OSF DCE Administration Guide--Core Components

OSF DCE Administration Guide—Core Components
topology.
Figure 11-1. Cell and Global Naming Environments
GDS
Cell 2
CDS
Cell 1
CDS
DNS is a widely used existing global name service for which DCE offers support. Many
networks currently use DNS primarily as a name service for Internet host names.
Although DNS is not a part of the DCE technology offering, the directory service
contains support for cells to interoperate through DNS.
The GDA is the DCE component that makes cell interoperation possible. The GDA
enables CDS to access a name in another cell through one of the global naming
environments (GDS or DNS), or through the CDS of the parent cell, if the cell is part of a
hierarchical cell configuration. The GDA is an independent process that can exist on a
system separate from a CDS server, although by default the DCE configuration script
configures the GDA on the same machine as a CDS server. CDS needs to be able to
contact at least one GDA to participate in the global naming environment.
Figure 11-2 shows how the GDA helps CDS access names outside of a cell. When CDS
determines that a name is not in its own cell, it passes the name to a GDA, which
searches the appropriate naming environment (CDS, GDS, or DNS) for more information
about the name. The GDA returns information that enables the original CDS server to
contact the CDS server in whose cell the name resides. The GDA can help CDS find
names in a cell that is registered in DNS (Scenario A), a cell that is registered in GDS
(Scenario B), or a cell that is registered in the originating cell’s parent cell (not shown).
The GDA decides which name service to use based on the syntax of the name. Section
11.5 describes name syntaxes in detail.
Figure 11-2. Interaction of CDSs, GDAs, and Global Directory Services
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