The directory service whichis loaded onto Windows 2000.It is possibleto managethe informationof the hardwarere source of the server,the clientand the printer etc. which exist with respect to network and attributeand accessright etc. of the user which uses those monistically. So far,Windows NT did at the unit which is called the managementof these resources "domain ", but whenplural domains are used mutually, if one by one mutually relationship of reliance had to be formed,, tothe managementof large-scale network did not face. If Active Directory is utilized,providinglayered structure in domain, and the resource because it is possible, to manage,scale of network becoming large, it can manage easily.