You can use .../rootdomain/ to identify an enterprise root where:
The initial three dots (...) are an atomic name indicating the global context (see "Policies for the Global Namespace" for a description of the global context).
rootdomain/ is the enterprise root domain. For example, doc.com/.
Thus, .../doc.com/ identifies the enterprise root of a company whose root domain is doc.com. In this example, the context for naming sites associated with the enterprise root is .../doc.com/site/ such as .../doc.com/site/alameda or .../doc.com/site/alameda.bldg5.
You can only use the .../rootdomain format if you have set up the global binding in DNS.