What feature distinguishes TCP from UDP?

The distinguishing feature of TCP (Transmission Control Protocol) is its reliability in delivery. TCP is a connection-oriented protocol, which means that it establishes a connection between the sender and receiver before data transmission occurs. This connection ensures that all packets of data are delivered in order and without errors. If any packets are lost or arrive out of sequence, TCP has mechanisms in place to retransmit the missing packets and reassemble the data correctly, which ensures reliable communication.

On the other hand, UDP (User Datagram Protocol) is a connection-less protocol and does not include these reliability features. While UDP is often faster due to its lack of overhead for connection management and error-checking, it sacrifices the guaranteed delivery and ordering that TCP provides. Therefore, the reliability aspect is a key distinguishing factor between TCP and UDP.