FNS defines naming policies so that users and applications can depend on and use the shared namespace.
Within an enterprise, there are namespaces for organizational units, sites, hosts, users, files and services, referred to by the names orgunit, site, host, user, fs (for file system), and service. These namespaces can also be named by preceding each name with an underscore (_). For example, host and _host are considered identical.
Table 20-1 summarizes the FNS policies for enterprise-level namespaces.
Table 20-1 FNS Policy Summary
Context Type |
Subordinate Contexts |
Parent Contexts |
---|---|---|
orgunit _orgunit |
site user host fs service |
enterprise root |
site _site |
user host fs service |
enterprise root orgunit |
user _user |
service fs |
enterprise root orgunit |
host _host |
service fs |
enterprise root orgunit |
service _service |
Printer and other applications |
enterprise root orgunit site user host |
fs _fs(file system) |
(none) |
enterprise rootorgunit site user host |
The binding of an FNS orgunit is determined by the underlying naming service:
Under NIS+, an organizational unit corresponds to an NIS+ domain or subdomain. For example, assume that the NIS+ root domain is doc.com. and sales is a subdomain of doc.com. Then, the FNS names org/sales.doc.com. and org/sales both refer to the organizational unit corresponding to the NIS+ domain sales.doc.com. (Note the trailing dot in sales.doc.com.which is required for fully qualified NIS+ names.)
Under NIS, an organizational unit is the NIS domain which is always identified by the FNS name org// or org/domainname where domainname is a fully qualified domain name such as doc.com.. Under NIS, there is no hierarchy in organizational unit names.
Under a files-based naming system, the organizational unit is the system which is always identified by the FNS name org//.
The types of objects that may be named relative to an organizational unit name are: user, host, service, fs, and site. For example:
org/sales/site/conference1.bldg-6 names a conference room conference1 located in building #6 of the site associated with the organizational unit sales. In this example, if org/sales corresponds to sales.doc.com., another way to name this object would be: org/sales.doc.com./site/conference1.bldg-6 (note the trailing dot in sales.doc.com.)
org/finance/user/mjones names a user mjones in the organizational unit finance.
org/finance/host/inmail names a machine inmail belonging to the organizational unit finance.
org/accounts.finance/fs/pub/reports/FY92-124 names a file pub/reports/FY92-124 belonging to the organizational unit accounts.finance.
org/accounts.finance/service/calendar names the calendar service of the organizational unit accounts.finance. This might manage the meeting schedules of the organizational unit.
Site names are created as needed. The types of objects that may be named relative to a site name are: user, host, service and fs. For example:
site/alameda/user/mjones names a user mjones at the site alameda.
site/alameda/host/sirius names a machine sirius at the site alameda.
site/alameda/service/printer/Sparc-2 names the printer Sparc-2 at the site alameda.
site/alameda/fs/usr/dist names a file directory usr/dist available in the site alameda.
User names correspond to names in the corresponding passwd table in NIS+, the passwd map in NIS, or the /etc/passwd file under files. A user's file context is obtained from his or her passwd entry.
The types of objects that may be named relative to a user name are: service, and fs. For example:
user/chou/service/fax names the fax service of the user chou.
user/esperanza/fs/projects/conf96.doc names the file conf96.doc in the projects subdirectory of the user esperanza's file system.
Host names correspond to names in the corresponding hosts table in NIS+, the hosts map in NIS, or the /etc/hosts file under files. The host's file context corresponds to the files systems exported by the host.
The types of objects that may be named relative to a host name are: service, and fs. For example:
host/smtp-1/service/mailbox names the mailbox service associated with the machine smtp-1.
host/deneb/fs/etc/.cshrc names the file .cshrc in the /etc directory on the host deneb.
Service names correspond to, and are determined by, service applications. The service context must be named relative to an organization, user, host, or site context. For example:
org//service/printer names the organization's printer service.
host/deneb/service/printer names the printer service associated with the machine deneb.
host/deneb/service/printer/Sparc-2 names the printer associated with the machine deneb.
user/charlie/service/calendar names the user charlie's calendar service.
site/conf_pine.bldg-7.alameda/service/calendar names the calendar service for the conf_pine conference room in Building 7 at the Alameda site.
File system names correspond to file names. For example: