Networking Study Portal

Key takeaways

• Count round trips, not milliseconds. Cross-region latency is physics and has a hard floor.
• TCP buys ordering and reliability with handshakes and head-of-line blocking; UDP is right when late data is worthless.
• Layer 4 routes on IP and port; layer 7 reads the request and can route on path, header, or cookie, and retry safely.
• Readiness checks that depend on shared downstreams turn degradations into fleet-wide outages.
• Prefer SSE for server-to-client streams; reserve WebSockets for genuinely bidirectional traffic.