simple-datagram

Datagram is the unit of data exchanged between a pair of internet modules (includes the internet header). This program is built for enhancing the understanding of datagram based on RFC 791.

This repository contains a simple example of how to create and send datagrams using the UDP protocol in Go. The project includes two parts: a UDP server and a UDP client that sends datagrams to the server.

Overview

A datagram is a unit of data exchanged between two devices over a network using a connectionless protocol such as UDP (User Datagram Protocol). Unlike TCP, which establishes a connection before data transfer, UDP simply sends data packets (datagrams) without requiring a connection. This makes UDP faster but less reliable, as there is no guarantee of packet delivery.

This project demonstrates how to:

• Create a UDP server that listens for incoming datagrams.
• Create a UDP clients that sends datagrams to the server.

Project Structure

• server.go: The UDP server code that listens for incoming datagrams on a specified port.
• client.go: The UDP client code that sends a datagram message to the server.

How It Works

1. The server listens on port 8080 for incoming datagrams.
2. The client sends a datagram message ("Hello, this is a datagram!") to the server.
3. The server receives and prints the message along with the sender's address.

Running Example

Prerequisites

• Go installed on your machine.

Steps

1. Run The Server:
   • Open a terminal and navigate to the directory containing the server.go file.
   • Start the server using the following command:

   go run server.go
   

   • The server will start listening on localhost:8080 for incoming UDP datagrams.
2. Run The Client:
   • Open another terminal and navigate to the directory containing the client.go file:
   • Send a datagram message to the server using the following command:

   go run client.go
   

3. Output:
   • In the terminal server, you will see output like this when it receives a datagram:

   Listening on localhost:8080
   Received Hello, this is a datagram from 127.0.0.1:xxxxx
   

   • The client will display:

   Sent message: Hello, this is a datagram!
   

Code Explanation

Server Code (server.go)

The server is implemented using Go's net package:

• net.ResolveUDPaddr: Resolves the address for UDP communication.
• net.ListenUDP: Binds the UDP address and starts listening for incoming datagrams.
• conn.ReadFromUDP: Reads the incoming datagram into a buffer.

Client Code (client.go)

The client sends a datagram using:

• net.ResolveUDPaddr: Resolves the server's UDP address.
• net.DialUDP: Creates a UDP connection to the server.
• conn.Write: Sends a datagram message over the UDP connection.

Notes

• UDP is a connectionless protocol, meaning there is no guarantee that the datagram will reach the destination. It's faster but less reliable compared to TCP.
• This example uses localhost communication, but you can modify the IP and port to test on different machines over a network.

License

This project is open-source and licensed under the MIT License.