OSI Layer Model

OSI Layer Model

 

1. Physical Layer

    Transmit raw bit stream over the physical medium.

2. Data Link Layer

    Defines the format of data on the network.

3. Network Layer

    Decides which physical path the data will take

4. Transport Layer

    Transmit data using transmission protocols including TCP 

5. Session Layer

    To maintain the connections and responsible for controlling ports and session

6. Presentation Layer

    To ensure that the data is in a usable format and is where the data is being encrypted occurs.

7. Application Layer

    The interaction layer of the human-computer, where the application layer can access network services

how the data travels from the lecturer’s computer to reach the OnlineLearning System server which is in the Cobham College IT Center

In the OSI (Open Systems Interconnection) model, data travels through a series of layers, each of which is responsible for a specific aspect of transmitting the data. Here's how the data might travel from a lecturer's computer to an online learning system server using the OSI model:

1. At the Physical layer, the data is transmitted over a physical medium, such as a network cable or wireless connection.

2. At the Data Link layer, the data is divided into smaller units called frames, which are transmitted over the physical connection.

3. At the Network layer, the frames are routed to their destination using logical addressing (e.g., IP addresses).

4. At the Transport layer, the data is divided into smaller units called segments, which are transmitted over the network connection. The Transport layer is responsible for ensuring that the segments are delivered reliably to the destination.

5. At the Session layer, the data is organized into a series of dialogues or "sessions" between the two devices.

6. At the Presentation layer, the data is converted into a standard format that can be understood by both the sender and receiver.

7. At the Application layer, the data is delivered to the online learning system server and is processed according to the specific application being used (e.g., a web browser).

Illustration data flow inside OSI layer Model

 The possible network components involve throughout the communications.

Network Devices: Network devices, also known as networking hardware, are physical devices that allow hardware on a computer network to communicate and interact with one another. For example, Repeater, Hub, Bridge, Switch, Routers, Gateaway, Router, and NIC, etc.

For this scenario, there are a few possible network components throughout the communications:

 

1. Physical Layer:

Hub – A hub connects multiple wires together from different branches so that they function as a single network. Data has to pass through the hub before it can be sent to other devices which in this case is from the home network to the IT centre.

Cable – A cable is simply a device to connect two devices for the purpose of establishing a connection. In this case, an ethernet cable is used to form a connection between a device to the hub.

 

Repeater – A hub is basically a multi-port repeater which functions to regenerate signal over the same network to extend the length to which a signal can be transmitted. This allows the connection between home network with the online learning system to not be corrupted.

 

2. Data Link Layer:

Switch – It works similarly as the hub but there’s a major difference in where the switch can perform error checking before forwarding data, which makes it very efficient as it does not forward packets that have errors and forward good packets selectively to the correct port only.

 

Bridge - The basic purpose of a bridge is to forward the frames to their destination.

 

3. Network Layer:

Router - A router is a device like a switch that routes data packets based on their IP addresses. It functions to receive the packets from the data link layer and forward them to their destination.

 

4. Session Layer:

Gateway – It is a passage to connect two networks that may work upon different networking models. They work as messenger agents that take data from one system, interpret it, and transfer it to another system which is the presentation layer.

5. Application Layer:

Encryption device: It is capable of encrypting the data which is to be sent over the network. In this case, HTTPS commands can be read and granted permission to the user to access the website.