Program to go back n sliding window protocol.
Program to Simulate and Implement Go Back n Sliding Window Protocol Using C++.
Program:
- C++
- C
- Java
- Python
- C#
- PHP
- Javascript
/*------------------------------------------------------------ Simulate Go Back n 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 gobkn
{
private:
int fr_send_at_instance;
int arr[TOT_FRAMES];
int arr1[FRAMES_SEND];
int sw;
int rw; // tells expected frame
public:
gobkn();
void input();
void sender(int);
void reciever(int);
};
gobkn :: gobkn()
{
sw = 0;
rw = 0;
}
void gobkn :: 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 no ";
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;
}
sender(m);
}
void gobkn :: sender(int m)
{
int j = 0;
for (int i = sw ; i < sw + fr_send_at_instance ; i++)
{
arr1[j] = arr[i];
j++;
}
for (i = 0 ; i < j ; i++)
cout << " SENDER : Frame " << arr1[i] << " is sent\n";
reciever (m);
}
void gobkn :: reciever(int m)
{
time_t t;
int f;
int f1;
int a1;
char ch;
srand((unsigned) time(&t));
f = rand() % 10;
// if = 5 frame is discarded for some reason
// else they are correctly recieved
if(f != 5)
{
for (int i = 0 ; i < fr_send_at_instance ; i++)
{
if (rw == arr1[i])
{
cout << "RECIEVER : Frame " << arr1[i] << " recieved correctly\n";
rw = (rw + 1) % m;
}
else
cout << "RECIEVER : Duplicate frame " << arr1[i] << " discarded\n";
}
a1 = rand() % 15;
// if a1 belongs to 0 to 3 then all ack after this (incl this one) lost else all recieved
if (a1 >= 0 && a1 <= 3)
{
cout << "(Acknowledgement " << arr1[a1] << " & all after this lost)\n";
sw = arr1[a1];
}
else
sw = (sw + fr_send_at_instance) % m;
}
else
{
f1 = rand() % fr_send_at_instance;
// f1 gives index of the frame being lost
for (int i = 0 ; i < f1 ; i++)
{
if (rw == arr1[i])
{
cout << " RECIEVER : Frame " << arr1[i] << " recieved correctly\n";
rw = (rw + 1) % m;
}
else
cout << " RECIEVER : Duplicate frame " << arr1[i] << " discarded\n";
}
int ld = rand() % 2;
// ld == 0 frame damaged
// else frame lost
if (ld == 0)
cout << " RECIEVER : Frame " << arr1[f1] << " damaged\n";
else
cout << " (Frame " << arr1[f1] << " lost)\n";
for (i = f1 + 1 ; i < fr_send_at_instance ; i++)
cout << " RECIEVER : Frame " << arr1[i] << " discarded\n";
cout << " (SENDER TIMEOUTS --> RESEND THE FRAME)\n";
sw = arr1[f1];
}
cout << "Want to continue...";
cin >> ch;
if (ch == 'y')
sender(m);
else
exit(0);
}
void main()
{
clrscr();
gobkn gb;
gb.input();
getch();
} |
Output
Enter the no of bits for the sequence no 4
SENDER : Frame 0 is sent
SENDER : Frame 1 is sent
SENDER : Frame 2 is sent
SENDER : Frame 3 is sent
SENDER : Frame 4 is sent
SENDER : Frame 5 is sent
SENDER : Frame 6 is sent
SENDER : Frame 7 is sent
RECIEVER : Frame 0 recieved correctly
RECIEVER : Frame 1 recieved correctly
RECIEVER : Frame 2 recieved correctly
RECIEVER : Frame 3 recieved correctly
RECIEVER : Frame 4 recieved correctly
RECIEVER : Frame 5 recieved correctly
RECIEVER : Frame 6 recieved correctly
RECIEVER : Frame 7 recieved correctly
Want to continue...n
