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By means of an error detection code, such as a checksum, the transport protocol may check that the data is not corrupted, and verify correct receipt by sending an ACK or NACK message to the sender. Reliability: Packets may be lost during transport due to network congestion and errors.This is usually done through the use of segment numbering, with the receiver passing them to the application in order. Same order delivery: The network layer doesn't generally guarantee that packets of data will arrive in the same order that they were sent, but often this is a desirable feature.Connection-oriented communication: It is normally easier for an application to interpret a connection as a data stream rather than having to deal with the underlying connection-less models, such as the datagram model of the User Datagram Protocol (UDP) and of the Internet Protocol (IP).The services may include the following features: Transport layer services are conveyed to an application via a programming interface to the transport layer protocols. 3.2 Comparison of OSI transport protocols.3.1 Comparison of Internet transport layer protocols.Additional transport layer protocols that have been defined and implemented include the Datagram Congestion Control Protocol (DCCP) and the Stream Control Transmission Protocol (SCTP). Together, TCP and UDP comprise essentially all traffic on the Internet and are the only protocols implemented in every major operating system. TCP is the more complex protocol, due to its stateful design incorporating reliable transmission and data stream services. It is used for connection-oriented transmissions, whereas the connectionless User Datagram Protocol (UDP) is used for simpler messaging transmissions. The best-known transport protocol of the Internet protocol suite is the Transmission Control Protocol (TCP). In the OSI model the transport layer is often referred to as Layer 4, or L4, while numbered layers are not used in TCP/IP. The protocols in use today in this layer for the Internet all originated in the development of TCP/IP. The details of implementation and semantics of the transport layer of the Internet protocol suite, which is the foundation of the Internet, and the OSI model of general networking are different. : §1.1.3 It provides services such as connection-oriented communication, reliability, flow control, and multiplexing. The protocols of this layer provide end-to-end communication services for applications. In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet protocol suite and the OSI model.