The transport layer of the Open Systems Interconnection (OSI) reference model, where such protocols as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) operate. See OSI, TCP and UDP.
Transport The purpose of the Transport layer is to provide transparent transfer of data between end users, thus relieving the upper layers from any concern with providing reliable and cost-effective data transfer. The transport layer controls the reliability of a given link. Some protocols are stateful and connection oriented. This means that the session layer can keep track of the packets and retransmit those that fail. NetBEUI Q.931 TCP UDP RTP SCTP