TCP, UDP & Ports
Compare TCP and UDP and identify the role of ports, reliability and flow control.
Multiplexing applications
Transport ports let one host run multiple networked processes. A connection is commonly identified by source IP, source port, destination IP, destination port and transport protocol. A client usually chooses a temporary source port; a server listens on a known destination port.
TCP and UDP both carry ports, but neither port number proves that a particular application is running.
Different transport promises
TCP provides a reliable ordered byte stream with connection setup, acknowledgments, retransmission, flow control and congestion control. UDP sends independent datagrams without built-in delivery, ordering or congestion guarantees. An application using UDP may implement extra behavior itself.
TCP's three-way handshake synchronizes a connection before ordinary data transfer. A UDP datagram has no equivalent TCP handshake.
Check your understanding
Which transport supplies an ordered byte stream?