transport layer

Definition of transport layer in The Network Encyclopedia.

What is Transport Layer?

Transport layer is the Layer 4 of the Open Systems Interconnection (OSI) reference model. The transport layer is responsible for providing reliable transport services to the upper-layer protocols. These services include the following:

  • Flow control to ensure that the transmitting device does not send more data than the receiving device can handle
  • Packet sequencing for segmentation of data packets and remote reassembly
  • Error handling and acknowledgments to ensure that data is retransmitted when required
  • Multiplexing for combining data from several sources for transmission over one data path
  • Virtual circuits for establishing sessions between communicating stations

The Transmission Control Protocol (TCP) of the TCP/IP protocol suite resides at the transport layer.