Connection preface
01Both peers establish HTTP/2 state before exchanging ordinary requests.
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 3.4 ↗
RFC 9113 · § 3.4EXAMPLE
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03
Synchronize settings
The server sends SETTINGS and peers acknowledge settings.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
RFC 7540 priorities and UpgradeRFC 9113 Appendix B
The older priority scheme and HTTP/1.1 Upgrade bootstrap are deprecated; the revision also incorporates TLS 1.3 guidance.
Read the updated RFC section ↗TLS connections negotiate h2 using ALPN.
- TLS connections negotiate h2 using ALPN.
- The client preface starts with a fixed 24-octet sequence followed by SETTINGS; the server starts with SETTINGS.
- Settings apply per connection and are acknowledged.
Examples are illustrative. Consult the linked RFC and its errata for implementation details.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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