Transport layer

TCP is the more complex protocol, due to its stateful design incorporating reliable transmission and data stream services.

Together, TCP and UDP comprise essentially all traffic on the Internet and are the only protocols implemented in every major operating system.

The services may include the following features:[4] The transport layer is responsible for delivering data to the appropriate application process on the host computers.

Some transport layer protocols, for example TCP, but not UDP, support virtual circuits, i.e. provide connection-oriented communication over an underlying packet-oriented datagram network.

UDP is a very simple protocol and does not provide virtual circuits, nor reliable communication, delegating these functions to the application program.

UDP typically gives higher throughput and shorter latency and is therefore often used for real-time multimedia communication where packet loss occasionally can be accepted, for example IP-TV and IP-telephony, and for online computer games.

All OSI connection-mode protocol classes provide expedited data and preservation of record boundaries.