nodes in different sub networks, assuming time interval between packet generations are
exponential, packet lengths also exponential and keeping average value of the packet lengths
constant during the simulation as each connection should generate at least 500 packets. In this
scenario we vary the intervals for each node and every simulation run. The results of variations in
time interval results in following graphs. This scenario is about comparison of with fading and
without fading effect.
Figures: comparison of with and without fading effect with varied intervals.
Server
Client
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Average End to End
CONCLUSION:
From the above simulation results, we conclude that the best performance can be obtained using
small packet intervals at high transmission rate, whenever the real- time application use UDP as a
transport protocol.
In case of TCP protocol as the packet interval, increased client throughput and increase the value
of server throughput because as the time interval between the generation of packets increase the
traffic load of node decrease thus decreasing the congestion.
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