UDP

User Datagram Protocol-UDP

• Introduction
• UDP Client Server IPv4
• UDP Client Server IPv6
• UDP Client Server Dual-Stack
• UDP Client Server IPv6 convered IPv4

Introduction

UDP one of the simplest and lightweight Transport Layer Protocol that fall under un-realiable and connection-less protocol categories. 

UDP is primarily used where  Time (how much less Time of delivery) is more important than packet drop, best for time-sensitive applications. RFC-768 is the standard document for UDP. 

Lets discussed some of the important features of UDP.

• It does not perform any handshake to establish connection between two peers; because it is connection-less protocol.
• IT simply adds a header to data before sending. Header as follow:

         

UDP Header Format

1. Source Port: 16-Bits field used to identify source port, usually used to receive response.
2. Destination Port: 16-Bits field used to represent destination port
3. Length: Length in bytes (Data + Header)
4. Checksum: It is 16 bit 1's complement of [ 1's complement sum of Pseudo Header of IP Header], [UDP Header] [Data (with padding with Zero if required to make multiple of 16 bits/2-bytes ]

• As UDP is Transport Layer Protocol that is why IP address (Network Layer Protocol) is not to be taken care here in this Header.
• Packets(Datagram) may arrive in different order, it is not necessary that packets(Datagram) shall arrive in the order they are sent.
• Some of the applications that use UDP protocol are Domain Name System (DNS), Network Time Protocol (NTP), Voice Over IP (VoIP Ususally) and DHCP.
• Some of the Real-Time application that are best example of UDP protocols are such as online gaming, voice or video conferencing and streaming media.
• As it is a connection-less protocol therefore can be best use for Broadcast and Multicast operations.