DDoS mitigation layer
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.
Clarify5:30 left
Estimate5:30 planned
Design16:30 planned
Deep dive13:30 planned
Failure9:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.