19th Implementation Draft

Overview

Feature	code	details
Version Negotiation	V	A version negotiation response is elicited and acted on
Handshake	H	The handshake completes successfully
Stream Data	D	Stream data is being exchanged and ACK'ed
Connection Close	C	The connection close procedure completes w/a zero error code
Resumption	R	Connection is established using TLS Resume Ticket
0-RTT	Z	0-RTT data is being sent and acted on
Stateless Retry	S	A handshake that includes a Retry packet completes successfully
Quantum Ready	Q	A handshake including the quantum readiness test TP completed successfully (see Quantum Readiness test on Wiki)

(Note that H3 and Key Update are not "optional" in the spec, but many implementations have chosen to defer them)

Feature	code	details
Server CID change	M	A server offers new CIDs to a client in advance. Upon some events, the client starts using a new server CID
NAT Rebinding	B	A client's port changes. The client sends packets without noticing the change
Address Mobility	A	A server offers new CIDs to a client in advance. The client moves to a new address(/port). The client sends path challenges from the new address(/port) with a new server CID. The server sends path responses on any path
Key Update	U	One endpoint can update keys and its peer responds correctly
H3	3	An H3 transaction succeeded
Spin	P	A connection with the spin succeeds and the bit is spinning
ECN	E	Set ECT(0) on outgoing packets and verify that ACK frames with ECN information are received. (Note: test can fail if path bleaches ECN)

Feature	code	details
Throughput	T	Download objects named 5000000 and 10000000 on separate connections over both HTTP/2 and HTTP/3 (0.9 if H3 not available). Overall transfer time should be no worse than 10% slower than HTTP/2.

Feature	code	details
Dynamic Tables	d	QPACK Dynamic Tables
Push	p	PUSH successfully delivered