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System Design Card 433 — CDN and Media Delivery / Structure

CDN And Media Delivery — BASIC step map

Concern

Static and media-heavy workloads often need edge distribution rather than central-origin delivery for acceptable performance. Image-serving, file download, and streaming content systems depend heavily on caching at the edge.

Your first instinct is usually close — but not close enough.

What Structure means for this concern

In BASIC, the Structure step is where you turn the chosen trade-offs into a clear high-level architecture and request flow. For CDN and Media Delivery, that means the candidate should make this concern visible at the right moment instead of bolting it on at the end.

Design move

A good move is to make the plan visible before full execution. Tie the concern back to the user flow, the workload, and the dominant trade-off. That keeps the design grounded and makes it easier for the interviewer to follow why a cache, queue, replica, partition, or rate limiter is actually necessary.

Common miss

The miss is treating global content delivery like ordinary API traffic. BASIC helps because the staged flow keeps this concern proportional to the prompt and connected to the rest of the architecture.

BASIC prompt

“When I reach the Structure stage, how does CDN and Media Delivery change the architecture, the trade-offs, or the review checklist?”

Common trap
Many candidates treat Structure and Implement as the same step. They start writing code while still figuring out the approach. The result is code that wanders — corrections mid-loop, variable names that stop making sense, backtracking that wastes time. Separate the plan from the execution.

References

S9 S14 S15

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