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Network communication · Networks and the internet

The elements of a network

It's 9 p.m., you're about to stream the big game, and the Wi-Fi cuts out. Is the problem your phone, the router, or the whole internet? Behind your connection there are specific parts with their own names and jobs. Let's get to know them, and at the end we'll come back to this question.

What is in a home network

Diagram of a home network in which a central router connects four devices by Wi-Fi: cell phone, tablet, game console and television. Router phone tablet console TV

The full chain looks like this: your devices connect to the router, the router connects to your ISP, and the ISP connects to the rest of the internet.

Chain of a connection: devices connect to the router, the router to the ISP, and the ISP to the internet. devices router ISP internet local network (home) on the left, outside networks on the right
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Make a list of at least five devices currently connected to your home (or classroom) router and highlight which one surprises you most to find on a network, explaining…

Make a list of at least five devices currently connected to your home (or classroom) router and highlight which one surprises you most to find on a network, explaining why.

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Describe in words (you may use a sketch in your notebook to help you) your home or classroom network: what devices are connected, how each one connects (cable or Wi-Fi),…

Describe in words (you may use a sketch in your notebook to help you) your home or classroom network: what devices are connected, how each one connects (cable or Wi-Fi), and which component links them to the internet. Identify what you think is the weakest point of that network.

Solve

The router, the center of the network

Diagram of a central router that creates the home's local network: it connects to the PC by cable, to the phone by Wi-Fi and to the internet through the ISP's line. internet ISP line Router PC cable phone Wi-Fi local network (home)

Bigger networks: schools, shops and hotels

A home router can handle a handful of devices. A high school with hundreds of students, a bakery or a hotel needs more: several access points spread around the building, a switch that connects them (and wired devices) by cable to one main router, and separate networks for different jobs.

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In a drawer there is an old router that is no longer used. Suggest two ways to reuse it to improve your home network (for example, as an access point in another room or…

In a drawer there is an old router that is no longer used. Suggest two ways to reuse it to improve your home network (for example, as an access point in another room or as a repeater) and explain the minimum setup needed in each case.

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The principal of a high school with three hundred students proposes replacing the entire school network installation with a single standard 30 dollars home router,…

The principal of a high school with three hundred students proposes replacing the entire school network installation with a single standard 30 dollars home router, arguing that "if it provides a connection to four people at the same time at home, here it will be enough to set a password for everyone". Refute his proposal by technically justifying three serious problems that will occur on the first day of class (related to connection saturation, signal range, and security) and design the basic infrastructure that the school actually needs to provide service to all classrooms.

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A bakery wants to connect its cash register, receipt printer and the owner's cell phone, as well as offer free Wi-Fi to customers. Design the network: what components it…

A bakery wants to connect its cash register, receipt printer and the owner's cell phone, as well as offer free Wi-Fi to customers. Design the network: what components it needs, how each device connects, and why customers should use a network separate from the cash register.

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The owner of a three-story hotel wants good Wi-Fi coverage in all rooms. His initial idea is to place the router at the reception desk (first floor) and two standard…

The owner of a three-story hotel wants good Wi-Fi coverage in all rooms. His initial idea is to place the router at the reception desk (first floor) and two standard wireless Wi-Fi repeaters in the hallways of the upper floors. Predict two problems that this solution will have (in terms of speed loss and stability) and design a more effective technical alternative indicating what network elements would be needed, how the floors would physically communicate, and why it is essential to separate the guest network from the hotel management network.

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To prevent students from searching for answers on the internet with their phones during exams, the administration of a high school proposes unplugging all the school's…

To prevent students from searching for answers on the internet with their phones during exams, the administration of a high school proposes unplugging all the school's routers and Wi-Fi access points during that week. Critically evaluate this measure by identifying at least three services or devices at the school (other than students' cell phones) that will unexpectedly stop working, and design a technical alternative that prevents students from browsing the internet without having to shut down the school's network.

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What is a router? Explain in your own words the two main tasks it performs in your home network and where it is usually located.

What is a router? Explain in your own words the two main tasks it performs in your home network and where it is usually located.

Solve
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The figure shows a home network with its devices, but the central device is covered with a question mark, as shown in the diagram. Which device is marked with "?" and…

The figure shows a home network with its devices, but the central device is covered with a question mark, as shown in the diagram.

LOCAL NETWORK internet ? PC cable Printer Cell phone Laptop

Which device is marked with "?" and what task does it perform between the local network and the internet? Also indicate which devices in the figure connect by cable and which by Wi-Fi, and explain what you noticed to find out.

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Explain what a Wi-Fi access point is and how it differs from a router. Hint: at home there is usually a single device that does everything, whereas at school there are…

Explain what a Wi-Fi access point is and how it differs from a router. Hint: at home there is usually a single device that does everything, whereas at school there are many access points located along the hallways.

