UDP - Client And Server Example Programs In Python

UDP Overview:

UDP is the abbreviation of User Datagram Protocol. UDP makes use of Internet Protocol of the TCP/IP suit. In communications using UDP, a client program sends a message packet to a destination server wherein the destination server also runs on UDP.

Properties of UDP:

  • The UDP does not provide guaranteed delivery of message packets. If for some issue in a network if a packet is lost it could be lost forever.

 

  • Since there is no guaranty of assured delivery of messages UDP is an unreliable protocol.

 

  • The underlying mechanisms that implement UDP involve no connection-based communication. There is no streaming of data between a UDP server or and an UDP Client.

 

  • An UDP client can send "n" number of distinct packets to an UDP server and it could also receive "n" number of distinct packets as replies from the UDP server.

 

  • Since UDP is connectionless protocol the overhead involved in UDP is less compared to a connection based protocol like TCP.

 

Example: UDP Server using Python

import socket

 

localIP     = "127.0.0.1"

localPort   = 20001

bufferSize  = 1024

 

msgFromServer       = "Hello UDP Client"

bytesToSend         = str.encode(msgFromServer)

 

# Create a datagram socket

UDPServerSocket = socket.socket(family=socket.AF_INET, type=socket.SOCK_DGRAM)

 

# Bind to address and ip

UDPServerSocket.bind((localIP, localPort))

 

print("UDP server up and listening")

 

# Listen for incoming datagrams

while(True):

    bytesAddressPair = UDPServerSocket.recvfrom(bufferSize)

    message = bytesAddressPair[0]

    address = bytesAddressPair[1]

    clientMsg = "Message from Client:{}".format(message)
    clientIP  = "Client IP Address:{}".format(address)
    
    print(clientMsg)
    print(clientIP)

   

    # Sending a reply to client

    UDPServerSocket.sendto(bytesToSend, address)

Output:

UDP server up and listening

Message from Client:b"Hello UDP Server"

Client IP Address:("127.0.0.1", 51696)

 

 

Example: UDP Client using Python

 

import socket

 

msgFromClient       = "Hello UDP Server"

bytesToSend         = str.encode(msgFromClient)

serverAddressPort   = ("127.0.0.1", 20001)

bufferSize          = 1024

 

# Create a UDP socket at client side

UDPClientSocket = socket.socket(family=socket.AF_INET, type=socket.SOCK_DGRAM)

 

# Send to server using created UDP socket

UDPClientSocket.sendto(bytesToSend, serverAddressPort)

 

msgFromServer = UDPClientSocket.recvfrom(bufferSize)

 

msg = "Message from Server {}".format(msgFromServer[0])

print(msg)

 

 

  Output:

 

Message from Server b"Hello UDP Client"

 

 


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