Networking & Protocols
HTTP versions: free-recall review
Retrieval beats re-reading. For each prompt, say or write a full answer from memory before you open the model answer — the effort of recall is what makes the protocol mechanics stick.
Reconstruct the unit’s spine — why each HTTP version exists, where head-of-line blocking lives at each layer, how QUIC and QPACK preserve stream independence, connection migration, and the operational signals — without looking back at the lessons.
- 01Why did HTTP/2 and HTTP/3 get invented if HTTP/1.1 already worked?
- 02Explain the two layers of head-of-line blocking and which version fixes each.
- 03Why does HTTP/3 use QPACK instead of HPACK, and how does QPACK preserve stream independence?
- 04What is QUIC connection migration and why does it matter for mobile?
- 05Why is HTTP/2 Server Push dead, and what replaced it?
- 06How is HTTP/3 discovered and selected, and what production signal tells you UDP is being blocked?
If you could reconstruct each answer from memory, you hold the unit’s spine: HTTP/1.1 parallelises with many connections, HTTP/2 multiplexes streams and kills application-layer HOL blocking but inherits transport-layer HOL blocking from TCP, and HTTP/3 on QUIC isolates loss per stream, uses QPACK to keep stream independence at the header layer, and migrates across IP changes. Server Push is dead in favour of 103 Early Hints, and the production health signal is ALPN distribution plus h3-fallback by ASN.