Each calendar in the database is identified by a unique calendar ID (calid). The following calid syntax has three parts:
The three parts are:
A user ID that is unique for the domain in this Calendar Server instance.
The name of the user’s domain.
With no hosted domains, the domain part is optional since there is no ambiguity about which domain the user is in.
With hosted domains, if the domain part is not specified, then Calendar Server uses the value specified in the ics.conf parameter service.defaultdomain for the domain. If the user is not in the default domain, the domain part must be specified.
An optional calendar name that is unique to the specific user. Although an owner has only one default calendar, it is possible to have other calendars for various purposes. Each of these non-default calendars is distinguished by its calendar name. For example, if user John Doe has a uid jdoe, his default calendar might be email@example.com. An auxiliary calendar he uses to keep track of baseball games for the Little League team he coaches might be identified with the following calid: firstname.lastname@example.org:baseball.