Cmgt/554 Week 2 Essay example

1: Physical layer: The purpose of the physical layer is it deals with the hardware components, like cads and cables for sending and receiving data of a carrier.

The fifth layer is the session layer this establishes a connection,this layer makes and sets up the connection using co ordinates and could terminate conversations links. the session layer produces services that make authentication after an interruption and not only that but it can reconnect.and as well as the transporting layer it can also have the TCP and the UDP can provide services for all most all applications.An application layer is an abstraction layer that specifies the shared protocols and interface methods used by hosts in a communications network. The application layer abstraction is used in both of the standard models of computer networking; the Internet Protocol Suite (TCP/IP) and the Open Systems Interconnection model (OSI model).Although both models use the same term for their respective highest level layer, the detailed definitions and purposes are different.In TCP/IP, the application layer contains the communications protocols and interface methods used in process-to-process communications

• “Application - The Application Layer is the layer that most network users are exposed to, and is the level at which human communication happens. HTTP, FTP, and SMTP are examples of the application layer protocols the Patton-Fuller will now be utilizing for communicating electronically” (Network Design, 2012).

This makes sure the data transferred is in the right order, error free and reliable from beginning to end. The Network Layer is the third layer of the model and its function is to interpret the network addresses into physical addresses and figure out how to direct them from the sender to the receiver. The next layer is the Data Link Layer, this is the second layer and it separates the data it receives from the Network layer into specific frames so they can be transmitted by the Physical layer. Frames are packages for moving data, they include the raw data, the sender and receiver’s addresses, as well as error checking and control information. This makes sure the frames are delivered to their destination without any problems. The physical layer is the first layer and the lowest, the protocols at this layer recognize and receive the frames from the Data Link layer. They also monitor data error and set data transmission

In the seven layers of the OSI, control is passed between layers. The model is theoretical, but tells us how a network takes the data sent from the application all the way down to the physical layer and out, to in the physical layer and back up all the way to the application layer. This Model has nothing to do with the actual functions of the process. Instead it is a concept of the framework, so the complexities of a network can be broken down and understood (Beal, 1999).

The first three layers of the OSI is typically what a router needs to route traffic. The first three layer are physical, data link and network. The highest level the OSI decide where to forward traffic to is the transport layer which is located in the host layers.

Layer 5 which is the Session layer allows the applications to establish a session by connecting systems. It provides a synchronisation between communication computers as well as manages and terminates the session if required and this depends on how the communication will take place. It also provides operation such as simple, half duplex and full duplex.

6. PRESENTATION (layer 6) – this layer provides independence from differences in data representation. E.g. encryption.

Framing: Data link layer receives the data from the network layer & divide it into manageable units called frames.

The application layer: this layer allows different applications to communicate with each other’s. In order to exchange different data over the network connection, the protocols included in this layer set up the standards such as DNS, HTTP, FTP. The data coded in this layer will be encapsulated to transport layer for further packing.

As the data packet moves from the upper to the lower layers, headers are _______.

Transmission Path Level: This extends between network elements that assemble and disassemble the payload of a transmission system. For end-to-end communication, the payload is end-user information. For user-to-network communication, the payload may be call-control signaling information (call setup and call termination). Cell delineation and header error-control functions are required at the end points of each transmission path.

A given layer in the OSI model generally communicates with three other OSI layers: the layer directly above it, the layer directly below it, and its peer layer in other networked computer systems. The data link layer in System A, for example, communicates with the network layer of System A, the physical layer of System A, and the data link layer in System B. The following figure illustrates this example.

The physical layer specifics the function details for initiating, keeping up and turning off the physical link when moving the bits of data over the physical media such as copper, fibre or wireless. So it will takes your data bits of ones and zeros covert them to what is needed to transfer over that type of media so for example change bits into electrical signals for copper cables then will covert it back to ones and zeros once it reaches its destination to send up OSI model layers.

\textbf{Service Layer:} The second layer is formed by the services that support the applications and use the abstractions implemented by the drivers to communicate with the devices. Among the items in this layer are: Storage, Scheduling, Authentication, Settings, Communication, Events, Conflict Management, Context Management.