Networking lab

CS9216 NETWORKING LAB(C/C++)

LIST OF EXPERIMENTS

1. Socket Programming
a. TCP Sockets

b. UDP Sockets

c. Applications using Sockets

2. Simulation of Sliding Window Protocol

3. Simulation of Routing Protocols

4. Development of applications such as DNS/ HTTP/ E – mail/ Multi -
user Chat

5. Simulation of Network Management Protocols

6. Study of Network Simulator Packages – such as opnet, ns2, etc.

HARDWARE REQUIREMENTS

Processor :Pentium IV

Hard disk :20 GB

RAM :256 MB

Monitor :VGA and high resolution monitor

SOFTWARE REQUIREMENTS

Operating system :LINUX

Language :C/C++

Ex.no:1 CLIENT-SERVER CHAT PROGRAM
Date: USING TCP

AIM

To write a C program for implementing Client-Server Chat using TCP.

ALGORITHM

SERVER
Step 1: Start the program.
Step 2: Create an unnamed socket for the server using the
parameters AF_INET as domain and the SOCK_STREAM as type.
Step 3: Name the socket using bind( ) system call with the
parameters server_sockfd and the server address(sin_addr and sin_sport).
Step 4: Create a connection queue and wait for clients using the listen( ) system call
with the number of clients request as parameters.
Step 5: Accept the connection using accept( ) system call when client requests for
connection.
Step 6: Get the message which has to be sent to the client and check that it is not
equal to ‘Bye’.
Step 7: If the message is not equal to ‘Bye’ then write the message to the client and
Goto step 6.
Step 8: If the message is ‘Bye’ then terminate the Process.
Step 9: Stop the program execution.

CLIENT
Step 2: Create an unnamed socket for client using socket( ) system.
Step 3: Call with parameters AF_INET as domain and SOCK_STREAM as type.
Step 4: Name the socket using bind( ) system call.
Step 5: Now connect the socket to server using connect( ) system call.
Step 6: Read the message from the server socket and compare it with ‘Bye’.
Step 7: If the message is not equal to ‘Bye’ then print the message to the server
output device and repeat the steps 6 & 7.
Step 8: Get the message from the client side.
Step 9: Write the message to server sockfd and goto step 4.
Step 10:If the message is equal to ‘Bye’then print good bye message and terminate
the process.
Step 11:Stop the process.

CLIENT SERVER CHAT USING TCP

SERVER
#include<stdio.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<string.h>

main()
{
int sd,sd2,nsd,clilen,sport,len;
char sendmsg[20],rcvmsg[20];
struct sockaddr_in servaddr,cliaddr;
printf("Enter the Server port");
printf("n_____________________n");
scanf("%d",&sport);
sd=socket(AF_INET,SOCK_STREAM,0);
if(sd<0)
printf("Can't Create n");
else
printf("Socket is Createdn");
servaddr.sin_family=AF_INET;
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
servaddr.sin_port=htons(sport);
sd2=bind(sd,(struct sockaddr*)&servaddr,sizeof(servaddr));
if(sd2<0)
printf(" Can't Bindn");
else
printf("n Bindedn");

listen(sd,5);
clilen=sizeof(cliaddr);
nsd=accept(sd,(struct sockaddr*)&cliaddr,&clilen);
if(nsd<0)
printf("Can't Acceptn");
else
printf("Acceptedn");
printf("nReceived Messagesn");
do
{
recv(nsd,rcvmsg,20,0);
printf("%s",rcvmsg);
fgets(sendmsg,20,stdin);
len=strlen(sendmsg);
sendmsg[len-1]='0';

send(nsd,sendmsg,20,0);
wait(20);
}
while(strcmp(sendmsg,"bye")!=0);
}

CLIENT

#include<stdio.h>
main()
{
int csd,cport,len;
char sendmsg[20],revmsg[20];
struct sockaddr_in servaddr;
printf("Enter the portn");
scanf("%d",&cport);
csd=socket(AF_INET,SOCK_STREAM,0);
if(csd<0)
printf("Can't Createn");
else
printf("Scocket is Createdn");
servaddr.sin_port=htons(cport);
if(connect(csd,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)
printf("Can't Connectn");
else
printf("Connectedn");

do
{
sendmsg[len-1]='0';
send(csd,sendmsg,20,0);
wait(20);
recv(csd,revmsg,20,0);
printf("%s",revmsg);
}
while(strcmp(revmsg,"bye")!=0);
}

OUTPUT:

Client Side

[1me16@localhost ~]$ cc tcpclient.c
[1me16@localhost ~]$. /a.out
Enter the port
6523
Socket is Created…
Connected……
Hello

Server Side

[1me16@localhost ~]$ cc tcpserver.c.c
Enter the server port…
6543
Socket is Created
Binded
Accepted
Received Messages…. Hello

RESULT
Thus the C program for chat using TCP is executed and the output is verified
successfully

Ex.no:2 CLIENT-SERVER CHAT USING UDP
Date:

AIM
To write a C program for implementing chat program using UDP.

ALGORITHM

SERVER

parameters AF_INET as domain and the SOCK_DGRAM as type.
parameters server_sockfd and the server
address(sin_addr and sin_sport).
Step 4: The server gets the message from the client.
Step 5: Prints the message.

CLIENT
Step 2: Create an unnamed socket for client using socket
Step 3: Call with parameters AF_INET as domain an
SOCK_DGRAM as type.
Step 5: The Sendto( ) system call is used to deliver the
Message to the server.

CLIENT SERVER CHAT USING UDP

SERVER

#include<stdio.h>
#include<sys/socket.h>
main()
{
struct sockaddr_in sadd,cadd;
int id,a,b,len,port;
char rbuff[100];
id=socket(PF_INET,SOCK_DGRAM,0);
if(id<0)
else
printf("Createdn");
printf("Enter the port Addressn");
printf("____________________n");
scanf("%d",&port);
sadd.sin_family=PF_INET;
sadd.sin_addr.s_addr=htonl(INADDR_ANY);
sadd.sin_port=htons(port);
b=bind(id,(struct sockaddr*)&sadd,sizeof(sadd));
if(b<0)
printf("Can't Bind");
else
printf("Bindedn");
printf("~~~~~~n");
len=sizeof(cadd);
if(recvfrom(id,rbuff,sizeof(rbuff),0,(struct sockaddr*)&cadd,&len)<0)
printf("Received Errorn");
else
printf("Server received =%sn",rbuff);
close(id);

}

CLIENT
#include<stdio.h>
main()
{
struct sockaddr_in sadd,cadd;
int id,len,n,c,s,b,port;
char str[100],serstr[100];
id=socket(PF_INET,SOCK_DGRAM,0);
if(id<0)

else
printf("Enter the IP addressn");
scanf("%s",serstr);
printf("Enter the port Addressn");
scanf("%d",&port);
cadd.sin_family=PF_INET;
cadd.sin_addr.s_addr=inet_addr(serstr);
cadd.sin_port=htons(port);
printf("Enter the Datan");
scanf("%s",str);
b=bind(id,(struct sockaddr*)&cadd,sizeof(cadd));

if(sendto(id,str,sizeof(str),0,(struct sockaddr*)&cadd,sizeof(cadd))<0)
printf("Transmit Error");
else
printf("Server Transmitted=%sn",str);
close(id);
}

OUTPUT:

Client Side

[1me16@localhost ~]$ cc udpclient.c
Socket is Created…
Enter the IP Address
172.15.170.104
Enter the port address
6543
Enter the data
Hello
Server transmitted = hello

Server Side

[1me16@localhost ~]$ cc udpserver.c
Created
………….
6543
Binded
…………….

