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  • Essay / Introduction to the transport layer of the OSI model

    IntroductionThe transport layer is the 4th layer of the OSI model. The transport layer provides a peer-to-peer and end-to-end connection between two processes on remote hosts. The transport layer provides reliable connection-oriented and connectionless solutions depending on the application. The transport layer takes data from the application layer, then divides it into smaller segments, numbers each byte, and passes it to the network layer for delivery. The most common transport layer protocols are Transmission Control Protocol (TCP) and connectionless UDP User Datagram Protocol (UDP). Both protocols are connection oriented. Other transport layer protocols are: Say no to plagiarism. Get a tailor-made essay on “Why violent video games should not be banned”?Get the original essayATP: AppleTalk Transaction ProtocolCUDP: Cyclic UDPDCCP: Datagram Congestion Control ProtocolFCP: Fiber Channel ProtocolIL: IL ProtocolMPTCP: Multipath TCPRDP: Reliable Data ProtocolRUDP : Reliable User Datagram ProtocolSCTP: Stream Control Transmission ProtocolSPX: Sequenced Packet ExchangeSST, Structured Stream TransportTCP: Transmission Control ProtocolµTP: Micro Transport ProtocolAny host can have multiple applications that communicate over the network. Each of these applications will communicate with one or more applications on remote hosts. It is the responsibility of the Transport layer to maintain the multiple communication flows between these applications. Topic Analysis As each application creates a stream of data to send to a remote application, this data must be prepared for sending over the medium in manageable chunks. Transport layer protocols describe the services that segment this Application layer data. This includes the required encapsulation on each data element. Each application data element requires headers to be added at the Transport layer to indicate which communication it is associated with. At the receiving host, each piece of data can be directed to the appropriate application. Additionally, these individual data elements must also be reconstructed into a complete data flow useful to the Application layer. Transport layer protocols describe how Transport layer header information is used to reassemble streaming data elements for transmission to the Application layer. In order to deliver data streams to the appropriate applications, the Transport layer must identify the target application. To do this, the Transport layer assigns an identifier to an application. TCP/IP protocols call this identifier a port number. Each software process that needs to access the network is assigned a unique port number on that host. This port number is used in the transport layer header to indicate which application this data is associated with. The Transport layer is the link between the Application layer and the lower layer which are responsible for network transmission. This layer accepts data from different conversations and passes it to lower layers in manageable chunks that can optionally be multiplexed across the media. Applications do not need to know the operational details of the network in use. Applications generate data that is sent from one application to another, regardless of the type of destination host, the type of media the data must travel on, the path the data takes, congestion on a link, or the size of the network. Additionally, lower layers are unaware that multiple applications are sending data over the network. Their responsibility is to transmit.