\subsection{Relationship Element}
\label{sec:relationship}

The \xmlelement{relationship} element designates the type of
relationship an alternate contact has with the presentity.  This element
is provided only if the tuple refers to somebody other than the
presentity.  Relationship values include ``family'', ``associate''
(e.g., for a colleague), ``assistant'', ``supervisor''.  Other free-text
values and additional IANA-registered values (Section~\ref{sec:iana})
can be used as well.

The \xmlelement{contact} element for tuples labeled with a relationship
can contain either a communication URI such as ``im'', ``sip''/``sips'',
``h323'', ``tel'' or ``mailto'', or a presence URI, such as ``pres'' or
``sip''. 