RESULT
Thus the C program for chat using UDP is executed and the output is verified
successfully.

Ex. No. 3a PRINTING THE CLIENT ADDRESS
Date: AT THE SERVER END
AIM

To write a C program for printing the client address at the server end.

ALGORITHM

SERVER
parameters AF_INET as domain and the SOCK_STREAM as type.
parameters server_sockfd and the server address(sin_addr and sin_sport).
Step 4: Create a connection queue and wait for clients
using the listen( ) system call with the number of clients request as
parameters.
Step 5: Accept the connection using accept( ) system call when client requests for
connection.
Step 6: If the descriptor is less than zero,then the connection is not established and
the stop the process.
Step 7: Print the IP address sent by the client to the server.

CLIENT

Step 2: Create an unnamed socket for client using socket( ) system.
Step 5: Now connect the socket to server using connect( ) system call.
Step 6: If the descriptor is less than zero, then the
connection is not established.
Step 7: If there is no connection,then terminate the process.
Step 8: Else send the IP address to the server.
Step 9: Stop the process.

PRINTING THE CLIENT ADDRESS AT THE SERVER END

SERVER

#include<stdio.h>
#include<string.h>

main()
{
printf("Enter the Portn");
scanf("%d",&sport);
if(sd<0)
else
servaddr.sin_addr.s_addr=inet_addr("172.15.170.104");
if(sd2<0)
else
listen(sd,5);
if(nsd<0)
else
printf("The Client Address is %s",inet_ntoa(cliaddr.sin_addr.s_addr));

}

CLIENT
#include<stdio.h>
main()
{
int csd,cport,len;
scanf("%d",&cport);
if(csd<0)
else
servaddr.sin_addr.s_addr=inet_addr("172.15.170.104");
else

}

OUTPUT:

Client Side

[1me16@localhost ~]$ cc addressclient.c
Enter the port:
6543
Socket is Created...

Server Side

[1me16@localhost ~]$ cc addressserver.c
Enter the port:
6543
Created...
Binded……

RESULT
Thus the C program for printing the client IP Address at the server end is executed
and the output is verified successfully.

Ex.no: 3b DATE-TIME SERVER
Date:
AIM
To write a C program for implementing the simple TCP client-server where the
server acts as a Date-Time server.

ALGORITHM

SERVER
Step 1 :Start the program
Step 2 :Create an unnamed socket for the server using parameters AF_INET as
domain and SOCK_STREAM as type.
Step 3 : Declare the time variables t.
Step 4 :Get the server port number.
Step 5 :Register the host address to the system by using bind() system call in server
side.
Step 6 :Create a connection queue and wait for clients using listen() system call with
The number of clients requests as parameter.
Step 7 :Accept the connection using accept( ) system call when the client
request for connection.
Step 8 :Stop the Program execution.

CLIENT
Step 1 :Start the program.
Step 2 :Create an unnamed socket for the client using parameters AF_INET as
Step 3 :Get the client port number.
Step 4 :Now connect the socket to server using connect( ) system call.
Step 5 :The recv() system call gets the response of Date-Time request from the
server.
Step 6 :Print the date and time
Step 7 :Stop the program.

DISPLAYING TIME AT THE CLIENT END

SERVER

#include<stdio.h>
#include<string.h>
#include<time.h>
main()
{
time_t t;
printf("Enter the Port non");
scanf("%d",&sport);
time(&t);
strcpy(sendmsg,ctime(&t));
printf("%s",sendmsg);
if(sd<0)
else
if(sd2<0)
else
printf("n Binded n");

listen(sd,5);
if(nsd<0)
else

}

CLIENT
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
main()
{
int csd,cport,len;
char revmsg[100];
scanf("%d",&cport);
if(csd<0)
else
printf("Connection errorn");
printf("%sn",revmsg);

}

OUTPUT:

Client Side

[1me16@localhost ~]$ cc dateclient.c
Enter the port:
8543
Connected…

Server Side

[1me16@localhost ~]$ cc dateserver.c
Enter the port:
8543
Fri Sep 17 03:05:27 2010

RESULT
Thus the C program for printing Date and time is executed and the output is verified
successfully.

Ex.no:3c FILE TRANSFER USING TCP
Date:
AIM:
To write a C program for transferring a file using TCP.

ALGORITHM:
SERVER:

Step 1:Start the program.
Step 2:Create an unnamed socket for the server using parameters AF_INET as
Step 3:Get the server port number.
Step 4:Register the host address to the system by using bind() system call in server
side.
Step 5:Create a connection queue and wait for clients using listen() system call with
the number of clients requests as parameter.
Step 6:Create a Child process using fork( ) system call.
Step 7:If the process identification number is equal to zero accept the connection
using accept( ) system call when the client request for connection.
Step 8:If pid is not equal to zero then exit the process.
Step 9:Stop the Program execution.

CLIENT:

Step 1:Start the program.
Step 2:Create an unnamed socket for the client using parameters AF_INET as
Step 3:Get the client port number.
Step 4:Now connect the socket to server using connect( ) system call.
Step 5:Enter the file name.
Step 6:The file is transferred from client to server using send ( ) function.
Step 7:Print the contents of the file in a new file.
Step 8:Stop the program.

FILE TRANSFER PROTOCOL
USING TCP

SERVER
#include<stdio.h>
#include<string.h>

main()
{
FILE *fp;
int sd,newsd,ser,n,a,cli,pid,bd,port,clilen;
char name[100],fileread[100],fname[100],ch,file[100],rcv[100];
printf("Enter the port address: ");
scanf("%d",&port);
if(sd<0)
else

servaddr.sin_port=htons(port);
a=sizeof(servaddr);
bd=bind(sd,(struct sockaddr*)&servaddr,a);
if(bd<0)
else

listen(sd,5);
newsd=accept(sd,(struct sockaddr*)&cliaddr,&clilen);
if(newsd<0)
else

n=recv(newsd,rcv,100,0);
rcv[n]='0';
fp=fopen(rcv,"r");
if(fp==NULL)
{

send(newsd,"error",5,0);
close(newsd);
}

else
{
while(fgets(fileread,sizeof(fileread),fp))
{
if(send(newsd,fileread,sizeof(fileread),0)<0)
{
printf("Can't sendn");
}
sleep(1);
}
if(!fgets(fileread,sizeof(fileread),fp))
{
send(newsd,"completed",999999999,0);
}
return(0);
}
}

CLIENT

#include<stdio.h>

main()
{
FILE *fp;
int csd,n,ser,s,cli,cport,newsd;
char name[100],rcvmsg[100],rcvg[100],fname[100];
printf("Enter the port");
scanf("%d",&cport);

if(csd<0)
{
printf("Error...");
exit(0);
}
else
printf("Socket is Created...n");

servaddr.sin_addr.s_addr=htonl(INADDR_ANY);servaddr.sin_port=htons(cport);

printf("Error in Connection...n");
else
printf("Connected...n");
printf("Enter the existing file name: ");
scanf("%s",name);

printf("nEnter the new filename: ");
scanf("%s",fname);

fp=fopen(fname,"w");
send(csd,name,sizeof(name),0);

while(1)
{
s=recv(csd,rcvg,100,0);
rcvg[s]='0';
if(strcmp(rcvg,"error")==0)
printf("File is not Available...n");

if(strcmp(rcvg,"completed")==0) {
printf("file is transferred...n");
fclose(fp);
close(csd);
break;
}
else
fputs(rcvg,stdout);
fprintf(fp,"%s",rcvg);
}
}

OUTPUT:

Server Side

[1me16@localhost ~]$ cc ftpclient.c
Enter the port address:
8663
Socket is Created
Binded
Connected…

Client Side

[1me16@localhost ~]$ cc ftpserver.c
Socket is Created..
Connected
Enter the existing file name: net
Enter the new file name: network
Welcome to Network Lab
File is transferred...

