diff --git a/draft-ietf-quic-http.md b/draft-ietf-quic-http.md index d9e19ebc61..e274873c60 100644 --- a/draft-ietf-quic-http.md +++ b/draft-ietf-quic-http.md @@ -319,7 +319,9 @@ connection to that server as being authoritative for all origins with the A client MAY attempt access to a resource with an "https" URI by resolving the host identifier to an IP address, establishing a QUIC connection to that address on the indicated port, and sending an HTTP/3 request message targeting the URI -to the server over that secured connection. +to the server over that secured connection. Unless some other mechanism is used +to select HTTP/3, the token "h3" is used in the Application Layer Protocol +Negotiation (ALPN; see {{!RFC7301}}) extension during the TLS handshake. Connectivity problems (e.g., blocking UDP) can result in QUIC connection establishment failure; clients SHOULD attempt to use TCP-based versions of HTTP @@ -333,8 +335,7 @@ default port associated with the scheme. An HTTP origin advertises the availability of an equivalent HTTP/3 endpoint via the Alt-Svc HTTP response header field or the HTTP/2 ALTSVC frame ({{!ALTSVC}}), -using the Application Layer Protocol Negotiation (ALPN; see {{!RFC7301}}) token -defined in {{connection-establishment}}. +using the "h3" ALPN token. For example, an origin could indicate in an HTTP response that HTTP/3 was available on UDP port 50781 at the same hostname by including the following