What is the Transport Layer? - Definition from Techopedia
`
`Page 1 of 3
`
`ALERT [WEBINAR] How to Optimize Use of the Hybrid Cloud
`(https://www.techopedia.com/reg/how-to-optimize-use-of-the-hybrid-cloud/33180?
`utm_source=house&utm_medium=termhello&utm_campaign=turbo)
`
`Transport Layer
`
`Definition - What does Transport Layer mean?
`
`The transport layer is the layer in the open system interconnection (OSI) model
`responsible for end-to-end communication over a network. It provides logical
`communication between application processes running on different hosts within a
`layered architecture of protocols and other network components.
`
`The transport layer is also responsible for the management of error correction,
`providing quality and reliability to the end user. This layer enables the host to send
`and receive error corrected data, packets or messages over a network and is the
`network component that allows multiplexing.
`
`In the OSI model, the transport layer is the fourth layer of this network structure.
`
`[WEBINAR] How to Optimize Use of the Hybrid Cloud
`(https://www.techopedia.com/reg/how-to-optimize-use-of-the-hybrid-cloud/33180?
`utm_source=house&utm_medium=termhello&utm_campaign=turbo)
`
`Techopedia explains Transport Layer
`
`Transport layers work transparently within the layers above to deliver and receive
`data without errors. The send side breaks application messages into segments and
`passes them on to the network layer. The receiving side then reassembles segments
`into messages and passes them to the application layer.
`
`The transport layer can provide some or all of the following services:
`
`• Connection-Oriented Communication: Devices at the end-points of a network
`communication establish a handshake protocol to ensure a connection is robust
`before data is exchanged. The weakness of this method is that for each
`delivered message, there is a requirement for an acknowledgment, adding
`considerable network load compared to self-error-correcting packets. The
`repeated requests cause significant slowdown of network speed when defective
`byte streams or datagrams are sent.
`
`https://www.techopedia.com/definition/9760/transport-layer
`
`2/21/2018
`
`Alacritech, Ex. 2044 Page 1
`
`

`

`What is the Transport Layer? - Definition from Techopedia
`
`Page 2 of 3
`
`• Same Order Delivery: Ensures that packets are always delivered in strict
`sequence. Although the network layer is responsible, the transport layer can fix
`any discrepancies in sequence caused by packet drops or device interruption.
`• Data Integrity: Using checksums, the data integrity across all the delivery layers
`can be ensured. These checksums guarantee that the data transmitted is the
`same as the data received through repeated attempts made by other layers to
`have missing data resent.
`• Flow Control: Devices at each end of a network connection often have no way
`of knowing each other's capabilities in terms of data throughput and can
`therefore send data faster than the receiving device is able to buffer or process
`it. In these cases, buffer overruns can cause complete communication
`breakdowns. Conversely, if the receiving device is not receiving data fast
`enough, this causes a buffer underrun, which may well cause an unnecessary
`reduction in network performance.
`• Traffic Control: Digital communications networks are subject to bandwidth and
`processing speed restrictions, which can mean a huge amount of potential for
`data congestion on the network. This network congestion can affect almost
`every part of a network. The transport layer can identify the symptoms of
`overloaded nodes and reduced flow rates.
`• Multiplexing: The transmission of multiple packet streams from unrelated
`applications or other sources (multiplexing) across a network requires some
`very dedicated control mechanisms, which are found in the transport layer. This
`multiplexing allows the use of simultaneous applications over a network such as
`when different internet browsers are opened on the same computer. In the OSI
`model, multiplexing is handled in the service layer.
`• Byte orientation: Some applications prefer to receive byte streams instead of
`packets; the transport layer allows for the transmission of byte-oriented data
`streams if required.
`
`https://www.techopedia.com/definition/9760/transport-layer
`
`2/21/2018
`
`Alacritech, Ex. 2044 Page 2
`
`

`

`What is the Transport Layer? - Definition from Techopedia
`
`Page 3 of 3
`
`Featured Q&A
`
`More of your questions answered by our Experts (/experts)
`
`https://www.techopedia.com/definition/9760/transport-layer
`
`2/21/2018
`
`Alacritech, Ex. 2044 Page 3
`
`