Networking is incredibly complex. To make it easier to understand, we break network protocols down into chunks. This module will test your understanding of layering, its advantages, and how to score full marks in the exam.
A layer is simply a division of network functionality. Each layer does its own specific job and then hands the data to the next layer down.
You (The Sender)
You write the letter. You don't care how the post office delivers it, as long as it arrives.
The Sorting Office
They route the letter by reading the address. They don't care about what you wrote inside.
The Delivery Driver
They physically drive the van. They just transport the items on the road.
Match the real-world postal layer on the left to its digital networking equivalent on the right.
Match all layers to continue.
This is the most highly examined part of this topic. You must memorise these four advantages.
Layers are independent. You can change or update one layer without breaking the others.
Allows developers to focus on just one aspect (e.g., a web developer doesn't need to write Wi-Fi drivers).
Breaking a massive network down into smaller parts makes it easier to find and fix bugs.
Promotes standardisation so hardware from different manufacturers can communicate.
Read the scenario before the timer runs out. Which advantage of layering does it describe?
"A programmer building a chat app doesn't need to know how the network cable transmits binary."
Sort all scenarios to continue.
You do not need to memorise the specific functions of these four layers for OCR J277. However, you should recognise their names so you understand the context if they appear in a question!
Familiarise yourself with the names by building the stack. Click a block below to place it in the next available slot (from top to bottom).
Build the stack to continue.
A student has answered a 2-mark question. Click the two specific sentences that deserve a mark on the OCR mark scheme.
Q: The TCP/IP model uses layers. Explain why the TCP/IP model uses layers. [2 marks]
Using layers is good because it makes the internet a lot faster to load pages. Also, each layer is completely self-contained, meaning you can edit one without breaking the others. There are four layers in the model called Application, Transport, Internet and Link. This helps developers because they can specialise and focus on just one area of the network.
Find both marks to finish the lesson.
Excellent work, Student.