IT320 Unit 1

Describe each of the seven layers of the OSI model.

• Layer 1 is the Physical Layer. The job of the physical layer is to format the signal according to mechanical electrical and functional parameters
• Layer 2 is the Data Link Layer. It is used to tie the network protocol to the physical medium
• Layer 3 is the Network Layer. It assigns source and destination IP addresses it also assigns which port to forward the network.
• Layer 4 is the Transport Layer. This layer is responsible for interfacing the higher order layer with the lower layers.
• Layer 5 is the Session Layer. This layer establishes and monitors communication between two end devices. IT ensures both devices are talking to the application layer.
• Layer 6 is the Presentation Layer. It is translating and presenting the data to the user in a readable format.
• Layer 7 is the Application Layer. This end user interacts with the application layer when creating a document.

2. What are some networking troubleshooting tools? Describe each tools purpose and what it can tell you about the network/potential problem The Seven Layer OSI model is a great troubleshooting tool. If you work your way up thru the different layers you can actually narrow down the problem and quickly solve it. You can begin at either end of the model but I always start at the first layer. By quickly checking the Physical Layer, where most of the problems lie, you can solve most problems with connection issues. As you work up the layers you can narrow down where the problem might be.