Federated Naming Service Programming Guide

Initial Context Bindings

Resolution of a name in XFN always begins with some context. XFN defines an initial context as a starting point for name resolution. The initial context contains bindings that allow the client application to (eventually) name any object in the enterprise namespace. Figure 1-4 shows the same naming system as the one shown in Figure 1-3, except that the initial context bindings are shaded and shown in italics.

Figure 1-4 Example of Enterprise Bindings in the Initial Context

The initial context has a flat namespace for namespace identifiers. The bindings of these namespace identifiers are summarized in Table 1-2. The categories of bindings are:

User-related bindings
Host-related bindings
"Shorthand" bindings

In Table 1-2, the user to which the bindings are related is denoted by U, and the host to which the bindings are related is denoted by H. Not all of these names need to appear in all initial contexts. For example, when a program is invoked by the superuser, none of the user-related bindings appears in the initial context.

Table 1-2 Initial Context Bindings for Naming Within the Enterprise


Namespace Identifier	Binding
`myself` `_myself` `thisuser`	U's user context
`myens` `_myens`	The enterprise root of U
`myorgunit` `_myorgunit`	U's distinguished organizational unit context. For NIS+, the distinguished organizational unit is U's NIS+ home domain. For NIS and files, it is the current domain and system, respectively.
`thishost` `_thishost`	H's host context
`thisens` `_thisens`	The enterprise root of H
`thisorgunit` `_thisorgunit`	H's distinguished organizational unit context. For NIS+, the distinguished organizational unit is H's NIS+ home domain. For NIS and files, it is the current domain and system, respectively.
`user` `_user`	The context in which users in the same organizational unit as H are named
`host` `_host`	The context in which hosts in the same organizational unit as H are named
`org` `orgunit` `_orgunit`	The root context of the organizational unit namespace in H's enterprise. For NIS+, this corresponds to the NIS+ root domain. For NIS and files, it is the current domain and system, respectively.
`site` `_site`	The root context of the site namespace at the top organizational unit if the site namespace has been configured
`...` `/...`	Global context for resolving DNS or X.500 names
`_dns`	Global context for resolving DNS names
`_x500`	Global context for resolving X.500 names