RESULT
Thus the C program for transferring file from one machine to another machine
using TCP is executed and the output is verified successfully.

EX.NO:4 SIMULATION OF SLIDING WINDOW
PROTOCOL

DATE:
AIM
To write a C program for the simulation of Sliding Window Protocol.

ALGORITHM

SENDER

Step 2: Create a Socket for the Sender and bind it with the receiver.
Step 3: Set the size of the window.
Step 4: Send the frames upto the size of the window to the receiver
Step 5: If any of the frames are lost then retransmit those frames to the receiver
Step 6: Stop the execution.

RECEIVER

Step 2: Create the Socket for the Receiver, bind it and listen for the frames from the
sender.
Step 3: If all the frames are successfully received, send the acknowledgement for the last
frame
to the sender.
Step 4: If any of the frames is lost, then send the acknowledgement of the last frame,
which was
successfully received.
Step 5: Keep on receiving and acknowledging the frames until the sender sends.

SLIDING WINDOW PROTOCOL
SERVER
#include<stdio.h>
#include<string.h>
main()
{
int a,bd,sd,newsd,port,clilen;
char lost[20],sendmsg[20],recvmsg[20];
if(sd<0)
else
printf("Enter the port non");
scanf("%d",&port);
a=sizeof(servaddr);
bd=bind(sd,(struct sockaddr*)&servaddr,a);
if(bd<0)
else

listen(sd,5);
newsd=accept(sd,(struct sockaddr*)&cliaddr,&clilen);
if(newsd<0)
else

printf("Enter the lost framen");
scanf("%s",lost);
send(newsd,lost,20,0);
recv(newsd,recvmsg,20,0);
printf("n Frame %s is successfully received",recvmsg);

}

CLIENT
#include<stdio.h>
#include<string.h>
main()
{
int i,sd,n,port;
char sendmsg[100],recvmsg[100];
scanf("%d",&port);
if(sd<0)
else
if(connect(sd,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)
else
printf("Enter the no of framesn");
scanf("%d",&n);
printf("nThe frames alln");
for(i=1;i<=n;i++)
printf("Frame %dn",i);
recv(sd,recvmsg,20,0);
printf("n Lost frame %s is retransmitted ",recvmsg);
strcpy(sendmsg,recvmsg);
send(sd,sendmsg,20,0);
}

OUTPUT:

Server:

[1me16alhost~]: VI swserver.c
[1me16alhost~]: CC swserver.c
[1me16alhost~]: /a.out

8543

Socket is created
Binded
Accepted

Enter the lost frame: 3
Frame tcpserver.c is successfully transmitted

Client:

[1me16alhost~]: VI swclient.c
[1me16alhost~]: CC swclient.c

Enter the client port no
8543

Socket is created
Connected…………..

Enter the no of frames: 4
The frames all
Frame 1/n Frame 2/n Frame 3/n Frame 4/n

RESULT
Thus the C program for the simulation of Sliding Window Protocol has been
executed and the output is verified successfully.

EX.NO:5 DOMAIN NAME SYSTEM

DATE:
AIM
To write a C program for the simulation of Domain Name System

ALGORITHM

SERVER
Step 2: Create the Socket for the Server.
Step 3: Bind the Socket to the Port.
Step 4: Listen for the incoming client connection.
Step 5: Receive the IP address from the client to be resolved.
Step 6: Get the domain name from the client.
Step 7: Check the existence of the domain in the server.
Step 8: If domain matches then send the corresponding address to the client.

CLIENT

Step 2: Create the Socket for the client.
Step 3: Connect the Socket to the server.
Step 4: Send the hostname to the server to be resolved.
Step 5: If the server responds the print the address and terminates the process.

DOMAIN NAME SYSTEM

SERVER
#include<stdio.h>
#include<string.h>
main()
{
int sd,sd2,nsd,clilen,sport,len,i;
char ipid[20][20]={"172.15.64.66","172.15.44.55","172.15.33.44","172.15.22.33"};
char hostid[20][20]={"www.yahoo.com","www.google.com","www.hotmail.com"};
printf("DNS Server Siden");
printf("Enter the Portn");
scanf("%d",&sport);
if(sd<0)
else
if(sd2<0)
printf("Can't Bindn");
else

listen(sd,5);
if(nsd<0)
else
recv(nsd,recvmsg,20,0);
for(i=0;i<4;i++)
{
if(strcmp(recvmsg,hostid[i])==0)
{
send(nsd,ipid[i],20,20);
break; }}}

CLIENT
#include<stdio.h>
main()
{
int csd,cport,len;
printf("DNS Client Siden");
printf("Enter the Client portn");
scanf("%d",&cport);
if(csd<0)
else
else

printf("Enter the host addressn");
scanf("%s",sendmsg);
recv(csd,recvmsg,20,20);
printf("The Coresponding IP Address isn");
printf("%s",recvmsg);

}

OUTPUT:

Server:

[1me16alhost~]: VI dnsserver.c
[1me16alhost~]: CC dnsserver.c

Enter the port no
8543

Socket is created
Binded
Accepted

Client:

[1me16alhost~]: VI dnsclient.c
[1me16alhost~]: CC dnsclient.c

Enter the client port no
8543

Socket is created
Connected…………..

Enter the host address
www.yahoo.com

The corresponding IP Address is
172.15.64.66

RESULT
Thus the C program for the simulation of Domain Name System has been executed

EX.NO:6 SIMULATION OF ROUTING PROTOCOLS

DATE:
AIM
To Simulate Shortest Path Routing Algorithm

ALGORITHM
Step 1: Start the Program

Step 2: Create a distance list, a previous vertex list, a visited list, and a current vertex.

Step 3: All the values in the distance list are set to infinity except the starting vertex
which is set to zero.

Step 4: All values in visited list are set to false.

Step 5: All values in the previous list are set to a special value signifying that they are
undefined.

Step 6: Current node is set as the starting vertex.

Step 7: Mark the current vertex as visited.

Step 8: Update distance and previous lists based on those vertices which can be
immediately reached from the current vertex.

Step 9: Update the current vertex to the unvisited vertex that can be reached by the
shortest path from the starting vertex.

Step 10: Repeat (from step 6) until all nodes are visited.


