What is User Datagram Protocol (UDP). Operation of User Datagram Protocol. And uses of User Datagram Protocol.

User Datagram Ptotocol

The user datagram protocol is called a connectionless, unreliable trandpotrprotocol. It does not add anything to the services of IP except to provide process- to- process communication. Also it performs very limited error checking.

UDP packets called user datagram have a fixed size header of 8 bytes.

Souce code number:

This is the port number used by the process running on the source host. It is 16 bits long, which means that the port number can range from 0- 65,535.

Destination port number:

This is the port number used by the process used by the destination host. It is slso 16 but long.

Length:

This is a 16 bit field. That defines the total length oftheo source datagram, header and data.

Checksum:

This field us used to detect errors over the entire user data.

UDP Operations:

Connectionless services:

UDP provides a connectionless service, which means each user datagram send by UDP is an independent datagram. The user datagram are not numbered. Since there is no connection establishment and no connection establishment. So each user datagram can travel on a different path. UDP can not sent a string of data to UDP. Instead each request must be small enough to feed in to ine user datagram.

Flow and error control:

There is no flow control and hence no window mechanism. The receiver may overflow with incoming massages. 

There is no error control mechanism in UDP except for the checksum.

It means that the sender does not know if a massage has been last or duplicated. When the receiver detects an error through the checksum, the user datagram is silently discard. 

Encapsulation and decapsulation:

To send a massage fron ine process to another the UDP protocol encapsulates massages in a IP datagram.

Queuing:

Queues are associated with ports. When a process starts it requires a port number from the operation system. Then incomiand outgoing queues associated with each process is created.

Uses of UDP:

1.  UDP is suitable for a process that requires simple- request- response communication.( It is not usually used for a process such as FTP that needs to send bulk data)
2.  UDP us suitable for a process with internal flow and error control mechanism. Ex- TFTP ( trivial file transfer protocol)
3. UDP is a suitable transport protocol for multicasting.
4. UDP is used for management process such as SNMP.
5.  UDP is used for some root updating protocols, such as routine information protocol.