DGB 4: Network Protocols and Data Transmission

← Digital Literacy – Year 4

Digital communication works because devices follow shared rules. Network protocols define how data is addressed, divided into packets, transported, checked and interpreted. Students do not need to memorise every protocol detail, but they should understand how several protocols cooperate when a webpage, file or e-mail is transmitted.

Curriculum reference

Area	Classification
Competence area	Information
Perspectives	T, I
Focus	Functions of network protocols during data transmission
Competence	Explain why network communication requires protocols and describe the basic roles of packets, addressing, TCP/IP, HTTP(S), DNS and e-mail protocols.

Learning objectives

Students can:

explain what a network protocol is and why protocols are necessary;
describe how data is divided into packets and reassembled;
explain the basic role of IP addressing and routing;
distinguish the basic roles of TCP and IP;
describe HTTP and HTTPS when loading websites;
explain DNS as a system that resolves names to IP addresses;
name the roles of SMTP, IMAP and POP3 in e-mail;
identify protocols involved in file transfer and other services;
distinguish encrypted from unencrypted transmission at a basic level;
use simple diagnostic tools or simulations responsibly.

Learning content

What protocols do

A protocol is an agreed set of rules for communication. It defines formats, sequences and responses so that independent devices can exchange data reliably.

Data travels in packets

Large messages are normally divided into smaller units. Packets can travel through networks and are processed at the destination. Transport mechanisms help ensure that data can be put back together correctly where required.

Addresses, routes and delivery

IP provides addressing and enables packets to be forwarded across interconnected networks. Routers select paths based on network information; a user normally sees only the resulting service.

HTTP and HTTPS

HTTP defines how web clients and servers exchange requests and responses. HTTPS adds transport encryption and server authentication through TLS, which protects data in transit but does not guarantee that the website's content itself is trustworthy.

TCP and IP

IP is concerned with addressing and delivery between networks, while TCP provides a reliable connection-oriented transport service with ordering and retransmission. Other transport protocols also exist, but TCP/IP is a useful foundational model.

DNS

Domain Name System translates human-readable names such as example.org into information needed to reach the relevant server. DNS therefore acts like a distributed naming service rather than literally being a single telephone book.

E-mail protocols

SMTP is used for sending and relaying mail. IMAP keeps messages on a server and synchronises mailboxes; POP3 is designed primarily for retrieving messages. Modern services may hide these protocols behind web interfaces.

Security and troubleshooting

Encryption, certificates and secure protocol variants reduce the risk of interception and tampering. Simple tools such as ping, traceroute or browser developer information can help diagnose problems when used in authorised environments.

Classroom activities

Packet post

Simulate packets travelling through several stations, including sequence numbers and a missing packet.

Expected outcome: A physical model of packet delivery.

From click to webpage

Draw the steps from entering a URL to receiving an HTTPS response.

Expected outcome: A protocol-flow diagram.

Compare protocols

Match TCP, IP, HTTP(S), DNS, SMTP, IMAP and POP3 to their main roles.

Expected outcome: A protocol table.

Troubleshoot a network case

Identify whether a fictional failure is likely to involve naming, connectivity or a service.

Expected outcome: A diagnosis path.

Follow an e-mail journey

Trace sending, relay and mailbox access using the relevant protocol names.

Expected outcome: An e-mail flowchart.

Secure or open

Compare HTTP with HTTPS and explain what encryption protects and what it does not.

Expected outcome: A security explanation.

Protocol memory

Create matching cards with protocol names, functions and examples.

Expected outcome: A revision game.

Explain to younger students

Create a simple explanation using a transport or postal analogy and note where the analogy breaks down.

Expected outcome: An age-appropriate explanation.

Transmission flowchart

Create a layered diagram showing application, transport and network functions.

Expected outcome: A labelled diagram.

Mini-debate

Discuss when reliability, speed, encryption or low overhead might matter most.

Expected outcome: A justified conclusion.

Self-check

I can explain why protocols are needed.
I can describe packet-based transmission.
I know the basic roles of TCP, IP, HTTP(S), DNS and e-mail protocols.
I understand that HTTPS protects transport but not the truthfulness of content.
I can use a simple layered view of network communication.
I can distinguish basic connectivity problems from naming or service problems.