What is the difference between TCP and UDP?

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are two main transport layer protocols in the OSI model.

Main differences:

• Reliability: TCP provides reliable data delivery by establishing a connection, confirming receipt of packets, and retransmitting lost packets. UDP does not guarantee delivery; packets may be lost.
• Connection: TCP is connection-oriented, while UDP is connectionless.
• Speed: UDP is faster because it does not spend time on connection setup and acknowledgments.
• Order: TCP guarantees the order of packet delivery, UDP does not.

Use cases:

• TCP is suitable for applications where reliability is important (HTTP, FTP, SMTP).
• UDP is used where speed is crucial and some loss is acceptable (video streaming, online gaming, DNS queries).