AP CSP 4.2 Exercise 2: Redundancy Audit

Big Idea 4 · Topic 4.2 · Exercise 2

Redundancy Audit

25 minutes - 4 systems - audit and prescribe

Back to the Topic 4.2 lessonAll CSP topics

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Scenario 1 · Foundational

Jefferson Middle School's morning announcements, bell schedule, and hallway clocks all run through one control box in the main office. Every classroom speaker is wired directly to that box in a star layout. Last week, the failure of a single power strip silenced the entire building for a day. The principal asks whether the system is fault-tolerant.

Vulnerability found (the single point of failure + the fault-tolerance verdict):

Redundancy prescription + the resource cost accepted:

Enrichment - the reliability/scaling payoff of your fix:

Scenario 2 · Core

County General Hospital proudly reports 'full network redundancy': two separate fiber lines run from the building to two different Internet providers. Walking the property, an auditor notices that both lines exit the hospital through the same utility conduit under the parking-lot entrance - the exact spot where a contractor is scheduled to dig next month.

Vulnerability found (the single point of failure + the fault-tolerance verdict):

Redundancy prescription + the resource cost accepted:

Enrichment - the reliability/scaling payoff of your fix:

Scenario 3 · Core

A rural county links its six mountain fire-lookout towers by point-to-point radio in a chain: Tower 1 relays to Tower 2, Tower 2 to Tower 3, and so on down the line until Tower 6 reaches the ranger station. During last summer's storms, Tower 3 lost power - and every report from Towers 1 and 2 vanished for six hours at the height of fire season.

Vulnerability found (the single point of failure + the fault-tolerance verdict):

Redundancy prescription + the resource cost accepted:

Enrichment - the reliability/scaling payoff of your fix:

Scenario 4 · Challenge

A delivery startup brags that it is 'redundant everywhere': two web servers, two Internet providers, two power feeds, and servers in two cities. But every customer login flows through one authentication database in the Dallas office - and the CFO, pointing at the bills, wants to cancel the second Internet provider, arguing that it 'carried almost no traffic all year.'

Vulnerability found (the single point of failure + the fault-tolerance verdict):

Redundancy prescription + the resource cost accepted:

Enrichment - the reliability/scaling payoff of your fix:

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