diff --git a/draft-ietf-httpbis-alt-svc.xml b/draft-ietf-httpbis-alt-svc.xml
index e5f6c72f7..b423228e3 100755
--- a/draft-ietf-httpbis-alt-svc.xml
+++ b/draft-ietf-httpbis-alt-svc.xml
@@ -372,13 +372,24 @@ uri-host = <uri-host, see >
-Alt-Svc = 1#( alternative *( OWS ";" OWS parameter ) )
+Alt-Svc = 1#alt-value
+alt-value = clear / ( alternative *( OWS ";" OWS parameter ) )
+clear = "clear"; "clear", case-sensitive
alternative = protocol-id "=" alt-authority
protocol-id = token ; percent-encoded ALPN protocol name
alt-authority = quoted-string ; containing [ uri-host ] ":" port
parameter = token "=" ( token / quoted-string )
+
+ The field value consists of a list of values, each of which indicating one
+ alternative service or being the keyword "clear".
+
+
+ Any field value containing the special value "clear" indicates that the
+ origin requests all alternatives for that origin to be invalidated (including
+ those received in the same response).
+
ALPN protocol names are octet sequences with no
additional constraints on format.
@@ -457,6 +468,10 @@ Alt-Svc: h2="new.example.org:80"
Alt-Svc: h2c=":8000", h2=":443"
+
+ When multiple values are present, the order of the values reflects the server's
+ preference (with the first value being the most preferred alternative).
+
The value(s) advertised by Alt-Svc can be used by clients to open a new
connection to an alternative service. Subsequent requests can start using this new connection
@@ -1095,6 +1110,10 @@ Alt-Used: alternate.example.net
+
+ Alt-Svc alternative cache invalidation
+ ().
+
Unexpected Alt-Svc frames
().