Queuing Models in NS2

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M/M/1 is a system with poisson arrival time, servicing exponentially and a queue of unlimited capacity and type of FIFO Queue. This is the simplest queuing system.  NS2 supports various distributions like pareto, exponential, constant, unifrom, etc to handle the network dynamics and metrics. So it is very easy to test the given network link to monitor a given queue using any of these queuing models. The listing 3 and 4 are monitoring the link when DropTail queue is used with a capacity of finite and infinite. Listing 13.3 uses infinite capacity and Listing 13.4 uses Finite capacity The output screen shot is shown below the scripts for further understanding
Listing 3 – M/M/1 Queuing Model #new Simulator creation set ns [new Simulator] #trace file creation for capturing the UDP data set tf [open out.tr w] $ns trace-all $tf
#setting the exponential distribution param set lambda 30.0 set mu     33.0
#creation of nodes set n1 [$ns node] set n2 [$ns node] #The queue limit is 1Lakh as the capacity is infin…

Adding a malicious node in NS2 in AODV Protocol

Adding a malicious node is ns2 using aodv protocol. The node which is declared as malicious will simply drop the router packet (DROP_RTR_ROUTE_LOOP).

Two files have to be modified.
1. aodv.h
2. aodv.cc

aodv.h file changes
Declare a boolean variable malicious as shown below in the protected scope in the class AODV

bool malicious;

aodv.cc file changes
1. Initialize the malicious varible with a value "false". Declare it inside the constructor as shown below
AODV::AODV(nsaddr_t id):Agent(PT_AODV)...
{
.......
malicious = false;
}

2. Add the following statement to the aodv.cc file in the "if(argc==2)" statment.

if(strcmp(argv[1], "malicious") == 0) {
    malicious = true;
   return TCL_OK;
}

3. Implement the behavior of the malicious node by setting the following code in the rt_resolve(Packet *p) function. The malicious node will simply drop the packet as indicated below.

if(malicious==true)
{
drop(p,DROP_RTR_ROUTE_LOOP);
}

Once done, recompile ns2 as given below
Open Terminal -> Go to ~ns-2.35/ directory and type the command make to compile
$] cd /home/pradeep/ns-allinone-2.35/ns-2.35/
$] make

Once the compilation is done, Check the malicious behavior using the Tcl Script by setting any one node as malicious node. The command to set the malicious node is
$ns at 0.0 "[$n2 set ragent_] malicious"
The variable referred for node2 is n2 (set n2 [$ns node])

Result Analysis of Malicious Node behavior
The results of the above algorithm is analysed using tracegraph. For a given network, the malicious behavior is set.
You can download the entire files here.
1. Copy the aodv.h and aodv.cc file in the ~ns-2.35/aodv/ directory
2. Download the Tcl files for malicious and non malicious
See this post: http://www.nsnam.com/2013/10/tracegraph-installation-in-ubuntu-1310.html
Here is the screenshot shown from the tracegraph
non malicious
Non Malicious simulation

malicious
Malicious behavior
Here is the text info for the above graph:
Non Malicious
Number of generated packets: 8493
Number of sent packets: 8493
Number of forwarded packets: 0
Number of received packets: 8401
Number of dropped packets: 4
Number of lost packets: 0
Number of sent bytes: 461918
Number of forwarded bytes: 0
Number of received bytes: 2435044
Number of dropped bytes: 164
Minimal packet size: 28
Maximal packet size: 1040

Average packet size: 171.4787

Malicious
Simulation length in seconds: 21.052766
Number of nodes: 2
Number of sending nodes: 2
Number of receiving nodes: 2
Number of generated packets: 67
Number of sent packets: 54
Number of forwarded packets: 0
Number of dropped packets: 16
Number of lost packets: 0
Minimal packet size: 0
Maximal packet size: 1098
Average packet size: 125.76
Number of sent bytes: 8102
Number of forwarded bytes: 0
Number of dropped bytes: 480
Packets dropping nodes: 1

It is clear from the results that malicious is simply dropping the packet, though it generates packet and are not sent.
This post is a reproduction from www.elmurod.net with added result analysis

T S Pradeep Kumar

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