Atomic names and reference addresses may also be resolved relative to one or more namespaces. By default, FNS provides six namespaces: org (for organization), site, host, user, service, and fs (for files).
FNS policies are used to determine how names associated with namespaces relate to each other. For example; a user is named sergei in the user namespace and is identified as /user/sergei. A calendar application is named in the service namespace and is identified as /service/calendar. With this system, you can then identify Sergei's calendar service as: /user/sergei/service/calendar. (See "Introduction to FNS and XFN Policies" for more information on namespaces and how they are used.)
If an application is expecting you to type a user name, the application can include the namespace identifier user/ in front of names that you enter. If the application needs to name one of the user's services, such as the user's default fax machine, it can append the service namespace and the name of the service (/service/fax), to the input supplied. Hence, a fax tool might take as input the user name jacques and then compose the full name user/jacques/service/fax for the default fax of the user jacques. Similarly, to access a person's calendar, you just need to type the person's user name. The application takes the input, raj, and uses it to construct the composite name, in this case, user/raj/service/calendar.