AP CSP 4.1 Exercise 1: Packet Journey - The Photo That Arrived in Pieces

Big Idea 4 · Topic 4.1 · Exercise 1

Packet Journey - The Photo That Arrived in Pieces

25 minutes

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Q1 · 3 points on the handout

The link between R4 and the phone has a bandwidth of 8 million bits per second, and the photo is 2 MB (about 16 million bits). What is the FASTEST the photo could cross that link, and why might the real transfer take longer? Use the CED's definition of bandwidth.

Q2 · 3 points on the handout

The laptop and the phone were built by different companies and run different operating systems, yet their packets interoperated perfectly. Explain how, using the CED definitions of protocol and of open protocols.

Q3 · 2 points on the handout

ENRICHMENT: If this had been a live video call instead of a photo, re-sending #3 two seconds later would be useless - that moment of the call has already passed. Of the protocols named in EK CSN-1.C.4, which fits each job (photo vs. live call), and what does each choice trade away?

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