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1CP2-P-7.4 The four-layer TCP IP model

Part 4 of 6 · 1CP2-P-7 · Embedded systems, IoT and TCP/IP

The TCP/IP worksheet, establishing the four layers in order and the direction data moves through them.

Students will:

  • place the four layers in order and state the direction of travel
  • assign the right responsibility to each layer
  • describe two responsibilities of the transport layer
  • explain one benefit of a layered protocol model
  • follow a web request down the stack and back up at the receiver

Inside: 5 explanation cells, 3 multiple-choice questions, 2 fill-in-the-blanks cells and 4 written answers. 20 marks, about 45 minutes.

Series: 1CP2-P-7 · Embedded systems, IoT and TCP/IP, part 4 of 6.

Shared by Coding PathwayVerified teacher

  • 14 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 17 Aug 2026

Preview

The whole resource, exactly as a class sees it. Answers and marking are held back.

The four-layer TCP/IP model

A layered protocol model divides network communication into responsibilities. The four TCP/IP layers, from top to bottom, are application, transport, internet, link. Agreed interfaces let different devices, operating systems and network technologies communicate without every layer needing to know every implementation detail.

1. Build the order and direction

Four-layer TCP/IP modelapplicationuser services and protocols: HTTP, HTTPS, FTP, emailtransportpackets, sequence and delivery/error checksinternetIP addresses and routing between networkslinklocal transmission: Ethernet or Wi-Fisender moves downreceiver moves upLayering lets different hardware and software communicate through agreed responsibilities.

At the sender, data moves down the stack as each layer performs its role and adds suitable control information. At the receiver, it moves up as corresponding information is interpreted and removed. The order is assessed exactly.

Fill in the blanks4 marks
From top to bottom the layers are gap 1, gap 2, gap 3 and gap 4.
  • application
  • internet
  • link
  • transport
Multiple choice1 mark

At a sending device, which direction does data move through the stack?

  • Alink to application only
  • Bapplication down to link
  • Cinternet directly to application
  • Drandomly between layers

2. Assign responsibilities

  • Application: services used by applications and their data-exchange protocols.
  • Transport: divides/manages data as packets, ordering and delivery/error checks.
  • Internet: IP addressing and routing packets between networks.
  • Link: transmission across the local connection using technologies such as Ethernet or Wi-Fi.

Descriptions should name the mechanism. Avoid saying every layer simply 'sends data'.

Fill in the blanks3 marks
Routing by IP belongs to the gap 1 layer. Local Ethernet transmission belongs to the gap 2 layer. Packet ordering and delivery checks belong to the gap 3 layer.
  • application
  • internet
  • link
  • transport
Written answer2 marks

Describe two responsibilities of the transport layer.

Use packet management, ordering, checking or delivery.

Students type their answer here.

Written answer2 marks

Explain one benefit of using a layered protocol model.

Connect separation of responsibilities to compatibility or change.

Students type their answer here.

3. Follow one web request

An application-layer web protocol forms the request. The transport layer manages packets and delivery information. The internet layer uses IP addressing and routers. The link layer carries data over the current local medium. At each router, link details can change while the destination IP purpose remains.

Written answer4 marks

Describe the four-layer journey of a web request from a laptop onto a network.

Give one correct role at each layer in top-to-bottom order.

Students type their answer here.

Multiple choice1 mark

Which layer is primarily responsible for routing packets using IP addresses?

  • Aapplication
  • Btransport
  • Cinternet
  • Dlink
Written answer2 marks

Explain what happens to data direction at the receiving device.

Name the bottom and top layers.

Students type their answer here.

Multiple choice1 mark

Which layer order is correct from bottom to top?

  • Alink, internet, transport, application
  • Bapplication, transport, internet, link
  • Ctransport, link, application, internet
  • Dinternet, application, link, transport

Route forward

You can order the four layers and assign their main responsibilities. Next you will attach the named application and link protocols to those layers and distinguish their purposes.