High Level Design
Load balancers, routing algorithms, Layer 4 vs Layer 7 balancing, health checks, and how traffic flows through a real system.
How consistent hashing solves the massive-rehashing problem in distributed systems — hash rings, virtual nodes, load imbalance, and real-world use cases.
End-to-end design of a production-grade load balancer — control and data planes, health checking, session persistence, SSL termination, and high-availability with active-active failover.