SIMULATION OF OSPF ROUTING PROTOCOL

#include<iostream.h>
#include<conio.h>
class dij
{
private:
int graph[15][15],source,no;
int set[15],predessor[15],mark[15],pathestimate[15];
public:
int minimum();
void read();
void initialize();
void printpath(int);
void algorithm();
void output();
};

void dij::read()
{
cout<<"Enter the no of vertices: ";
cin>>no;
cout<<"Enter the Adjacent matrices";
for(int i=1;i<=no;i++)
{
cout<<"Enter the weight for row: "<<i;
for(int j=1;j<=no;j++)
{
cin>>graph[i][j];
}
}
cout<<"Enter the source Vector: ";
cin>>source;
}

void dij::initialize()
{
{
mark[i]=0;
pathestimate[i]=999;
predessor[i]=0;
}
pathestimate[source]=0;

}

void dij::algorithm()
{
initialize();
int count=0,i,u;

while(count<no)
{
u=minimum();
set[++count]=u;
mark[u]=1;
{
if(graph[u][i]>0)
{
if(mark[i]!=1)
{
if(pathestimate[i]>pathestimate[u]+graph[u][i])
{
predessor[i]=u;
pathestimate[i]=pathestimate[u]+graph[u][i];
}
}
}
} //for loop
} //while loop
}
void dij::printpath(int i)
{
cout<<endl;
if(i==source)
{
cout<<source;
}
else if(predessor[i]==0)
cout<<"No path from"<<source<<"to"<<i;
else
{
printpath(predessor[i]);
cout<<"....."<<i;
}
}

void dij::output()
{

{
printpath(i);
if(pathestimate[i]!=999)
cout<<"->("<<pathestimate[i]<<")n";
}
cout<<endl;
}

int dij::minimum()
{
int min=999,i,t;
for(i=1;i<=no;i++)
{
if(mark[i]!=1)
{
if(min>=pathestimate[i])
{
min = pathestimate[i];
t=i;
}
}
}
return t;
}

void main()
{
clrscr();
dij d;
d.read();
d.algorithm();
d.output();
getch();
}

OUTPUT
Enter the no of vertices: 3
Enter the Adjacent matrices
Enter the weight for row: 1
0
1
3
2
1
1
2
1
1
Enter the source vector: 1
1 -> (0)
1……. 2- > (1)
1…… 2 ……. 3 -> (1)

RESULT:
Thus the Program for simulating Shortest Path Routing Algorithm is executed

EX.NO:6b UNIFORM RESOURCE LOCATOR (URL)

DATE:
AIM

To retrieve the data using Uniform Resource Locators

ALGORITHM

Step 1: Start the Program.

Step 2: Create an object for the URL class.

Step 3: Specify the address from which the data is to be retrieved inside the URL class

Step 4: Open the URL connection

Step 5: Request the content Length, modified date etc. using appropriate the methods.

Step 6: Display the contents to the user

Step 7: Stop the program

UNIFORM RESOURCE LOCATOR
#include<iostream.h>
#include<stdio.h>
#include<dos.h>
#include<conio.h>
#include<string.h>
void main()
{
char c;
int len=0;
struct date d;
struct time t;
clrscr();
FILE *fp;
getdate(&d);
gettime(&t);
fp=fopen("welcome.html","r");
printf("Content type = text/htmln");
printf("n Date : %d-%d-%d Time : %d:%d:%d
n",d.da_day,d.da_mon,d.da_year,t.ti_hour,t.ti_min,t.ti_sec);
c=fgetc(fp);
cout<<c;
len++;
while((c=fgetc(fp))!=-1)
{
if(c!='n'||' ');
len++;
cout<<c;
}
printf("n Content length is %d",len);
getch();
}

OUTPUT:

CONTENT TYPE=text/html

Date:03-11-2010 time:15:13:28

<html>
<head>
<title>welcome</title>
<body bgcolor=”blue”>
<h1>welcome to network lab-1</h>
</body>
</html>

content length is 109

RESULT
Thus the program for retrieving the data using URL is executed and the output is
verified successfully.

Ex.No:8 MULTICLIENT-SERVER CHAT
Date:
AIM:
To write a C program for implementing Client-Server Chat using TCP.

ALGORITHM:
SERVER:

Step 2: Create an unnamed socket for the server using the parameters AF_INET as
domain and the SOCK_STREAM as type.
Step 3: Name the socket using bind ( ) system call with the parameters server_sockfd and
the server address (sin_addr and sin_sport).
Step 4: Create a connection queue and wait for clients using the listen( ) system call with
the number of clients request as parameters.
Step 5: Get the client‟s id as input from the user to communicate. If the client‟s id is 0
then go to step 10 otherwise go to step 6.
Step 6: Accept the connection using accept ( ) system call when client requests for
connection.
Step 7: Get the message which has to be sent to the client and check that it is not equal to
„Bye‟.
Step 8: If the message is not equal to „Bye‟ then write the message to the client and Goto
step 6.
Step 9: If the message is „Bye‟ then terminates the connection with current client and Go
to
step 5.

CLIENT:

Step 2: Create an unnamed socket for client using socket ( ) system.
Step 5: Now connect the socket to server using connect ( ) system call.
Step 6: Read the message from the server socket and compare it with „Bye‟.
Step 7: If the message is not equal to „Bye‟ then print the message to the server output
device and repeat the steps 6 & 7.
Step 8: Get the message from the client side.
Step 9: Write the message to server sockfd and goto step 4.
Step 10: If the message is equal to „Bye‟then print good bye message and terminate the
process.

MULTI USER CHAT

SERVER
#include<stdio.h>
#include<string.h>
main()
{
int i,sd,sd2,nsd,clilen,sport,len;
printf(“Enter the port no:n”);
scanf("%d",&sport);

if(sd<0)
else

if(sd2<0)
printf("Can't Bindn");
else

listen(sd,5);
do
{
printf("Enter the client no to communicaten");
scanf("%d",&i);
if(i==0)
exit(0);
printf("Client %d is connectedn",i);
if(nsd<0)
else
do

{
recv(nsd,rcvmsg,20,0);
printf("%s",rcvmsg);
sendmsg[len-1]='0';
wait(20);
}while(strcmp(sendmsg,"bye")!=0);
}while(i!=0);
}

CLIENT - 1
#include<stdio.h>

main()
{
int csd,cport,len;
printf("Enter the port no:n");
scanf("%d",&cport);

if(csd<0)
else
else

do
{
sendmsg[len-1]='0';
wait(20);

}
}

CLIENT - 2
#include<stdio.h>

main()
{
int csd,cport,len;
printf("Enter the port no:n");
scanf("%d",&cport);

if(csd<0)
else
else

do
{
sendmsg[len-1]='0';
wait(20);
}
}

OUTPUT:

SERVER SIDE:

[1me2@localhost ~]$ vi Multiuserserver.c
[1me2@localhost ~]$ cc Multiuserserverc
[1me2@localhost ~]$ ./a.out

Enter the port no
8543

socket is created
Binded

Enter the client to communicate: 1
Client 1 is connected
Accepted
hiiiii
Byeeeeee

Enter the client no to communicate: 2
client 2 is connected
Accepted
hiiiiiiiiii
hello

Enter the client no to communicate: 0

CLIENT SIDE 1:

[1me2@localhost ~]$ vi multiuserclient1.c
[1me2@localhost ~]$ cc multiuserclient1.c

Enter the port no
8543

Socket is created
Connected
hiiiiii
Byeeeee

CLIENT SIDE –2:

[1me2@localhost ~]$ vi multiuserclient2.c
[1me2@localhost ~]$ cc multiuserclient2.c

Enter the port no
8543
Socket is created
Connected
Hiiiiiiiii
hello

RESULT
Thus the C program for chat multiclient-serve chat program using tcp has been
executed successfully.

Ex. No:9 SIMULATION OF SIMPLE NETWORK
Date: MANAGEMENT PROTOCOLS

AIM:
To write a C program for simulation of Simple Network management Protocols.

