\section{The Meaning of ``open'' and ``closed''}
\label{sec:open}

PIDF describes the basic status values of ``open'' or ``closed'' only as
``have meanings of general availability for other communications
means''.  We define ``closed'' in our context as meaning that
communication to the contact address will in all likelihood not succeed,
is undesired or will not reach the intended party.  (For example, a
presentity may include a hotel phone number as a contact.  After
check-out, the phone number will still ring, but reach the chambermaid
or the next guest.  Thus, it would be declared ``closed''.) For ``pres''
contacts, ``closed'' means that no presence status information is
available.

\motivation{The interpretation of ``closed'' was chosen since there is
no other status value to indicate that a communications address is not
reachable.  Omitting the \xmlelement{contact} element does not work
since it would confuse watchers that have not previously seen an
``open'' status for the same contact address.}

