Code Room
System designHard
Question
Design a DDoS-mitigation layer protecting a global platform from volumetric (L3/L4 floods), protocol, and application-layer (L7) attacks, capable of absorbing multi-terabit attacks while keeping p99 latency for legitimate users under 50ms. It must distinguish attack traffic from flash-crowd legitimate spikes, automatically engage scrubbing, and not blackhole real users. Cover the network architecture, detection, the mitigation pipeline, and the legitimate-vs-attack discrimination trade-off.
What a strong answer looks like
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.
Learn the concepts
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