The Application layer has the function of providing interface between software applications and network for interpreting the requests and requirements for applications. “This top layer defines the language and syntax that programs use to communicate with other programs. ” (“OSI model, “2009, p. 01). The Presentation layer allows hosts and applications to utilize a common language. It also performs encryption, formatting, and compression.
There's a specialist from your university waiting to help you with that essay.
Tell us what you need to have done now!
order now
“When the data are transmitted between different types of computer systems, the presentation layer negotiates and manages the way data is represented and encoded. (OSI model, “2009, p. 01). The Session layer establishes, maintains, and terminates user connections. The Transport layer ensures the precise delivery of data through flow control, segmentation and reassembly, error correction, and acknowledgement. “The lower layers may drop packets, but the transport layer performs a sequence check on the data and ensures that if a 12MB file is sent, the full 12MB is received. ” (OSI model, “2009, p. 01). The Network layer establishes network connections and translates network addresses into their physical counterparts and determines routing.
In order to provide services to the Data Link layer, it must convert the logical network address into physical machine addresses, and vice versa on the receiving computer. The Data Link layer packages data in frames appropriate to network transmission method. “The data link is responsible for node validity and integrity of the transmission. ” (OSI model, “2009, p. 01). The bottom layer is the Physical layer, which manages signaling to and from physical network connections. It is responsible for sending bits across the network media.
Hardware and Protocols/Standards are divided under the appropriate layers in the OSI model. Gateways, Proxy servers, Application switches and Content Filtering Firewalls fall under four different layers. They are Application, Presentation, Session and Transport. Routers, Layer 3 switches and Firewalls fall under the Network layer. Bridges, Switches and Wireless access points fall under the Data Link layer. Hubs and Repeaters fall under the Physical layer. NICs, Modems, Cable modems and DSL modems fall under the Data Link and Physical layer.
Some common applications in the Application layer possess Internet Message Access Protocol, File Transfer Protocol and Simple Network Management Protocol. Common gateways in the Presentation layer include; Systems Network Architecture: Gateways enable PCs to communicate with mainframe computers and E-mail gateways enable data to be transmitted between different e-mail applications. The Session layer has name lookup and security functions. It also establishes a point where a message starts and a message ends.
The Transport layer is where the TCP and UDP protocols are initiated. They are the common transport protocols for this layer. The Network layer possesses flow control, error detection and error recovery. The Data link layer is responsible for the managing error messaging specific to the delivery of packets. Finally the physical layer is responsible for the physical topologies of the network. The functions of hardware in the OSI model support similar to the functions of the model layers.
