Research paper for Computer Networking PDF

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OSI MODEL LAYERS

Devices, Application, Protocols, and Services at Different OSI Layers

University of Maryland Glopal College CMIT 265 Computer Networking

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OSI MODEL LAYERS Devices, Application, Protocols, and Services at Different OSI Layers Introduction The Open Systems Interconnection (OSI) model is a collection of global standards that describes the underlying technological infrastructure used in delivering information between users within a network. The reference model was proposed in 1997 to facilitate data exchange by dividing the process into seven distinct layers [1]. The research on the physical, network, application, session, data, transport, and presentation layers of the OSI model is important to help

one understand the ways the system enhances interoperability between multiple communication systems [4]. For instance, the research would help provide insights on the protocols and devices used within each layer and the way they interact regardless of the type of technology and manufacturer [1]. Therefore, the study on the OSI model and the applications, devices, services, and protocols involved in each layer is important because it helps one understand its interoperability during communication. Devices, Application, Protocols, and Services at Different OSI Layers Physical Layer The layer is the first and lowest level in the Open System Interconnection (OSI) model and responsible for the placement of data into communication media, such as cables. The primary services at the physical layer include bit synchronization and bitrate control [2]. Bit synchronization entails use of a clock to control the sender and receiver data while bitrate control involves the monitoring of transmission rate. The physical layer involves network devices used in data transmission, including a repeater, hub, and cables. The devices facilitate the transmission of bits of data from one user to another. The primary protocols used in the layer are Bluetooth, Digital Subscriber Line (DSL),

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OSI MODEL LAYERS and Wi-Fi protocols. The protocols use various technologies, such the Wi-Fi’s IEEE 802.11, to facilitate data transfer between devices. Data Link The data link layer facilitates transfer of data between nodes. The primary services of the layer are flow and error control. The layer implements mechanisms to detect errors, such as loss of data frames, and limits them [3]. Besides, data link layer monitors the amount of data transmitted to enhance constant data rates for senders and receivers. Protocols used at the layer include the Address Resolution Protocol (ARP) and Point-toPoint Protocol (PPP). The ARP and PPP protocols help in relaying the network addresses to hardware and direct communication between routers respectively [2]. The primary devices for the layer include bridges and switches that facilitate connection between Local Area Networks (LANs) and computers. Network Layer The third layer of the Open System Interconnection (OSI) model provides the routing and logical addressing services in a communication network. The services facilitate data transfer between two hosts within multiple networks [3]. For instance, routing service implement routing protocols, such as the Internet Protocol and Internetwork Packet Exchange (IPX), to establish a

suitable channel to move data from a sender to a receiver. The devices used to enhance communication within the layer are the routers and switches. Routers help in redirecting packets of data between nodes in two networks while switches facilitate redirecting of data between two devices [3]. Therefore, the devices, protocols, and services of network layer are aimed at discovery of routes and redirection of data packets. Transport Layer

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OSI MODEL LAYERS The layer is responsible for transfer of segments of data between two nodes while exchanging services between the upper and lower layers. Furthermore, transport layer accomplishes error control by acknowledging successful data transfer and initiating retransmission during failed data transmission [3]. Service point addressing within the layer utilizes headers to specify and monitor address for accurate deliver of messages. Connection-oriented and connectionless services are the primary services within the transport layer. Connection oriented services involves three stages during data transfer. The establishment of connection, data transmission, and disconnection stages provides a secure and reliable service to share packets between groups. Connectionless service prioritizes communication speed by having one phase during communication. The transport layer uses the transmission control protocol to develop a guideline for establishing connections and exchanging data between multiple nodes. Session Layer The session layer helps computer networks to establish, maintain, and end connection sessions when devices are communicating. Other services provided by the layer include dialog control and synchronization [4]. A dialog controller initiates a half-duplex or full-duplex communication when desired by two nodes. Synchronization are services that use checkpoint to secure data and eliminate errors. The Point-to-Point Tunneling Protocol (PPTP) and Network Basic Input/output System (NetBIOS) are the primary session layer protocols [2]. NetBIOS protocols facilitates communication between computer applications over a network while PPTP provides a guideline for establishing a connection with a virtual private network. Gateways and firewalls are the basic devices used within the session layer to establish sessions and provide security of connections.

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OSI MODEL LAYERS Presentation Layer The presentation layer is responsible for the manipulation of data from users to ensure they are in the proper format for transmission through a network. The layer offers a network multiple services such as translation and compression. Translational services facilitate the conversion of data into relevant types while compression services minimize the number of bids to specific sizes that are ideal for transmission. Primary protocols used in the presentation layer are Secure Sockets Layer (SSL) and...