Program to Simulate Selective Repeat Sliding Window Protocol.
Simulate and Implement Selective Repeat Sliding Window Protocol using C++.
Program:
- C++
- C
- Java
- Python
- C#
- PHP
- Javascript
/*------------------------------------------------------------------- Simulate Selective Repeat Sliding Window Protocol Program Using C++ --------------------------------------------------------------------*/
#include <iostream>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
using namespace std;
#define TOT_FRAMES 500
#define FRAMES_SEND 10
class sel_repeat
{
private:
int fr_send_at_instance;
int arr[TOT_FRAMES];
int send[FRAMES_SEND];
int rcvd[FRAMES_SEND];
char rcvd_ack[FRAMES_SEND];
int sw;
int rw; // tells expected frame
public:
void input();
void sender(int);
void reciever(int);
};
void sel_repeat :: input()
{
int n; // no of bits for the frame
int m; // no of frames from n bits
cout << "Enter the no of bits for the sequence number ";
cin >> n;
m = pow (2 , n);
int t = 0;
fr_send_at_instance = (m / 2);
for (int i = 0 ; i < TOT_FRAMES ; i++)
{
arr[i] = t;
t = (t + 1) % m;
}
for (int i = 0 ; i < fr_send_at_instance ; i++)
{
send[i] = arr[i];
rcvd[i] = arr[i];
rcvd_ack[i] = 'n';
}
rw = sw = fr_send_at_instance;
sender(m);
}
void sel_repeat :: sender(int m)
{
for (int i = 0 ; i < fr_send_at_instance ; i++)
{
if ( rcvd_ack[i] == 'n' )
cout << " SENDER : Frame " << send[i] << " is sent\n";
}
reciever (m);
}
void sel_repeat :: reciever(int m)
{
time_t t;
int f;
int f1;
int a1;
char ch;
srand((unsigned) time(&t));
for (int i = 0 ; i < fr_send_at_instance ; i++)
{
if (rcvd_ack[i] == 'n')
{
f = rand() % 10;
// if = 5 frame is discarded for some reason
// else frame is correctly recieved
if (f != 5)
{
for (int j = 0 ; j < fr_send_at_instance ; j++)
if (rcvd[j] == send[i])
{
cout << "RECIEVER : Frame " << rcvd[j] << " recieved correctly\n";
rcvd[j] = arr[rw];
rw = (rw + 1) % m;
break;
}
if (j == fr_send_at_instance)
cout << "RECIEVER : Duplicate frame " << send[i] << " discarded\n";
a1 = rand() % 5;
// if a1 == 3 then ack is lost
// else recieved
if (a1 == 3)
{
cout << "(Acknowledgement " << send[i] << " lost)\n";
cout << " (SENDER TIMEOUTS --> RESEND THE FRAME)\n";
rcvd_ack[i] = 'n';
}
else
{
cout << "(Acknowledgement " << send[i] << " recieved)\n";
rcvd_ack[i] = 'p';
}
}
else
{
int ld = rand() % 2;
// if = 0 then frame damaged
// else frame lost
if (ld == 0)
{
cout << "RECIEVER : Frame " << send[i] << " is damaged\n";
cout << "RECIEVER : Negative acknowledgement " << send[i] << " sent\n";
}
else
{
cout << "RECIEVER : Frame " << send[i] << " is lost\n";
cout << " (SENDER TIMEOUTS --> RESEND THE FRAME)\n";
}
rcvd_ack[i] = 'n';
}
}
}
for ( int j = 0 ; j < fr_send_at_instance ; j++)
{
if (rcvd_ack[j] == 'n')
break;
}
i = 0 ;
for (int k = j ; k < fr_send_at_instance ; k++)
{
send[i] = send[k];
if (rcvd_ack[k] == 'n')
rcvd_ack[i] = 'n';
else
rcvd_ack[i] = 'p';
i++;
}
if ( i != fr_send_at_instance )
{
for ( int k = i ; k < fr_send_at_instance ; k++)
{
send[k] = arr[sw];
sw = (sw + 1) % m;
rcvd_ack[k] = 'n';
}
}
cout << "Want to continue...";
cin >> ch;
cout << "\n";
if (ch == 'y')
sender(m);
else
exit(0);
}
void main()
{
sel_repeat sr;
sr.input();
getch();
} |
Output
Enter the no of bits for the sequence number 6
SENDER : Frame 24 is sent
SENDER : Frame 32 is sent
SENDER : Frame 32 is sent
SENDER : Frame 27 is sent
SENDER : Frame 28 is sent
SENDER : Frame 29 is sent
SENDER : Frame 30 is sent
SENDER : Frame 31 is sent
RECIEVER : Frame 24 is lost
(SENDER TIMEOUTS --> RESEND THE FRAME)
RECIEVER : Frame 32 recieved correctly
(Acknowledgement 32 recieved)
RECIEVER : Frame 33 recieved correctly
(Acknowledgement 34 recieved)
RECIEVER : Frame 27 recieved correctly
(Acknowledgement 34 recieved)
RECIEVER : Frame 28 is damaged
RECIEVER : Negative acknowledgement 28 sent
RECIEVER : Frame 29 recieved correctly
(Acknowledgement 35 recieved)
RECIEVER : Frame 30 recieved correctly
(Acknowledgement 36 lost)
(SENDER TIMEOUTS --> RESEND THE FRAME)
RECIEVER : Frame 31 recieved correctly
(Acknowledgement 37 recieved)
Want to continue...n