ALGORITHM:
MANAGER:

Step 2: Create an unnamed socket for client using socket ( ) system.
Step 4: Name the socket using bind ( ) system call.
Step 5: Now connect the socket to agent using connect ( ) system call.
Step 6: Get the input for the type of information needed from the agent.
Step 7: If the input is equal to „TCP connection‟ then goto next step else If it is equal to
„system‟ Goto step 9.
Step 8: Read the input for the object, send it and receive the details of the TCP
connection of that object from the agent. Go to step 10.
Step 9: Read the input for the object, send it and receive the details of the system from
the agent. Go to step 10.
Step 10: Receive the message, print and terminate the process.

AGENTS
Step 2: Create an unnamed socket for the server using the parameters AF_INET as
domain and the SOCK_STREAM as type.
Step 3: Name the socket using bind( ) system call with the parameters server_sockfd
and the manager address(sin_addr and sin_sport).
Step 4: Create a connection queue and wait for manager using the listen ( ) system call
with the number of manager request as parameters.
Step 5: Accept the connection using accept( ) system call when manager requests for
connection.
Step 6: Receive the message from the manager. If the request is for „TCP connections‟
then send the details of the requested object, else if the request is for „System‟ then send
the details of the requested system.

SIMPLE NETWORK MANAGEMENT PROTOCOL
AGENT1

#include<stdio.h>
#include<string.h>

main()
{
char oid[5][10]={"client1","client2","client3","cleint4","client5"};
char wsize[5][5]={"5","10","15","3","6"};
printf("I'm the Agent - TCP Connectionn");
printf("nEnter the Server port");
printf("n_____________________n");
scanf("%d",&sport);

if(sd<0)
else
if(sd2<0)
else

listen(sd,5);

if(nsd<0)
else
for (i=0;i<5;i++)
{

if(strcmp(recvmsg,oid[i])==0)
{
send(nsd,wsize[i],100,0);
break;
}
}
}

AGENT 2

#include<stdio.h>
#include<string.h>

main()
{
char oid[5][10]={"System1","System2","System3","System4","System5"};
char mdate[5][15]={"1-10-095","10-03-08","14.03.81","11.07.07","17.12.77"};
char time[5][15]={"9am","10pm","11am","12.30pm","11.30am"};
printf("Enter the Server port");
printf("n_____________________n");
scanf("%d",&sport);

if(sd<0)
else

if(sd2<0)
else

listen(sd,5);

if(nsd<0)
else


for(i=0;i<5;i++)
{
if(strcmp(recvmsg,oid[i])==0)
{
send(nsd,mdate[i],100,0);
send(nsd,time[i],100,0);
break;
}
}
}

MANAGER
#include<stdio.h>

main()
{
int csd,cport,len,i;
char sendmsg[20],rcvmsg[100],rmsg[100],oid[100];
scanf("%d",&cport);

if(csd<0)
else

else

printf("n 1.TCP Connectionn");
printf("n 2. System n");
printf("Enter the number for the type of informtion needed....n");
scanf("%d",&i);
if(i==1)
{
printf("Enter the Object ID for Clientn");
scanf("%s",oid);
send(csd,oid,100,0);
recv(csd,rmsg,100,0);
printf("n The window size of %s is %s",oid,rmsg);
}
else
{
printf("nEnter the Object ID for the Systemn");
scanf("%s",oid);
send(csd,oid,100,0);
printf("nThe Manufacturing date for %s is %s",oid,rmsg);
printf("nThe time of Last Utilization for %s is %s",oid,rmsg);
}
}

OUTPUT:
AGENT1:

[1me14@localhost ~]$ vi Agent1.c
[1me14@localhost ~]$ cc Agent1.c
I'm the Agent - TCP Connection

Enter the Server port
_____________________
8543
Socket is created
Binded
Accepted

MANGER:

[1me14@localhost ~]$ vi Manager.c
[1me14@localhost ~]$ cc Manger.c
Enter the port
8543

Socket is Created
Connected

1.TCP Connection
2. System
Enter the number for the type of information needed: 1
Enter the Object ID for Client: Client1

The window size of client1 is 5

AGENT2:

[1me14@localhost ~]$ vi Agent2.c
[1me14@localhost ~]$ cc Agent2.c
Enter the Server port
_____________________
8543
Socket is Created
Binded
Accepted

MANGER:

[1me14@localhost ~]$ vi Manager.c
[1me14@localhost ~]$ cc Manger.c
Enter the port
8543

Socket is Created
Connected

1.TCP Connection

2. System
Enter the number for the type of informtion needed: 2
Enter the Object ID for Client: System3

The Manufacturing date for system3 is 14.03.81
The time of last utilization for system3 is 11am

RESULT
Thus the C program for simple network management protocols has been executed
successfully.

EMAIL

#include <stdlib.h>
#include <string.h>
#define cknull(x) if((x)==NULL) {perror(""); exit(EXIT_FAILURE);}
#define cknltz(x) if((x)<0) {perror(""); exit(EXIT_FAILURE);}
#define LIST_LEN 4
//char *f="sam.txt";
void email_it(char *filename);

main()
{
char fname[15];
printf("enter the filenamen");
scanf("%s",fname);
email_it(fname);
}

void email_it(char *filename)
{
char tmp[256]={0x0};
char fpBuffer[400]={0x0};
char email_list[LIST_LEN][256]={{"mecse3@localhost.localdomain"},{0x0}};
int i=0;

for(i=0;*email_list[i]>0x0;i++)
{
cknull(strcpy(tmp, email_list[i]));
cknltz(sprintf (fpBuffer,"mail -s '%s %s' %s < %s",
"Please Review:", filename, tmp,filename));

if(system (fpBuffer)==(-1))
{
perror("email failure");
exit(EXIT_FAILURE);
}
}
}

OUTPUT:

[1me2@localhost ~]$ vi email.c
[1me2@localhost ~]$ cc email.c

Enter the file name: sample.c

[1me2@localhost ~]$/home/1me1/dead.letter….saved message in
/home/1me1/dead.letter…..

RESULT
Thus the program for developing E-mail application is executed and the output is
verified successfully.

STUDY OF NETWORK SIMULATOR PACKAGES

Ex. No: STUDY OF NS2
Date:
AIM:
To study about NS2 - Network Simulator

INTRODUCTION:
NS is a discrete event simulator targeted at networking research. NS provides
substantial support for simulation of TCP, routing, and multicast protocols over wired
and wireless (local and satellite) networks. NS began as a variant of the REAL network
simulator in 1989 and has evolved substantially over the past few years. In 1995 ns
development was supported by DARPA through the VINT project at LBL, Xerox PARC,
UCB, and USC/ISI. Currently ns development is support through DARPA with SAMAN
and through NSF with CONSER, both in collaboration with other researchers including
ACIRI. NS has always included substantial contributions from other researchers,
including wireless code from the UCB Daedelus and CMU Monarch projects and Sun
Microsystems.
The network simulator ns-2 is a widely accepted discrete event network simulator,
actively used for wired and wireless network simulations. It has a highly detailed model
of the lower layers (Physical and MAC) of wireless IEEE 802.11 networks.
Ns-2 has also an emulation feature, i.e. the ability to introduce the simulator into a
live network and to simulate a desired network between real applications in real-time.
Within the scope of this project we developed some methods and extensions to
the ns-2 to combine wireless network simulation and network emulation.

