C53 · Topic 4.1 · 40 minutes · CSN-1.A, CSN-1.B, CSN-1.C, CSN-1.D
Networks, addresses and protocols
By the end you can:
- Distinguish a network from a device.
- Explain addressing, naming and shared protocols.
- Separate bandwidth from latency.
Start here; no earlier topic is required.
- Protocol
- An agreed set of rules for communicating information.
- Bandwidth
- The maximum rate at which data can be transmitted through a connection under stated conditions.
Understand
A computer network connects devices so they can communicate. The Internet is a network of interconnected networks, not one central computer or one organisation’s collection of websites. Shared protocols support interoperability across different hardware and software; open agreed standards help new systems join without every device using the same operating system.
IP addresses support delivery to network destinations, while domain names provide human-readable names that can be resolved to addresses. DNS is a naming service, not a guarantee that a destination is trustworthy. Bandwidth describes a transmission-rate capacity; latency describes delay. A connection can have high capacity and still noticeable delay.
Worked example
A fictional school laptop requests a service using school.example.
- The name can be looked up to obtain an IP address; it is not itself an encryption method.
- Packets use addressing and protocol rules to travel across connected networks.
- Different device manufacturers can communicate through those shared rules, not because they share one operating system.
Explore each concept
Choose a concept, change its inputs and follow the explanation. Each example models the stated rule or scenario; completing it is practice rather than evidence of mastery.
- Devices, systems and networks
- Open protocols and scalability
- DNS naming versus trust
- Web versus Internet
- Reliable delivery versus best effort
Change it · step through · explain
Change an input, predict what will happen, then advance one step. Read why the state changes, reset and experiment. This fixed teaching model does not save progress or award XP.
Ready · Make a prediction
- ServicewebWaiting
- A packet is lostyesWaiting
Ready to explore: DNS, IP, TCP/UDP and Web services
Why: Change an input, predict the first effect, then advance one step.
Try this: Change one input or choose another listed case. Predict the effect, reset and compare the states and governing rule.
Step through and experiment
Change it · step through · explain
Change an input, predict what will happen, then advance one step. Read why the state changes, reset and experiment. This fixed teaching model does not save progress or award XP.
Ready · Make a prediction
- Input 14,1,3Waiting
Ready to experiment
Why: Predict the first change, then advance one step.
Try this: Compare 1,1,1,1 with 4,2,1,3. Both have four deliveries; only one has every position.
Check a misconception
Claim: The Internet and the Web are identical names for every network activity.
The Internet is infrastructure; the Web is one service using it.
Guided practice
Explain how a domain name differs from an IP address.
Work with a partner. Make a prediction, compare your reasoning, then identify the rule that supports your answer.
Independent transfer
A link can send many bits per second but responses are delayed. Is that contradictory?
Exit check
Why do shared protocols matter more than identical device brands?
Write your reasoning before comparing with a classmate. If your teacher assigned this task, submit it through My classes to save your work and receive feedback.
Check yourself
Your practice so far
Check an answer to see its rationale.