Which parts of HTTP/2 are stateful?

Question

Unlike the original stateless HTTP/1, HTTP/2 has many stateful components.

These parts of HTTP/2 are stateful:

• Header blocks refer to a stateful unsigned 31-bit integer called a stream identifier
• Frames also reference the same stateful stream identifier
• opportunistic encryption also depends on state since TLS is stateful

Are there any other parts of HTTP/2 that are stateful?

Answer 1

HTTP 2 adds many stateful components to the HTTP corpus.

• Streams use a stateful unsigned 31-bit integer called a "stream identifier".
• Header blocks are used to statefully establish the stream identifier.
• Frames are stateful.
• Header compression is stateful.
• Opportunistic encryption is stateful.

The following are stateful components carried from previous HTTP additions which are still stateful in HTTP 2.

• Cookies are stateful.
• HTTPS is stateful.
• HTTP caching is stateful. (See also RFC 7234.)
• HTTP defined authentication is stateful. (See also RFC 7235)
• Web Sockets are stateful and use a stateful "Sec-WebSocket-Key" HTTP header.
• Web Storage, although not HTTP, is also stateful.