Streams, Packets, and Protocols

As C++ networking shifts from callbacks to coroutines, the distance between readable code and wire‑speed performance has never been smaller-or more treacherous. This book is for seasoned C++ engineers, protocol authors, and performance‑minded systems developers who need to ship reliable, low‑latency services. It bridges elegant abstractions with gritty realities: timeouts, partial I/O, head‑of‑line blocking, MTUs, TLS handshakes, and cross‑platform quirks from Linux epoll to Windows IOCP.

Coroutines form the spine: master suspension, cancellation, and back‑pressure, then compose safe asynchronous flows. Apply C++23 span, byte, endian, chrono, and PMR to buffers and deadlines. Compare reactor/proactor loops; design executors and timers. Dive into buffer sequences, scatter/gather, zero‑copy; IP, sockets, MTU/MSS; TCP framing and tuning; UDP batching, multicast, and a pragmatic QUIC tour. Put it together with Boost.Asio/Networking TS, TLS 1.3 on OpenSSL 3, io_uring and IOCP, and resilient DNS with Happy Eyeballs.

Prerequisites: strong modern C++ (C++20/23), familiarity with OS concurrency and basic networking. Examples favor idiomatic, allocation‑aware C++ and portable Asio‑style APIs. The emphasis is production: determinism under load, tail‑latency discipline, robust teardown, observability, and build hygiene with sanitizers, LTO, and PGO.