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Intro to CS 9-10 / Week 11 / Friday
5/6
Week 11 · Systems and the Internet

Friday

Impact Friday: Shared networks
// Packets, paths and a network that keeps working
⏱ about 20 min

Friday: Impact Friday: Shared Networks

The outpost has a new visitor dome, and it has its own open wireless network for guests.

Comet wants Beacon to use it. "It is closer than our relay, so it must be faster."

Wren checks the network list on his tablet. "What do you notice? There are two networks called Dome Guest. One of them appeared this morning."

"That is odd," Comet says. "Who put up a second one?"

Nova hovers near the dome door. "Ask who runs a network before you trust it with anything," she says.

Comet slowly puts her tablet away. "Beacon stays on our own relay."

Public networks

Data sent over public networks can be intercepted, analyzed and even changed by someone else.

One way this can happen is through a rogue access point.

A rogue access point is a wireless access point that gives unauthorized access to secure networks.

A safe habit: ask a grown-up before joining any public network, and never send personal information over one.

SPOT THE RISK
  • Read the question.
  • Tap your answer.
A second Dome Guest network appears with no explanation. What should the crew do?
What can happen to data sent over a public network?
What is a rogue access point?

Sensitive data and malware

Malware is software meant to damage a computing system or take partial control of it.

If malware reached the Beacon sensor box, it could change readings or send them somewhere they should not go.

That is why sensitive data need protecting at every layer, from the network to the app.

Next week, Beacon's launch review checks its defenses one by one.

StatementTrue or false?
Data on a public network can be intercepted.?
A rogue access point gives authorized, safe access.?
Malware is software meant to damage a system or take control of it.?
A network that is closer is always safer.?
WHY THIS EXERCISEKnowing the risks of shared networks helps you choose safe habits.

Week review

OUR WEEK, IN ORDER
  • ?We stacked the layers and timed a parallel job.
  • ?We split a message into numbered packets.
  • ?We mapped the relay network and its paths.
  • ?We broke links and rerouted packets in the paper relay.
  • ?We learned why shared networks need care.
WHY THIS EXERCISEThe week moved from paths, to packets, to reliable systems, to safe ones.
WEEK CHECK
  • Read the question.
  • Tap your answer.
Packets arrive out of order. What puts the message back together?
Why did the relay survive one broken link in the lab?
A chain of directly connected devices from sender to receiver is a ____.
Software meant to damage a system or take control of it is ____.
What do you call a wireless access point that gives unauthorized access to secure networks? Type the two-word name, starting with rogue.
WHY THIS EXERCISEKnowing the name helps you recognize the risk.
Try it
With a grown-up, talk about which networks your family devices join when you are away from home.
Make a family rule for public networks together.
On paper, sketch a simple poster for the visitor dome that reminds guests to check a network before joining it.

Excellent week, developer. Tomorrow's Mission Quest is a family packet race.

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