OSF DCE Application Development Guide--Introduction and Style Guide

Using the DCE Name Service
When applications have occasion to handle OIDs, they do so directly, since the numbers
do not change and should not be reused. However, for users’ convenience, CDS also
maintains a file (whose name is /opt/dcelocal/etc/cds_attributes) that lists string
equivalents for all the OIDs in use in a cell, in entries like the following:
1.3.22.1.1.4 RPC_Profile byte
This allows users to see RPC_Profile in output, rather than the mysterious 1.3.22.1.1.4.
Further details about the cds_attributes file and OIDs can be found in the .
Broadly speaking, the procedure you should follow to create new attributes on CDS
entries consists therefore of three steps:
1. Request and receive, from your locally designated authority, OIDs for the
attributes you intend to create.
2. Update the cds_attributes file with the new attributes’ OIDs and labels; that is, if
you want your application to be able to use string name representations for OIDs in
output.
3. Using XDS, write the routines to create, add, and access the attributes.
Non-NSI attributes on NSI entries can be very useful, even though you cannot access the
extra attributes through the name service routines but must use XDS instead.
5.5 Binding
In order to highlight the essentials of name lookup and storage and the management of
binding information, many details of DCE RPC operation are either greatly simplified in
the following descriptions or omitted altogether.
A binding is a package of information that describes how a client can contact and
communicate with a particular server. Although the underlying protocol that implements
the communication can be connectionless or connection-oriented, the relationship itself
is still expressed as a binding.
5.5.1 Importing and Exporting Bindings
The name service exists to store server binding information into the cell namespace, and
to retrieve that information for clients. Using NSI, servers export their binding
information to be stored under meaningful names, and clients import these bindings by
looking up those names. Thus, the locations of the servers can change, but clients can
continue to use the same names to get bindings to the servers. The following figure
shows how client and server use the name service.
Figure 5-3. Client and Server Use of the Name Service
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