Differences

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--- protocols:http [2026/07/01 11:07] – [Intro] v1ctor
+++ protocols:http [2026/07/01 14:08] (current) – [Intro] v1ctor
@@ Line 1: / Line 1: @@
 ====== HTTP ======
-==== Intro ====
+===== Intro =====
 HTTP can run in two modes:
@@ Line 13: / Line 13: @@
 Both have a start line, headers, an empty line and optional body.
 **Version** - the application doesn't usually care which protocol version is being used. The web-server translates the protocol details into standard request before passing it to the application.
-==== HTTP Request Message ====
+The version is **negotiated** during TLS handshake. The browser advertises the application protocols it supports using TLS extension called ALPN.
+There is no TLS handshake for HTTP, so the browser simply starts with **HTTP/1.1**.
+**HTTP/3**\\
+HTTP/3 runs on top of the QUIC (Quick UDP). The main idea that we eliminate two handshaks that were needed in HTTPs (TCP + TLS).
+In QUIC TLS handshake is absorbed into the initial setup handshake. HTTP/3 does not run TLS "on top" of QUIC. Instead, **TLS 1.3** is built into the QUIC protocol itself.
+QUIC mitigates HOL (Head of Line) problem by treating each stream within a single connection independently. If one particular frame is lost, QUIC will handle it separately without blocking the rest of the streams.
+===== HTTP Request Message =====
 First line in the Request Message is called a **request** line. The subsequent lines are called **headers** line.