• It is unreliable and connectionless transport-layer protocol that creates a process-to-process communication, which means it requires little overhead and offers fast delivery
• The UDP packet is called a User Datagram
• Has no flow and error control mechanism (only attempt to error control is checksum)
• Uses multiplexing and demultiplexing to handle outgoing and incoming user datagrams
• A UDP package can involve five components: a control-block table, a control-block module, input queues, an input module, and an output module
• It is fast compared to TCP

Services of UDP

1. Process-to-Process Communication

• Provides using socket addresses (IP addresses + port number)

2. Connectionless Service

• Each user datagram is an independent datagram

3. Flow Control

• No flow control (no window mechanism)

4. Error Control

• No error control except checksum

5. Congestion Control

• Since its connectionless protocol, it does not provide congestion control

6. Encapsulation and Decapsulation

• To send messages from one user to another user it encapsulates and decapsulates messages

7. Queuing

• Here queues are associated with ports

8. Multiplexing and Demultiplexing

• Used to handle several processes obtaining this service