URGENT Project

[sharma]

I have to submit my project for evaluation this week.

Project Statement : In an organization, a project manager assigns different modules of a project to members. The module codes need to be sent through a network channel that is susceptible to errors, by a team leader to integrate it. Team leader has sufficient space to store the modules but within limited time, he has to submit all modules in order to the project manager. Implement the concept so that the project manager gets all the modules correctly.

>>It is a project to implement Selective Repeat ARQ protocol in Computer Networks based on the Data Link Layer. I need to provide a user interface to show the easiest implementation of sending and recieving frames using this protocol in C++.

[ajh32]

(1) How long (so far) have you had this assignment to do?

(2) Have you written any code yet, or written some type of design for your program?

(3) What type of program is it? GUI or terminal?

(4) Which OS is it to run on?

[sharma]

1. I had this assignment for a week but due to some preoccupation i am not able to do it.

2. I have the code for Go Back N ARQ which is similar to this algo but a few minor differences such as the size of sender and reciever window in this should be same and each frame has its own timer.

3. I need to run it on Windows and using C++ only.

Im pasting the code for Go Back N ARQ here, but theres a problem with this one too. :

#include<iostream.h>
#include<conio.h>
#include<math.h>

class sender
{
public :
int size,sf,sn,t,a[500],w,ff;
sender(){}//default constructor
sender(int x,int aa)//parameterised constructor
{ 
           ff=aa;  //ff and aa = total no of frames 
size=pow(2,x)-1;//size of sliding window
sn=0;//next frame to sent
sf=0;//first outstanding frame
w=0;//count of frames 
t=5;//timer (decremented by 1 after a frame in sent)
for(int i=0;i<aa;i=i+size+1)//to assign sequence no to frames
{ 
for(int j=0;j<=size;j++)
{
if(i+j < aa)

a[i+j]=j;

}

}

} 

void reqstsend()//to send frames

{

if(w<ff)//check whether the no. of frame sent is less than total no of frames

{

if(t<=0 )//check for time out
{
cout<<endl<<"timer out"<<endl;

timeout();

}

else if((sn-sf)>=size || sf==sn+1 )

{

cout<<endl<<"window is full"<<endl;

t--;

}

else if(sn == size)//special case when sn==size sn should be =0

{

cout<<endl<<"frame F"<<sn<<" sent..."<<endl;

sn=0;

t--;

w++;

}

else//normal sending

{

cout<<endl<<"frame F"<<sn<<" sent..."<<endl;

sn++;

t--;

w++;

}

}

else

cout<<endl<<" ***all frames sent***"<<endl;

}


 

void arivack(int y)//recieving acknowledgement

{

sf=y;

t=5;

}

void timeout()

{

sn=sf;

t=5;

w=w-5;

}

void sdisplay()//displaying frames initially

{

cout<<endl<<"frames :- ";

for(int i=0;i<ff;i++)

cout<<" "<<a[i]<<" ";

cout<<endl<<endl<<"sn = "<<sn<<endl<<"sf = "<<sf<<endl;

}

};//class sender ends
 
class reciever

{

public :

int rn,b[500],c;

sender *s;

reciever(sender *y,int q)

{

rn=0;//next expected frame

c=0;//coounter

for(int i=0;i<q;i++)

b[i]=0;

s=y;

}

void arivnot(int x)

{

if(rn == x)//recieve in order

{

if(rn != s->size)//recieving frames

{

b[c]=rn;

c++;

rn++;

}

else//special case when rn =size, then rn should be =0

{

b[c]=rn;

c++;

rn=0;

}

}

}


 

void sendack(int z)

{

cout<<endl<<"acknowledgement A"<<z<<" sent"<<endl;

s->arivack(z);

}


 

void rdisplay()

{

cout<<endl<<"frames recieved :- ";

for(int i=0;i<c;i++)

cout<<" "<<b[i]<<" ";

cout<<endl<<"rn = "<<rn<<endl;

}

};//class reciever end


int main()

{

int m,x=3,h,y;

cout<<endl<<"enter the value of m  i.e  no of bits allowed for sequence no. :--> ";

cin>>m;

cout<<"size of sliding window ="<<pow(2,m)-1<<endl;

cout<<"enter the total no of frames you want to send "<<endl;

cin>> h;

sender pqr(m,h),*g=&pqr;

reciever rec(g,h),*r=&rec;

while(x != 0)

{
            
 int counter =0;

if(counter==0)

{
             cout<<endl<<"1 --> go to sender"<<endl

             <<"0 --> exit"<<endl

             <<"enter code :--> ";

cin>>x;
counter++;
}


else

{
             cout<<endl<<"1 --> go to sender"<<endl

             <<"2 --> go to reciever"<<endl

             <<"0 --> exit"<<endl

             <<"enter code :--> ";

cin>>x;

}

switch(x)

{

case 1 : while(y != 3)

             {

             pqr.sdisplay();

             cout<<endl<<"1 --> send frame"<<endl

                         <<"2 --> send frame (lost or incorrect)"<<endl

                         <<"3 --> go back"<<endl

                         <<" :--> ";

             cin>>y;

             switch(y)

             {

             case 1 : pqr.reqstsend();

                         if(pqr.sn == 0)

                         r->arivnot(pqr.size);

else

                         r->arivnot(pqr.sn-1);

                         break;

             case 2 : pqr.reqstsend();

                         break;

             case 3 : break;

             default : cout<<endl<<"!!! error in code !!!"<<endl;

                         break;

             }

             }

             y=0;

             break;

case 2 : while(y != 2)

             {

             r->rdisplay();

             cout<<endl<<"1 --> send acknowledgement"<<endl

                         <<"2 --> go back"<<endl

                         <<" :--> ";

             cin>>y;


 

             switch(y)

             {

             case 1 : r->sendack(rec.rn);

                         break;

             case 2 : break;

             default : cout<<endl<<"!!! error in code !!!"<<endl;

                         break;

             }

             };

             y=0;

             break;

case 0 : break;

default : cout<<endl<<"!!! error in code !!!"<<endl;

                break;


 

}


}

getch();

}