OSI Model

In this section, we are expected to explain on how the data travels from the lecturer’s computer to reach the ULearn System server which is in the UTeM IT Center. The explanation should be related the OSI Layer Model, explain the possible network components involves throughout the communications, and illustrate the diagram to support the explanation.

Answer:

The OSI Model (Open System Interconnection Model) is a conceptual framework used to describe the functions of a networking system. The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software. In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Physical layer, Data Link layer, Network layer, Transport layer, Session layer, Presentation layer, and Application layer.

Application Layer

At this layer, both the end user and the application layer interact directly with the software application.

Presentation Layer

The presentation layer formats or translates data for the application layer based on the syntax or semantics that the application accepts. This layer also can handle the encryption and decryption required by the application layer.

Session Layer

The session layer controls the conversations between different computers. A session or connection between machines is set up, managed, and termined at layer 5. Session layer services also include authentication and reconnections.

Transport Layer

The transport layer manages the delivery and error checking of data packets. It regulates the size, sequencing, and ultimately the transfer of data between systems and hosts. For example, TCP (Transmission Control Protocol). 

Network Layer

The network layer is responsible for receiving frames from the data link layer, and delivering them to their intended destinations among based on the addresses contained inside the frame. The network layer finds the destination by using logical addresses, such as IP (internet protocol).

Data Link Layer

At the data link layer, directly connected nodes are used to perform node-to-node data transfer where data is packaged into frames. The data link layer also corrects errors that may have occurred at the physical layer.

Physical Layer

The lowest layer of the OSI Model is concerned with electrically or optically transmitting raw unstructured data bits across the network from the physical layer of the sending device to the physical layer of the receiving device.

Based on the scenario above, the lecturer is uploading the noted into the ULearn system. First, the lecturer would see the interface of the website and is provided by the Application Layer. The function of Application Layer is to display the information received data exchange to the user. The protocol are used when the lecturer is reach ULearn system server FTP (File Transmission Protocol) to transfer the data and pass the data to the Presentation Layer.

In the Presentation Layer, the data format will be equalized and the encryption and decryption process will completed if needed and the data will pass to the Session Layer.

While in Session Layer, the conversations session will be authentication by sending the request and respond to determined if the requested session is valid or not. If yes, the data will pass to the next layer.

Then the data is pass to the Transport Layer. In this layer, it manages the delivery and error checking of data by TCP and UDP protocols. The data will segmented then separated into packets at the Network Layer.

Next, Network Layer. In this layer, receives data segment from Transport Layer and adds logical address (IP address). Every computer has a unique IP address. This layer will checking the devices communicating are the same network or not. It also specifies the standards and protocols which are used to move the data packets across the network.

The data packets are encoded and decoded into bits and it will form frames and it sent to the Physical Layer. This layer represents the electrical and physical representation of the system. It will stored the data in the ULearn System Server that is located in the IT Centre.