Essential networking for backend/AI-engineer interviews — Google, Microsoft, Amazon.
Tier 1 — master these: TCP, HTTP, HTTPS/TLS, DNS, IP Addressing, Load Balancing, Reverse Proxy, Authentication & Authorization, Connection Pooling, Timeouts/Retries/Backoff, Message Queues, Microservices Communication.
Tier 2 — strong understanding: Subnetting/CIDR, NAT, UDP, HTTP/2 vs HTTP/3, Cookies & Sessions, CORS, CDN, WebSockets, Rate Limiting, Circuit Breaker, REST vs gRPC, Network Security, VPC & Subnets, Distributed Tracing.
Tier 3 — supporting knowledge: Service Discovery, and everything in the "learn later" bucket (BGP, OSPF, RIP, deep Ethernet/ARP/ICMP internals, physical layer, deep QUIC internals) — useful context, rarely the crux of an interview question.