OVERVIEW:
NS is an event driven network simulator developed at UC Berkeley that simulates
variety of IP networks. It implements network protocols such as TCP and UDP, traffic
source behavior such as FTP, Telnet, Web, CBR and VBR, router queue management
mechanism such as Drop Tail, RED and CBQ, routing algorithms such as Dijkstra, and
more. NS also implements multicasting and some of the MAC layer protocols for LAN
simulations. The NS project is now a part of the VINT project that develops tools for
simulation results display, analysis and converters that convert network topologies
generated by well-known generators to NS formats. Currently, NS (version 2) written in
C++ and OTcl (Tcl script language with Object-oriented extensions developed at MIT) is
available. This document talks briefly about the basic structure of NS, and explains in
detail how to use NS mostly by giving examples. Most of the figures that are used in
describing the NS basic structure and network components are from the 5th VINT/NS
Simulator Tutorial/Workshop slides and the NS Manual (formerly called "NS Notes and
Documentation"), modified little bit as needed.

Figure 1. Simplified User's View of NS

As shown in Figure 1, in a simplified user's view, NS is Object-oriented Tcl
(OTcl) script interpreter that has a simulation event scheduler and network component
object libraries, and network setup (plumbing) module libraries (actually, plumbing
modules are implemented as member functions of the base simulator object). In other
words, to use NS, you program in OTcl script language. To setup and run a simulation
network, a user should write an OTcl script that initiates an event scheduler, sets up the
network topology using the network objects and the plumbing functions in the library,
and tells traffic sources when to start and stop transmitting packets through the event
scheduler. The term "plumbing" is used for a network setup, because setting up a network
is plumbing possible data paths among network objects by setting the "neighbor" pointer
of an object to the address of an appropriate object. When a user wants to make a new
network object, he or she can easily make an object either by writing a new object or by
making a compound object from the object library, and plumb the data path through the
object. This may sound like complicated job, but the plumbing OTcl modules actually
make the job very easy. The power of NS comes from this plumbing.
Another major component of NS beside network objects is the event scheduler.
An event in NS is a packet ID that is unique for a packet with scheduled time and the
pointer to an object that handles the event. In NS, an event scheduler keeps track of
simulation time and fires all the events in the event queue scheduled for the current time
by invoking appropriate network components, which usually are the ones who issued the
events, and let them do the appropriate action associated with packet pointed by the
event. Network components communicate with one another passing packets, however this
does not consume actual simulation time. All the network components that need to spend
some simulation time handling a packet (i.e. need a delay) use the event scheduler by
issuing an event for the packet and waiting for the event to be fired to itself before doing
further action handling the packet. For example, a network switch component that
simulates a switch with 20 microseconds of switching delay issues an event for a packet
to be switched to the scheduler as an event 20 microsecond later. The scheduler after 20
microseconds dequeues the event and fires it to the switch component, which then passes
the packet to an appropriate output link component. Another use of an event scheduler is
timer.
NS is written not only in OTcl but in C++ also. For efficiency reason, NS
separates the data path implementation from control path implementations. In order to

reduce packet and event processing time (not simulation time), the event scheduler and
the basic network component objects in the data path are written and compiled using
C++. These compiled objects are made available to the OTcl interpreter through an OTcl
linkage that creates a matching OTcl object for each of the C++ objects and makes the
control functions and the configurable variables specified by the C++ object act as
member functions and member variables of the corresponding OTcl object. In this way,
the controls of the C++ objects are given to OTcl. It is also possible to add member
functions and variables to a C++ linked OTcl object. The objects in C++ that do not need
to be controlled in a simulation or internally used by another object do not need to be
linked to OTcl. Likewise, an object (not in the data path) can be entirely implemented in
OTcl. Figure 2 shows an object hierarchy example in C++ and OTcl. One thing to note in
the figure is that for C++ objects that have an OTcl linkage forming a hierarchy, there is a
matching OTcl object hierarchy very similar to that of C++.

Figure 2. C++ and OTcl: The Duality

Figure 3. Architectural View of NS

Figure 3 shows the general architecture of NS. In this figure a general user (not an
NS developer) can be thought of standing at the left bottom corner, designing and
running simulations in Tcl using the simulator objects in the OTcl library. The event
schedulers and most of the network components are implemented in C++ and available to
OTcl through an OTcl linkage that is implemented using tclcl. The whole thing together
makes NS, which is a OO extended Tcl interpreter with network simulator libraries.
This section briefly examined the general structure and architecture of NS. At this
point, one might be wondering about how to obtain NS simulation results.

As shown in Figure 1, when a simulation is finished, NS produces one or more
text-based output files that contain detailed simulation data, if specified to do so in the
input Tcl (or more specifically, OTcl) script. The data can be used for simulation analysis
(two simulation result analysis examples are presented in later sections) or as an input to
a graphical simulation display tool called Network Animator (NAM) that is developed as
a part of VINT project. NAM has a nice graphical user interface similar to that of a CD
player (play, fast forward, rewind, pause and so on), and also has a display speed
controller. Furthermore, it can graphically present information such as throughput and
number of packet drops at each link, although the graphical information cannot be used
for accurate simulation analysis.
This section shows a simple NS simulation script and explains what each line does.
Example 3 is an OTcl script that creates the simple network configuration and runs the
simulation scenario in Figure 4.

Figure 4. A Simple Network Topology and Simulation Scenario
This network consists of 4 nodes (n0, n1, n2, n3) as shown in above figure. The
duplex links between n0 and n2, and n1 and n2 have 2 Mbps of bandwidth and 10 ms of
delay. The duplex link between n2 and n3 has 1.7 Mbps of bandwidth and 20 ms of
delay. Each node uses a DropTail queue, of which the maximum size is 10. A "tcp" agent
is attached to n0, and a connection is established to a tcp "sink" agent attached to n3. As
default, the maximum size of a packet that a "tcp" agent can generate is 1KByte. A tcp
"sink" agent generates and sends ACK packets to the sender (tcp agent) and frees the
received packets. A "udp" agent that is attached to n1 is connected to a "null" agent
attached to n3. A "null" agent just frees the packets received.

Example 3. A Simple NS Simulation Script

The following is the explanation of the script above. In general, an NS script starts
with making a Simulator object instance.
set ns [new Simulator]: generates an NS simulator object instance, and assigns it
to variable ns (italics is used for variables and values in this section).
o Initialize the packet format (ignore this for now)
o Create a scheduler (default is calendar scheduler)
o Select the default address format (ignore this for now)

The "Simulator" object has member functions that do the following:
 Create compound objects such as nodes and links (described later)
 Connect network component objects created (ex. attach-agent)
 Set network component parameters (mostly for compound objects)
 Create connections between agents (ex. make connection between a "tcp" and
"sink")
 Specify NAM display options

Most of member functions are for simulation setup and scheduling, however some of
them are for the NAM display. The "Simulator" object member function implementations
are located in the "ns-2/tcl/lib/ns-lib.tcl" file.
$ns color fid color: is to set color of the packets for a flow specified by the flow id
(fid). This member function of "Simulator" object is for the NAM display, and
has no effect on the actual simulation.
$ns namtrace-all file-descriptor: This member function tells the simulator to
record simulation traces in NAM input format. It also gives the file name that the
trace will be written to later by the command $ns flush-trace. Similarly, the
member function trace-all is for recording the simulation trace in a general
format.
proc finish {}: is called after this simulation is over by the command $ns at 5.0
"finish". In this function, post-simulation processes are specified.

