Report on ns2 wireless simulation

Submitted By : Dushyant Singh - 201311027 Arun Krishnan - 201311041 Page 1

LAB REPORT

SCENARIO 1

Single Hop Static Network . N nodes (N/2 pairs of source and destination) .

CBR Traffic . Compute Average Throughput as a function of N.

The scenario considered here is simulated using N nodes as input

which are located randomly in a 100x100 grid using rand() function in ns2

simulator such that the diameter of the network is one( ie each node is in

the range of every other node) . The value of N is varied from 2 to 40 and

the variation in throughput with the change in the number of nodes is

determined using this simulation. Each of the nodes in the scenario is a

static node with the following properties:

Wireless Channel is configured for transmission using Wireless Phy

and using 802.11 MAC layer Protocol.

Two Ray Ground Propagation Model is used for transmission.

Uses DSDV Routing Protocol to route data.

The network when simulated using ns2 gives the following topological

diagram. This diagram gives the image of the network before any

transmissions start.

It can be observed from the above figure that the nodes are distributed

randomly. The above image depicts the network topology for the case of 40

nodes.


The nodes are numbered 0 to N-1 and are located randomly in the

network. Now the nodes are configured to act as UDP agents and nulls as

follows:

Each of the even numbered nodes starting from node 0 (ie 0,2,4 and so

on) are configured as UDP agents to transmit data.

Each of the odd numbered nodes starting from node 1(ie 1,3,5 and so

on) are configured as Nulls to receive data.

The nodes are connected in such a way that each of the even

numbered UDP agent node is connected to the consecutive numbered

Null node(odd numbered) like node 0 to node1, node 2 to node 3,

node 4 to node 5 and so on.


To each of the UDP agent nodes a CBR Traffic source is attached. The

CBR data is sent at a random data rate maximizing at 1Mbps. A packet size of

500 bytes is used for the transmission of CBR traffic. The simulation is run for

150ms. This is the network structure depicted above. The simulation is done

for varying number of nodes starting from 2 nodes to 40 nodes and the

values of throughput is calculated for each execution instance using the

method of trailing averages. This is done using a shell script. The values so

obtained are stored in a file with the value of throughput for each instance

recorded against the number of nodes involved in the simulation. The graph

for this scenario is shown below:


SCENARIO 2

Multi hop static network of N nodes . CBR Traffic . Compute Average

Throughput as a function of N.

In this scenario as in the above case N nodes are randomly located

using rand() function but a larger grid area of 500x500 is used .Also here each

node may not be in the range of every other node but the maximum number

of hops required for a node to communicate with any other node in the

network is 3 i.e the diameter of the network is 3. Here also for the

Throughput calculation the value of N is varied from 2 to 40 and each node

has almost the same properties as in the case of the first scenario except that

here the routing protocol used is not DSDV but AODV. The rest of the

simulation scenario remains the same as in the earlier case.


The variation of Average Throughput with the Number of nodes is

plotted in the graph below. As above we use trailing average to calculate the

value of average throughput in each instant of execution. Here also the

number of nodes varies from 2 to 40.

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Report on ns2 wireless simulation