UDP-User Datagram Protocol
It is a connectionless transport layer protocol,which belongs to the Internet protocol family. Basically UDP acts as an interface between the IP(Internet Protocol) and Upper layer processes.UDP protocol ports distinguish multiple applications running on a single device from one another.
TCP adds reliability,flow control and error recovery functions to the IP.But UDP adds no reliability,flow control and error recovery functions to the IP.The header of the UDP contain fewer bytes and it consume less network overhead,when compared to TCP.
UDP is very useful in situations where the reliability mechanisms of teh TCP are not necessary.
UDP acts as a transport protocol for several well-known application layer protocols,which includes Network File System(NFS),Simple Network Management Protocol(SNMP),Domain Name System(DNS) and Trivial File Transfer Protocol(TFTP).
The UDP packet format contains 4 fields,such as source and destination ports,length and checksum fields.
Source Port:
It indicates the port of the sending process.It is the port to which repiles should be addressed.
Destination Port:
It specifies the port of the destination process on the destination host.
Length:
It is the length of this user datagram including the header.
Checksum:
It is an optional 16 bit one's complement of the one's complement sum of a pseudo-IP header.