set n0 [$ns node]: The member function node creates a node. A node in NS is
compound object made of address and port classifiers (described in a later
section). Users can create a node by separately creating an address and a port
classifier objects and connecting them together. However, this member function
of Simulator object makes the job easier. To see how a node is created, look at the
files: "ns-2/tcl/libs/ns-lib.tcl" and "ns-2/tcl/libs/ns-node.tcl".
$ns duplex-link node1 node2 bandwidth delay queue-type: creates two simplex
links of specified bandwidth and delay, and connects the two specified nodes. In
NS, the output queue of a node is implemented as a part of a link, therefore users
should specify the queue-type when creating links. In the above simulation script,
DropTail queue is used. If the reader wants to use a RED queue, simply replace
the word DropTail with RED. The NS implementation of a link is shown in a later
section. Like a node, a link is a compound object, and users can create its sub-
objects and connect them and the nodes. Link source codes can be found in "ns-

2/tcl/libs/ns-lib.tcl" and "ns-2/tcl/libs/ns-link.tcl" files. One thing to note is that
you can insert error modules in a link component to simulate a lossy link (actually
users can make and insert any network objects). Refer to the NS documentation to
find out how to do this.
$ns queue-limit node1 node2 number: This line sets the queue limit of the two
simplex links that connect node1 and node2 to the number specified. At this point,
the authors do not know how many of these kinds of member functions of
Simulator objects are available and what they are. Please take a look at "ns-
2/tcl/libs/ns-lib.tcl" and "ns-2/tcl/libs/ns-link.tcl", or NS documentation for more
information.
$ns duplex-link-op node1 node2 ...: The next couple of lines are used for the
NAM display. To see the effects of these lines, users can comment these lines out
and try the simulation.
Now that the basic network setup is done, the next thing to do is to setup traffic
agents such as TCP and UDP, traffic sources such as FTP and CBR, and attach them to
nodes and agents respectively.
set tcp [new Agent/TCP]: This line shows how to create a TCP agent. But in
general, users can create any agent or traffic sources in this way. Agents and
traffic sources are in fact basic objects (not compound objects), mostly
implemented in C++ and linked to OTcl. Therefore, there are no specific
Simulator object member functions that create these object instances. To create
agents or traffic sources, a user should know the class names these objects
(Agent/TCP, Agnet/TCPSink, Application/FTP and so on). This information can
be found in the NS documentation or partly in this documentation. But one
shortcut is to look at the "ns-2/tcl/libs/ns-default.tcl" file. This file contains the
default configurable parameter value settings for available network objects.
Therefore, it works as a good indicator of what kind of network objects are
available in NS and what are the configurable parameters.
$ns attach-agent node agent: The attach-agent member function attaches an agent
object created to a node object. Actually, what this function does is call the attach
member function of specified node, which attaches the given agent to itself.
Therefore, a user can do the same thing by, for example, $n0 attach $tcp.
$ns connect agent1 agent2: After two agents that will communicate with each
other are created, the next thing is to establish a logical network connection
between them. This line establishes a network connection by setting the
destination address to each others' network and port address pair.
Assuming that all the network configuration is done, the next thing to do is write a
simulation scenario (i.e. simulation scheduling). The Simulator object has many
scheduling member functions. However, the one that is mostly used is the following:
$ns at time "string": This member function of a Simulator object makes the
scheduler (scheduler_ is the variable that points the scheduler object created by
[new Scheduler] command at the beginning of the script) to schedule the
execution of the specified string at given simulation time. For example, $ns at 0.1
"$cbr start" will make the scheduler call a start member function of the CBR
traffic source object, which starts the CBR to transmit data. In NS, usually a

traffic source does not transmit actual data, but it notifies the underlying agent
that it has some amount of data to transmit, and the agent, just knowing how
much of the data to transfer, creates packets and sends them.
After all network configuration, scheduling and post-simulation procedure specifications
are done, the only thing left is to run the simulation. This is done by $ns run.

NETWORK COMPONENTS:

Figure 6. Class Hierarchy (Partial)

The root of the hierarchy is the TclObject class that is the superclass of all OTcl
library objects (scheduler, network components, timers and the other objects including
NAM related ones). As an ancestor class of TclObject, NsObject class is the superclass of
all basic network component objects that handle packets, which may compose compound
network objects such as nodes and links. The basic network components are further
divided into two subclasses, Connector and Classifier, based on the number of the
possible output data paths. The basic network objects that have only one output data path
are under the Connector class, and switching objects that have possible multiple output
data paths are under the Classifier class.

NODE AND ROUTING:
A node is a compound object composed of a node entry object and classifiers as
shown in Figure 7. There are two types of nodes in NS. A unicast node has an address
classifier that does unicast routing and a port classifier. A multicast node, in addition, has

a classifier that classify multicast packets from unicast packets and a multicast classifier
that performs multicast routing.

Figure 7. Node (Unicast and Multicast)

In NS, Unicast nodes are the default nodes. To create Multicast nodes the user
must explicitly notify in the input OTcl script, right after creating a scheduler object, that
all the nodes that will be created are multicast nodes. After specifying the node type, the
user can also select a specific routing protocol other than using a default one.

 Unicast
- $ns rtproto type
- type: Static, Session, DV, cost, multi-path

Multicast
- $ns multicast (right after set $ns [new Scheduler])
- $ns mrtproto type
- type: CtrMcast, DM, ST, BST

LINK:
A link is another major compound object in NS. When a user creates a link using a
duplex-link member function of a Simulator object, two simplex links in both directions
are created as shown in Figure 8.

Figure 8. Link

One thing to note is that an output queue of a node is actually implemented as a
part of simplex link object. Packets dequeued from a queue are passed to the Delay object
that simulates the link delay, and packets dropped at a queue are sent to a Null Agent and
are freed there. Finally, the TTL object calculates Time To Live parameters for each
packet received and updates the TTL field of the packet.
Tracing
In NS, network activities are traced around simplex links. If the simulator is
directed to trace network activities (specified using $ns trace-all file or $ns namtrace-all
file), the links created after the command will have the following trace objects inserted as
shown in Figure 9. Users can also specifically create a trace object of type type between
the given src and dst nodes using the create-trace {type file src dst} command.

Figure 9. Inserting Trace Objects

When each inserted trace object (i.e. EnqT, DeqT, DrpT and RecvT) receives a
packet, it writes to the specified trace file without consuming any simulation time, and
passes the packet to the next network object. The trace format will be examined in the
General Analysis Example section.

Queue Monitor
Basically, tracing objects are designed to record packet arrival time at which they
are located. Although a user gets enough information from the trace, he or she might be
interested in what is going on inside a specific output queue. For example, a user
interested in RED queue behavior may want to measure the dynamics of average queue
size and current queue size of a specific RED queue (i.e. need for queue monitoring).
Queue monitoring can be achieved using queue monitor objects and snoop queue objects
as shown in Figure 10.

Figure 10. Monitoring Queue

When a packet arrives, a snoop queue object notifies the queue monitor object of
this event. The queue monitor using this information monitors the queue. A RED queue
monitoring example is shown in the RED Queue Monitor Example section. Note that
snoop queue objects can be used in parallel with tracing objects even though it is not
shown in the above figure.

PACKET FLOW EXAMPLE:
Until now, the two most important network components (node and link) were
examined. Figure 11 shows internals of an example simulation network setup and packet
flow. The network consist of two nodes (n0 and n1) of which the network addresses are 0
and 1 respectively. A TCP agent attached to n0 using port 0 communicates with a TCP
sink object attached to n1 port 0. Finally, an FTP application (or traffic source) is
attached to the TCP agent, asking to send some amount of data.

