HTTP/2 リファレンス
リファレンス 用 HTTP/2: multiplexing, stream prioritization, HPACK ヘッダー compression, および サーバー push.
Core Improvements
HTTP/2 (RFC 9113) multiplexes multiple streams over a single TCP connection, eliminating head-of-line blocking. HPACK compresses headers using a static and dynamic table, reducing overhead significantly. Binary framing replaces text-based framing for efficient parsing. Server push allows preemptively sending resources, though it is largely deprecated in favor of Link preload. Streams can be prioritized by the client.
- multiplexing
- Multiple streams per connection
- HPACK
- Header compression
- binary
- Binary framing
no HOL blockingstatic + dynamic tableefficient parsingAdoption and Issues
HTTP/2 is widely deployed, negotiated via ALPN in TLS or via h2c upgrade for plaintext. The single TCP connection means packet loss affects all streams (TCP-level HOL blocking). Stream prioritization has been problematic in practice; many servers ignore client priorities. Server push is deprecated due to misuse and cache inefficiency. These issues motivated HTTP/3 over QUIC. Most browsers only support HTTP/2 over TLS.
- ALPN
- TLS negotiation
- TCP HOL
- Packet loss blocks all
- push deprecated
- Misuse issues
h2 protocol IDall streams stalluse preload instead