AP CSP Day 19: Https Encryption

Big Idea 4: Computing Systems & Networks
Cycle 1 • Day 19 Practice • Medium Difficulty
Focus: Fault Tolerance & Redundancy

Practice Question

In a network, four devices (A, B, C, D) are connected: A to B, A to C, B to D, and C to D. If the connection between A and B fails, can device A still communicate with device D?

Why This Answer?

The network has redundant paths. Although the A-B connection fails, A can still reach D through the alternative path A → C → D. This is fault tolerance through redundancy — multiple paths ensure communication continues despite individual failures.

Why Not the Others?

A) The existence of an alternative path (A-C-B) means communication is still possible. B is correct. C) No repair is needed because the alternate path through C works immediately. B) Device D remains connected to C and B; it is not isolated.

Common Mistake
Watch Out!

Students only consider the most direct path and forget to check for alternative routes. In fault tolerance questions, always trace ALL possible paths.

AP Exam Tip

For network fault tolerance questions, draw the diagram and systematically trace every possible path between the two endpoints. If at least one path exists, communication is possible.

Keep Practicing!

Consistent daily practice is the key to AP CSP success.

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