This tree provides the mapping from DNS name space to the OSI name space and follows the recommendations of the RFC2247 (Using Domains in LDAP/X.500 Distinguished Names). For the purposes of SIMS, domain component tree is rooted at the root DNS domain suffix for that organization. In the example of Sun Microsystems, Inc., the secondary suffix would be dc=sun,dc=com. As in the case of the primary tree, this tree can have a single component suffix.
In the example below, we use two components suffix. The tree is rooted at dc=sun,dc=com and each node is composed of top, domain and labeledURIObject object classes. The directory entry for people container is shown below:
FIGURE D-2 SIMS Domain Component (Secondary) Directory Information Tree
It is very important the associations between the domain component tree (secondary) and the OSI tree (primary) be setup correctly for desired mail routing to occur. Figure above shows that the node dc=eng,dc=Sun,dc=COM points to the DN ou=eng,o=sun,c=us. SIMS looks for users in the eng.sun.com domain in the sub-tree ou=People,ou=eng,o=sun,c=us.