OID allows Oracle DBAs to centralize name management, instead of us all having our out-of-date local connection data in our many separate tnsnames.ora files (tnsnames can still be used as a fallback if needed).

Example contents of sqlnet.ora:

#SQLNET.AUTHENTICATION_SERVICES= (NTS)  
NAMES.DIRECTORY_PATH=(LDAP,TNSNAMES)

Example contents of ldap.ora:

DIRECTORY_SERVERS=(oidsrv01:3060:3131,oidsrv02:3060:3131)  
DEFAULT_ADMIN_CONTEXT = "dc=oracle,dc=local"  
DIRECTORY_SERVER_TYPE = OID

In this example, oidsrv01 and oidsrv02 (and more as needed) have to be replaced by actual OID server names, of course.