The Open Systems Internconnection (OSI) model is a theoretical framework that separates the different aspects of networking into seven layers. Understanding these layers and evaluating how they are interconnected and the taxonomy used will provide greater knowledge and assist you to develop skills in the realm of networking.
apply telecommunication and network technical knowledge to address the following elements.
Describe the seven layers of the OSI Model.
Compare the relationship between the OSI Model and the TCP/IP protocol using both a graphical and descriptive representation.
Apply standard principles of design to the conceptualization of the OSI model and explain how a network engineer can use the OSI model to help troubleshoot a networking problem.
Explain in which layer of the OSI model the following networking devices and functions can be found. Using your required sources, support your choice of the OSI model layers with a brief explanation of each of the following.
Switches
Routers
Data encryption
Error detection
Remote file access
Email client
Full Answer Section
The seven layers of the OSI model are:
- Physical layer: The physical layer is responsible for the transmission of data over the physical medium, such as a cable or wireless signal. It defines the electrical and mechanical specifications for the network, such as the voltage levels and the bit rate.
- Data link layer: The data link layer provides error detection and correction for the physical layer. It also provides addressing so that data can be sent to the correct destination.
- Network layer: The network layer is responsible for routing data packets from the source to the destination. It uses addressing to determine the route that the data packets should take.
- Transport layer: The transport layer provides reliable communication between two hosts. It ensures that data is delivered without errors or loss.
- Session layer: The session layer establishes and manages a communication session between two hosts. It also handles synchronization and recovery in case of errors.
- Presentation layer: The presentation layer ensures that data is formatted in a way that is understandable by the receiving host. It also handles compression and decompression of data.
- Application layer: The application layer is the highest layer of the OSI model. It provides services to applications, such as file transfer, email, and web browsing.
2. Compare the relationship between the OSI Model and the TCP/IP protocol using both a graphical and descriptive representation.
The OSI model and the TCP/IP protocol are two different ways of conceptualizing networking. The OSI model is a theoretical framework that divides networking into seven layers, while the TCP/IP protocol is a specific set of protocols that implement the functions of the OSI model's lower layers.
A graphical representation of the relationship between the OSI model and the TCP/IP protocol is shown below:
OSI model and TCP/IP protocol
The OSI model is shown on the left, and the TCP/IP protocol is shown on the right. The layers of the OSI model are stacked on top of each other, and the protocols of the TCP/IP stack are shown below each layer.
A descriptive representation of the relationship between the OSI model and the TCP/IP protocol is as follows:
- The physical layer of the OSI model is implemented by the Ethernet protocol in the TCP/IP stack.
- The data link layer of the OSI model is implemented by the Internet Protocol (IP) protocol in the TCP/IP stack.
- The network layer of the OSI model is implemented by the Internet Control Message Protocol (ICMP) and the Address Resolution Protocol (ARP) in the TCP/IP stack.
- The transport layer of the OSI model is implemented by the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) in the TCP/IP stack.
- The session layer of the OSI model is not implemented in the TCP/IP stack.
- The presentation layer of the OSI model is not implemented in the TCP/IP stack.
- The application layer of the OSI model is implemented by a variety of protocols in the TCP/IP stack, such as the File Transfer Protocol (FTP), the Simple Mail Transfer Protocol (SMTP), and the Hypertext Transfer Protocol (HTTP).
3. Apply standard principles of design to the conceptualization of the OSI model and explain how a network engineer can use the OSI model to help troubleshoot a networking problem.
The OSI model can be used to troubleshoot networking problems by isolating the layer at which the problem is occurring. This can be done by understanding the functions of each layer and the protocols that are used in each layer.
For example, if a network engineer is troubleshooting a problem with data delivery, they would start by checking the physical layer. They would make sure that the cables are connected properly and that the network devices are powered on. If the problem is not at the physical layer, they would then check the data link layer. They would make sure that the network adapters are properly configured and that the data frames are being transmitted and received correctly.
The OSI model can also be used to identify the source of a networking problem. For example, if a network engineer is troubleshooting a problem with a specific application, they would start by checking the application layer. They would make sure that the application is properly configured and that it is communicating with the correct servers. If the problem is not at the application layer, they would then check the layers below.
