Module 2
How data moves through the internet: DNS resolution, CDNs, load balancing, API design patterns, and real-time communication protocols.
How DNS works end-to-end: recursive resolvers, authoritative servers, caching, TTLs, and DNS-based load balancing strategies.
How CDNs work: edge caching, PoPs, cache invalidation, push vs pull CDNs, and when to use them in system design.
Layer 4 vs Layer 7 load balancing, algorithms (round-robin, least connections, consistent hashing), health checks, and sticky sessions.
What a reverse proxy does, how it differs from a load balancer, and common use cases: SSL termination, compression, rate limiting.
Compare REST, GraphQL, and gRPC: when to use each, versioning strategies, pagination, and API design best practices.
Real-time communication protocols: WebSocket full-duplex connections vs SSE one-way streams, connection management, and scaling challenges.
When WebSockets are overkill: understanding short polling, long polling, and how to choose the right approach for your latency requirements.