Figure 11. Packet Flow Example

Note that the above figure does not show the exact behavior of a FTP over TCP. It
only shows the detailed internals of simulation network setup and a packet flow.

PACKET:
A NS packet is composed of a stack of headers, and an optional data space (see
Figure 12). As briefly mentioned in the "Simple Simulation Example" section, a packet

header format is initialized when a Simulator object is created, where a stack of all
registered (or possibly useable) headers, such as the common header that is commonly
used by any objects as needed, IP header, TCP header, RTP header (UDP uses RTP
header) and trace header, is defined, and the offset of each header in the stack is recorded.
What this means is that whether or not a specific header is used, a stack composed of all
registered headers is created when a packet is allocated by an agent, and a network object
can access any header in the stack of a packet it processes using the corresponding offset
value.

Figure 12. NS Packet Format

Usually, a packet only has the header stack (and a data space pointer that is null).
Although a packet can carry actual data (from an application) by allocating a data space,
very few application and agent implementations support this. This is because it is
meaningless to carry data around in a non-real-time simulation. However, if you want to
implement an application that talks to another application cross the network, you might
want to use this feature with a little modification in the underlying agent implementation.
Another possible approach would be creating a new header for the application and
modifying the underlying agent to write data received from the application to the new
header. The second approach is shown as an example in a later section called "Add New
Application and Agent".

RESULT:
Thus the details about NS2(Network Simulator 2) has been studied.

Ex. No. STUDY OF OPNET
Date:
AIM:
To study about OPNET - Network Simulator

INTRODUCTION:
OPNET (Optimized Network Engineering Tools) is a commercial tool from MIL3
Inc. It is being developed for almost 15 years. As everyone should guess, no much
technical detail are available about the internals.

USE:
Network with several hundreds of nodes can be simulated, but it would take time
for the computation. OPNET is used by companies like Thomson-CSF or CNET which
use it to model ATM networks and validate various layers protocols, packet switched
radio networks. An example of use of OPNET is George Mason University (Quality of
Service IP Network Simulation).

THE PACKAGE
The software comprises several tools and is divided in several parts, OPNET
Modeler and OPNET Planner, the Model Library, and the Analysis tool. Features
included in this generic simulator are an event-driven scheduled simulation kernel,
integrated analysis tools for interpreting and synthesizing output data, graphical
specification of models and a hierarchical object-based modeling.
OPNET Modeler is intended for modeling, simulating and analyzing the
performance of large communications networks, computer systems and applications.
Common uses are assessing and feasibility of new designs, optimizing already developed
communication systems and predicting performance.
The modeling methodology of OPNET is organized in a hierarchical structure. At
the lowest level, Process models are structured as a finite state machine. State and
transitions are specified graphically using state-transition diagrams whereas conditions
that specify what happen within each state are programmed with a C-like language called
Proto-C. Those processes and built-in modules in OPNET (source and destination
modules, traffic generators, queues, ...) are then configured with menus and organized
into data flow diagrams that represent nodes using the graphical Node Editor. Using a
graphical Network Editor, nodes and links are selected to build up the topology of a
communication network.
The Analysis Tool provides a graphical environment to view and manipulate data
collected during simulation runs. Results can be analyzed for any network element.
OPNET Planner is an application that allows administrators to evaluate the
performance of communications networks and distributed systems, without programming
or compiling. Planner analyses behavior and performance by discrete-event simulations.
Models are built using a graphical interface. The user only chooses pre-defined models
(from the physical layer to the application) from the library and sets attributes. The user
cannot define new models, he should contact MIL3's modeling service.

The modeling libraries are included with OPNET Modeler and OPNET Planner
and contains protocols and analysis environments, among them ATM, TCP, IP, Frame
Relay, FDDI, Ethernet, link models such as point-to-point or bus, queueing service
disciplines such as First-in-First-Out (FIFO), Last-In-First-Out (LIFO), priority non-
preemptive queueing, shortest first job, round-robin or preempt and resume.
OPNET Modeler is the industry's leading environment for network modeling and
simulation, allowing you to design and study communication networks, devices,
protocols, and applications with unmatched flexibility and scalability. Modeler is used by
the world's largest network equipment manufacturers to accelerate the R&D of network
devices and technologies such as VoIP, TCP, OSPFv3, MPLS, IPv6, and more.
Networking technology has become too complex for traditional analytical
methods or "rules of thumb" to yield an accurate understanding of system behavior.
Since 1986, OPNET Technologies Inc., has been the leader in developing
predictive software solutions for networking professionals. OPNET software enables its
users to optimize the performance and maximize the availability of communications
networks and applications.
OPNET is the state-of-art network simulation tool for modeling, simulating and analysing
the performance of
i. Communication Networks, Distributed Systems
ii. Computer systems and Applications.

Product modules provide value-added capabilities to OPNET's intelligent network
management software. Modules span a wide range of applications and receive regular
updates under OPNET's maintenance program.

OPNET MODULES:
 Modeler
 Terrain Modeling Module (TMM)
 High Level Architecture (HLA)

MODELER:
OPNET Modeler is intended for modeling, simulating and analysing the
performance of large communications networks, computer systems and applications.
Common uses are assessing and feasibility of new designs, optimizing already developed
communication systems and predicting performance.
The modeling methodology of OPNET is organized in a hierarchical structure. At
the lowest level, Process models are structured as a finite state machine. State and
transitions are specified graphically using state-transition diagrams whereas conditions
that specify what happen within each state are programmed with a C-like language called
Proto-C. Those processes, and built-in modules in OPNET (source and destination
modules, traffic generators, queues, ...) are then configured with menus and organized
into data flow diagrams that represent nodes using the graphical Node Editor. Using a
graphical Network Editor, nodes and links are selected to build up the topology of a
communication network.

TERRAIN MODELING MODULE (TMM)
Building on the capabilities of OPNET's Wireless Module, the Terrain Modeling
Module provides the next level of accuracy and control for wireless network design and
planning. This module allows you to model environmental effects on wireless network
communications anywhere.
Featuring an open-source Longley-Rice model, the Terrain Modeling Module is
ready to replicate any known atmospheric or topological conditions and their combined
impact on signal propagation. Create elevation maps, line-of-sight profiles, and signal-
power comparisons of mobile network models. Interfaces to read DTED and USGS DEM
terrain data are provided. Open and flexible, the Terrain Modeling Module is supported
by the standard Radio Transceiver Pipeline, which enables easy implementation of
custom propagation models

HIGH LEVEL ARCHITECTURE (HLA)
The High-Level Architecture (HLA) Module supports building and running a
federation of many simulators, each modeling some aspect of a composite system. The
OPNET HLA Module enables OPNET simulations to model some portion (or the
entirety) of the communications aspects of the HLA federation models. The OPNET-
HLA interface provides the various simulators (federates) the necessary mechanisms to
share a common object representation (for persistent elements), to exchange messages
(interactions), and to maintain appropriate time synchronization.

The module supports a large subset of the HLA interface, including:
 Time management such that an OPNET simulation remains synchronized with
overall HLA time
 Generation and reception of RTI interactions using OPNET packet
 Creation, destruction, or discovery of RTI objects during the simulation
 Generation of RTI object attribute updates based on changes to OPNET attribute
values
 Automatic updates of OPNET attributes upon reception of RTI object attribute
updates
 A user-defined mapping specifying the relation between RTI and OPNET objects

RESULT:
Thus the Network Simulator-OPNET has been studied.

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