[Ietf-calsify] Section 4.6.6 Alarm Component: Restriction over the value of the ACTION property

[Bernard Desruisseaux]

According to section 4.8.6.1 Action of RFC 2445, the ACTION property
can take the following values:

 > actionvalue        = "AUDIO" / "DISPLAY" / "EMAIL" / "PROCEDURE"
 >                    / iana-token / x-name

On the other hand, section 4.6.6 Alarm Component restricts the values
that the ACTION property can take when used in a VALARM component to
the following: AUDIO, DISPLAY, EMAIL, and PROCEDURE. Check the last
sentence of the following paragraph:

 > The "ACTION" property is used within the "VALARM" calendar component
 > to specify the type of action invoked when the alarm is triggered.
 > The "VALARM" properties provide enough information for a specific
 > action to be invoked. It is typically the responsibility of a
 > "Calendar User Agent" (CUA) to deliver the alarm in the specified
 > fashion. An "ACTION" property value of AUDIO specifies an alarm that
 > causes a sound to be played to alert the user; DISPLAY specifies an
 > alarm that causes a text message to be displayed to the user; EMAIL
 > specifies an alarm that causes an electronic email message to be
 > delivered to one or more email addresses; and PROCEDURE specifies an
 > alarm that causes a procedure to be executed. The "ACTION" property
 > MUST specify one and only one of these values.

In my opinion, one should be allowed to specify an ACTION property
with a "iana-token" or "x-name" value in a VALARM component.

A vendor might want to use "x-name" values (or register iana-token)
for alarms that should be delivered by SMS, XMPP, Fax, Voice, etc.

Cheers,
Bernard