What is the TCP/IP model?

The TCP/IP model divides network communication into four layers. Each layer has its own job and its own protocols.

Name the four layers of the TCP/IP model, from top to bottom.

The layers are application, transport, internet and link.

Why is network communication split into layers?

Each layer can be designed and changed without affecting the others. A fault can be traced to one layer, and different manufacturers can build compatible parts.

What does the application layer do?

The application layer provides the network services that programs use to communicate. HTTP, HTTPS, FTP, SMTP, POP3 and IMAP all work at the application layer.

What does the transport layer do?

The transport layer splits data into packets and numbers them in order. The transport layer uses TCP to check that every packet arrives undamaged.

How does the transport layer make sure data arrives complete?

The receiving computer sends back an acknowledgement for each packet that arrives. Any packet that is missing or damaged is sent again.

Edexcel GCSE Computer Science 1CP2

Computational Thinking

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Computers

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Networks

Topic overview LANs, WANs and the structure of the internet Wired and wireless connectivity and network speed Network protocols The four-layer TCP/IP model Bus, star and mesh topologies Network security and protection

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Networks

The four-layer TCP/IP model

3 things to know
Paper 1

Overview

The application, transport, internet and link layers, what happens to data going down and up the layers, packets and their headers, and sending an email.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What happens to data at the internet layer and the link layer of the TCP/IP model?

Key term

Why is network communication layered, and what does the application layer provide?

Key term

How does the TCP/IP model handle an email being sent?

Questions from this subtopic

Each one with the model answer underneath.

1
What is the TCP/IP model?
Model answer
The TCP/IP model divides network communication into four layers. Each layer has its own job and its own protocols.
2
Name the four layers of the TCP/IP model, from top to bottom.
Model answer
The layers are application, transport, internet and link.
3
Why is network communication split into layers?
Model answer
Each layer can be designed and changed without affecting the others. A fault can be traced to one layer, and different manufacturers can build compatible parts.
4
What does the application layer do?
Model answer
The application layer provides the network services that programs use to communicate. HTTP, HTTPS, FTP, SMTP, POP3 and IMAP all work at the application layer.
5
What does the transport layer do?
Model answer
The transport layer splits data into packets and numbers them in order. The transport layer uses TCP to check that every packet arrives undamaged.
6
How does the transport layer make sure data arrives complete?
Model answer
The receiving computer sends back an acknowledgement for each packet that arrives. Any packet that is missing or damaged is sent again.

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