Stop And Wait Protocol Using Socket Programming In C++
importjava.net.*;
Socketsender;
ObjectInputStreamin;
A list of video related to various topic regarding Socket Programming in C programming language. It consists of TCP and UDP client-server program. Stop and Wait Protocol Implemented in UDP C. A Protocol Using Go-Back-N Computer Network Computer Engineering MCA Go-Back-N protocol, also called Go-Back-N Automatic Repeat reQuest, is a data link layer protocol that uses a sliding window method for reliable and sequential delivery of data frames. Before you start learning socket programming in c, you should basic knowledge of IP address, TCP, UDP. A TCP/IP is a connection-oriented communication, send the data packets over the network and ensures that data is delivered to the correct destination.
intn,i=0,sequence=0;
public voidrun(){
BufferedReaderbr=new BufferedReader(new InputStreamReader(System.in));
sender= new Socket('localhost',2004);
out=newObjectOutputStream(sender.getOutputStream());
in=newObjectInputStream(sender.getInputStream());
System.out.println('reciver > '+str);
packet=br.readLine();
do{
if(i<n){
msg=msg.concat(packet.substring(i,i+1));
elseif(in){
}
sequence=(sequence0)?1:0;
System.out.println('datasent>'+msg);
System.out.println('waitingfor ack...nn');
i++;
System.out.println('receiver > '+' packet recievednn');
else{
System.out.println('Timeout resending data..nn');
}
}while(i<n+1);
}catch(Exceptione){}
try{
out.close();
}
}
publicstatic void main(String args[]){
s.run();
}
//RECEIVER PROGRAM
import java.io.*;
public class Reciever{
Socketconnection=null;
ObjectInputStreamin;
inti=0,sequence=0;
public voidrun(){
Stop And Wait Protocol Using Socket Programming In C#
BufferedReaderbr=new BufferedReader(new InputStreamReader(System.in));
System.out.println('waitingfor connection..');
sequence=0;
out=newObjectOutputStream(connection.getOutputStream());
in=newObjectInputStream(connection.getInputStream());
do{
packet=(String)in.readObject();
if(Integer.valueOf(packet.substring(0,1))sequence){
sequence=(sequence0)?1:0;
}
{
System.out.println('nnreceiver >'+packet +' duplicate data');
if(i<3){
}
out.writeObject(String.valueOf((sequence+1)%2));
}
catch(Exceptione){}
System.out.println('Datarecived='+data);
}
finally{
in.close();
reciever.close();
catch(Exceptione){}
}
Recievers=new Reciever();
s.run();
}
}OUTPUT:
Waiting for Connection..
Enter the data to send..
data sent>0m
receiver > packet recieved
waiting for ack...
data sent>0n
receiver > packet recieved
waiting for ack...
data sent>1a
receiver > packet recieved
waiting for ack...
data sent>1e
receiver > packet recieved
waiting for connection..
receiver >0m
receiver >0n
receiver >1a duplicate data
receiver >1e
waiting for connection..
1.0 Datagram sockets
There are two major types of network sockets, viz. Stream sockets (SOCK_STREAM) and Datagram sockets (SOCK_DGRAM). The socket type defines the semantics of communication between this socket and its remote counterpart. Stream sockets provide full-duplex reliable sequenced data streams. Datagram sockets support connection-less unreliable messages between the source and destination sockets. Datagram sockets use the User Datagram Protocol (UDP) for communication over the network.
2.0 User Datagram Protocol
Stop And Wait Protocol Using Socket Programming In Cpp
User Datagram Protocol (UDP) is a fundamental network protocol for transmission of messages referred to as datagrams. UDP has minimal overheads. Idm terbaru dan cracknya. There are no acknowledgments and, therefore, delivery is not guaranteed. Datagrams may be delivered out of sequence. However, packets have a checksum and data integrity of a packet is guaranteed. Because of low overheads, UDP is fast and suitable in many situations, particularly in real time systems. For example, if some periodic data is being transmitted, a few lost packets might not matter because similar relevant and more current data is coming next at short intervals.
3.0 System calls
Stop And Wait Protocol Using Socket Programming In Cmd
3.1 sendto
The sendto system call is used to send a message to a remote unconnected socket. It can be used for sending a message to a connected socket also, provided the last two parameters are NULL and 0 respectively. The first parameter, sockfd is the file descriptor of the sending socket. The message is at buf and its length is the third parameter, len. The flags would mostly be zero for datagram sockets. The last two parameters are for the destination socket. dest_addr is the destination socket address and addrlen is its length.
sendto returns the number of bytes sent on success. In case of failure, -1 is returned and errno is set accordingly.
3.2 recvfrom
The recvfrom system call is for receiving a message from the socket identified by the file descriptor, sockfd. buf is the buffer in which the received message would be returned and len is the length of the buffer. flags are mostly 0 for datagram sockets. recvfrom blocks if there is no message. If non-blocking operation is required, you can specify MSG_DONTWAIT as flags. So, if MSG_DONTWAIT is specified as flags, and there is no message, recvfrom fails with the error EAGAIN or EWOULDBLOCK. The last two parameters are for the source socket. src_addr is a buffer, big enough to receive the socket address of the source socket. The system returns the source socket address in the src_addr buffer. addrlen is a value-result argument. Before the call, addrlen is set to the length of the buffer src_addr. After the call, the system returns the length of the source socket address written in src_addr in addrlen. If the caller does not need the source socket address, the last two parameters can be set to NULL and the system ignores them.
recvfrom returns the number of bytes received on success. In case of error, -1 is returned and errno is set to indicate the error.
For description of other network socket programming system calls and functions, please refer to Network Socket Programming using TCP in C.
4.0 A Client-server example
As an example we have a weather server, which keeps track of weather of cities around the world. To be fair, our weather server is rather simplistic. It only keeps track of temperatures of cities, as of now. There are clients, that report the temperature of cities to the server. Our server records the given temperature of a city. A client may also query the temperature of a city and our server graciously responds with the last recorded temperature value for that city. The client and server communicate using the UDP.
The server keeps a binary tree with record of each city. When a message to store temperature for a city comes, the server checks if there is already a record for that city. If it exists, the server updates the temperature for that city. If there is no record, the server creates a new record for that city. If a client queries the temperature for a city, the server looks for the record for that city. If it finds the record, it responds with the temperature for that city to the client. If there is no record, the server tells the client that it does not have temperature for that city. Note that the server keeps the temperature as double precision floating point in its data structure but text format is used for the same in messages between the clients and the server. There might be differences in floating point representation in different computers and we avoid the problem by transmitting the temperature in text format.
4.2 The client program
A client has two threads. One thread is for accepting user commands and sending relevant messages to the server. The second thread waits for messages from the server. As soon as a message comes, it prints it on the output terminal.
We can compile and execute the server and client programs.