OSI Layer Model

QUESTION:

In this section, you are expecting to explain on how the data travels from the student’s computer to reach the OnlineLearning System server which is in the OUM IT Center. The explanation should be related the OSI Layer Model. Explain the possible network components involves throughout the communications. Illustrate the diagram to support your explanation.

Explanation about OSI Layer: 

Application Layer (7^th Layer): The presentation layer formats or converts data for the application layer based on the application's syntax or semantics. As a result, it's also known as the syntax layer. This layer can also manage the application layer's encryption and decryption specifications. 

Presentation Layer (6^th Layer): Based on the syntax or semantics that the application embraces, the display layer formats or converts data for the application layer. It is also known as the syntax layer as a result of this. The encryption and decryption required by the application layer can be handled by this layer as well. 

Session Layer (5^th Layer): The session layer is in charge of coordinating conversations between computers. At layer 5, a session or link between machines is created, controlled, and terminated. Authentication and reconnections are also part of the session layer facilities. 

Transport Layer (4^th Layer): The transport layer is in charge of data packet distribution and error checking. It controls the size, sequencing, and, eventually, data transmission between systems and hosts. TCP, or Transmission Control Protocol, is one of the most common transport layer examples. 

Network Layer (3^rd Layer): Receiving frames from the data link layer and transmitting them to their intended destinations based on the addresses found within the frame is the responsibility of the network layer. Logic addresses, such as IP addresses, are used by the network layer to locate the destination (internet protocol). Routers are a critical component at this layer, as they simply route data where it needs to go between networks.

Data Link Layer (2^nd Layer): Directly linked nodes are used at the data link layer to perform node-to-node data transfer in which data is packaged into frames. Errors that may have happened at the physical layer are also corrected by the data link layer. 

Physical Layer (1^st Layer): The OSI Model's lowest layer is concerned with electrically or optically transferring raw unstructured data bits through the network from the sending device's physical layer to the receiving device's physical layer. Voltages, pin layout, cabling, and radio frequencies are examples of specifications. Network hubs, cabling, repeaters, network adapters, and modems are examples of “physical” services found at the physical layer. 

How the data travels from the lecturer’s computer to reach the OnlineLearning System server : 

Data reaches the "Physical layer," which is layer 1 of the OSI model, from the student's PC first. This layer deals with unstructured, raw bit-stream data sent over a physical medium. As a result, data flows in the form of bits from the student's PC to the physical medium of cable. The data is then transferred to the following sheet.

Data link layer is where the raw data from the physical layer is being transformed into a reliable link in the sender machine (device of OUM’s student) while in the receiver machine (server in IT center), it is vice versa. In the student’s device, the frame received from the network layer will divide the stream of bits into frames. There will be two types of frames which are H2 (Header) and T2 (Trailer). Physical addressing is useful for defining the frame's sender and receiver (the next destination that connects their network). As for Trailer, it will be added at the end of PDU that contains error detection. If the receiver detects some damaged or duplicate frames, it will discard and ask the sender to send the frame back.

The data is then passed to the "Network layer," which is layer 3 in the OSI model. This layer is in charge of figuring out how to get from the transmitting machine to the receiving computer. It's also in charge of sending messages and converting logical addresses into physical addresses. The data is in the form of packets, which are then transmitted via an optimised path from source to destination. The data is then passed on to the next layer.

The data is then passed to the "Transport Layer," which is layer 4 in the OSI model. This layer is in charge of ensuring that all data is delivered in the correct order, with no errors and no data loss. The data is in the form of datagrams, and this layer is responsible for the data's transportation in order to ensure that it is delivered in a secure and error-free manner. The data is then received by the recipient, which is the OUM Campus Network

The data then moves to the "Session Layer," or layer 5 of the OSI model. This layer handles name recognition and other tasks, such as user authentication and resource access security, which are required for processes to communicate over the network. The student's request is processed at this layer by the OUM server. The "Presentation layer" is where the required data is presented to the student in a format that is understandable.

Application layers are where the direct communication between the student and network happened. It provides the user interface and support for services such as shared database management, sending or store e-mails and file transfer. The student also can access and manage the files in a remote host, retrieve files from a remote computer for use in a local computer, and manage or control files in a remote computer locally.