Networking

12 posts in this domain.

How does League of Legends keep ten players in sync at low latency? Ten strangers on ten different ISPs share one world that has to feel instantaneous. The trick is that nobody's screen shows exactly the same thing — and that's the feature, not the bug. May 1, 2026 · intermediate
What is TCP? IP delivers packets best-effort — they can vanish, duplicate, or arrive out of order. Almost every program wants a clean stream of bytes instead. TCP is the layer that turns one into the other. Apr 30, 2026 · intro
What is TLS? TCP gives you a reliable byte stream that every router along the path can read and modify. TLS is the layer that wraps that stream so you get confidentiality, integrity, and proof of who's on the other end. Apr 30, 2026 · intro
Why does CORS exist? CORS isn't there to keep you out of an API — it's there to stop a webpage you're visiting from quietly using your logged-in cookies on a different site. The whole design only makes sense once you see that. Apr 29, 2026 · intro
Why is DNS hierarchical? DNS could have been a giant flat lookup table — one machine somewhere mapping every name in the world to an IP. It isn't, and the reason is less about technology than about who gets to be in charge of what. Apr 29, 2026 · intermediate
Why retry with exponential backoff — and why jitter? Retrying on failure sounds simple until you ship it at scale. Hammer the server and you make outages worse; back off but synchronize, and you accidentally rebuild the herd. Backoff is the timing rule; jitter is the part that keeps it from biting itself. Apr 29, 2026 · intro
Why does HTTPS need certificates if encryption already works? Encryption alone gets you a private channel — to whoever's on the other end. Certificates are how the browser decides that 'whoever' is the bank you meant to reach, not someone sitting in the middle pretending to be. Apr 29, 2026 · intro
Why does QUIC exist when TCP already works? TCP works fine — until you're on a flaky phone connection, juggling a dozen multiplexed streams, and one lost packet stalls all of them. QUIC is the protocol designed around that specific frustration. Apr 29, 2026 · intermediate
Why does TCP have congestion control? The internet didn't always have it. Once, in 1986, it nearly fell over. The fix wasn't a protocol change — it was endpoints learning to back off. Apr 29, 2026 · intermediate
Why do CDNs exist when we already have fast servers? Your origin server can be the fastest box on Earth and your users in São Paulo will still hate it. CDNs exist because the speed of light, not your CPU, is the bottleneck. Apr 29, 2026 · intro
Why GPU clusters need NVLink and InfiniBand Training a frontier model means thousands of GPUs taking the same step at the same time. Ethernet wasn't built for that, and PCIe gave up a long time ago. Apr 29, 2026 · intermediate
Why do LLM responses stream? It's not for show. The model literally generates one token at a time, and forcing it to buffer the full answer before sending would make every chat app feel broken. Streaming is the network shape of an autoregressive process. Apr 29, 2026 · intro