GDA and Other Directory Service Components

GDA and Other Directory Service Components

The application uses XDS to make a Directory Service call. If the name to be accessed is a typed name, such as /.../C=US/O=OSF/OU=DCE/CN=SIG-DCE, then the query is passed to the Global Directory Service. If the name to be accessed is an untyped name, such as /.../cs.univ.edu/fs/usr/ziggy, or a partially typed name, such as /.../C=US/O=OSF/OU=DCE/fs/usr/snowpaws, then the query is passed to the Cell Directory Service. If the name is a local name, contained in the local CDS, then the query is handled by the local CDS server. If it is a name that resides in a foreign cell, it is passed to the GDA.

The GDA determines whether the foreign cell is registered in X.500 or DNS, based on the format of the name. It then contacts a GDS server or DNS server to find the foreign cell. Once the foreign cell is found, information about that cell is cached so that subsequent lookups of names in that cell do not require the involvement of a global directory server. Finally, the CDS server in the foreign cell is contacted to handle the query about the name.