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Cable or Wi-Fi: two ways of reaching the router

A router with antennas connected to a desktop computer by a network cable with RJ45 connectors and to a cell phone by Wi-Fi waves travelling through the air. Router network cable (RJ45) desktop computer Wi-Fi waves through the air phone
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The network cable connector is different from USB and does not fit into its port. Explain why each type of cable has its own connector shape and what problems this…

The network cable connector is different from USB and does not fit into its port. Explain why each type of cable has its own connector shape and what problems this prevents when setting up a network.

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Your brother plays online games from his room over Wi-Fi and complains that "it lags". Analyze whether connecting his computer to the router using a cable could improve…

Your brother plays online games from his room over Wi-Fi and complains that "it lags". Analyze whether connecting his computer to the router using a cable could improve the connection, explaining the differences between cable and Wi-Fi in terms of speed, stability, and interference.

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In the computer lab almost all computers use cables, whereas at home almost everything uses Wi-Fi. Compare both decisions, considering the number of devices, the…

In the computer lab almost all computers use cables, whereas at home almost everything uses Wi-Fi. Compare both decisions, considering the number of devices, the stability needed in each place, and the convenience of moving devices around.

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Local network and internet: they are not the same thing

Diagram of a home local network with a router that connects the computer and the printer to each other and, through an ISP connection, to the internet; if the internet is cut off, the computer and the printer can still communicate. local network router PC Printer internet ISP networknetwork of networks
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When the internet goes down at home, the printer connected to the computer still works, but you cannot watch online videos. Explain which network you are using in each…

When the internet goes down at home, the printer connected to the computer still works, but you cannot watch online videos. Explain which network you are using in each case (the home local network or the internet) and the difference between the two.

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True or false? Justify each answer: (a) home Wi-Fi can keep working even if the internet goes down; (b) any Wi-Fi enabled device can connect to any network without a…

True or false? Justify each answer: (a) home Wi-Fi can keep working even if the internet goes down; (b) any Wi-Fi enabled device can connect to any network without a password; (c) the lights on the router indicate whether it is working properly; (d) the further away from the router, the better the signal strength.

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Can a cell phone be "connected to Wi-Fi" and at the same time have no internet access? Explain the difference between connecting to the router's local network and…

Can a cell phone be "connected to Wi-Fi" and at the same time have no internet access? Explain the difference between connecting to the router's local network and reaching the internet, and describe a situation in which this would happen.

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After a storm passes, you try to browse the internet from your computer and the browser says "No connection". However, you verify that you can print without any issues…

After a storm passes, you try to browse the internet from your computer and the browser says "No connection". However, you verify that you can print without any issues on the living room network printer and open documents stored on another computer in the house. Your brother claims: "The router is broken and the home network is down". Refute his claim by demonstrating which part of the network is still working and which part has failed, and explain what physical checks you would carry out on the router's indicator lights to find out whether the fault is inside your house or in the internet service provider's line.

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When the Wi-Fi doesn't reach well

A weak signal also matters for safety: a router's signal passes through walls, so a neighbor may see your network name. That is why a strong password (and encryption) protects you even when the signal leaks outside your house.

Wi-Fi coverage: the router's waves weaken with distance and when passing through a wall, and the phone ends up in a weak-signal zone. wall router phone weak zone signal: strong medium weak more distance and more obstacles = less signal
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At home, the Wi-Fi signal is very weak in the room farthest from the router. Suggest two different solutions (moving the router, installing an access point or repeater,…

At home, the Wi-Fi signal is very weak in the room farthest from the router. Suggest two different solutions (moving the router, installing an access point or repeater, running a network cable...) and compare their advantages and disadvantages before deciding which one you would recommend.

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The cell phone shows full Wi-Fi bars, but videos do not load. Explain how it is possible to have a "strong signal" and no internet access at the same time, and describe…

The cell phone shows full Wi-Fi bars, but videos do not load. Explain how it is possible to have a "strong signal" and no internet access at the same time, and describe a simple test to find out whether the problem is with the home Wi-Fi or with the internet connection.

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Your neighbor sees the name of your Wi-Fi network on their cell phone list. Explain how far a router's signal can reach, what things weaken it (walls, floors, distance),…

Your neighbor sees the name of your Wi-Fi network on their cell phone list. Explain how far a router's signal can reach, what things weaken it (walls, floors, distance), and why the password protects you even if the signal extends beyond your house.

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In a home, the router is in the living room and the connection works at maximum speed. However, in the bedroom at the end of the hall, located after a long hallway and…

In a home, the router is in the living room and the connection works at maximum speed. However, in the bedroom at the end of the hall, located after a long hallway and across the kitchen and a bathroom with tiles and pipes, the Wi-Fi signal barely reaches and video calls cut out. Analyze which physical factors are weakening the signal along that path, explain why replacing the laptop with one that has a more powerful processor will not help at all, and design two viable technical solutions to have a quality connection in the bedroom, justifying which one offers greater reliability.

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Summary

Back to the start: if the game stream stops, check whether other devices still reach the router (local network OK) and whether any site loads (internet OK). That tells you whether the fault is the phone, the router or your ISP.

See all the exercises in this section