The transport layer is responsible for end-to-end delivery of data from the source host to destination host. At this point, the data will be segmented into smaller units called segments or sometime datagrams. These segments are of a size suitable for transmission over the network. The transport layer ensures the reliability and the order of the data during delivery.
Transport layer protocol
Transmission Control Protocol (TCP)
TCP is a connection-oriented protocol that ensures reliable and ordered delivery of data using sequence numbers. TCP accepts data from a data stream, divides it into chunks, and adds a TCP header creating a TCP segment. (the segment will later been encapsulated into an IP datagram)
TCP ports
TCP ports acts as endpoints for communication within a device, IP address identifies the device in the network, whereas ports specifies which application or service on a device should receive the incoming data. Think of IP address as the building number and port as the room number within the building. (more details on TCP Port)
A TCP segment contains segment header and data section, inside the segment header there are: source port (16bits), destination port (16bits), sequence number (32bits), acknowledgment number (32bits), and some other trivial information.
User Datagram Protocol (UDP)
UDP is another protocol which does not require IP to communicate with another computer. IP is requested by the TCP only. UDP offers no guarantees of delivery and the order of data unless embed a higher level protocol.
Back to parent node: Internet Protocol Suite
Computer_networksINFO1112IPTransport_layerTransmission_Control_Protocol_TCPUser_Datagram_Protocol_UDP