Abstract
With the vast advances of the Internet, increasing information is placed on the Internet and can be shared with others. The management of the network resources is getting more and more important. Directories can provide an efficiency and convenient way to store and manage information, and enable a new kind of applications, called directory services. To unify the access to different directories, IETF proposes the Lightweight Directory Access Protocol (LDAP). In this thesis, we study LDAP and discuss how to support efficient directory services.We first study the differences between a directory and a database, and compare the performance of LDAP and SQL. The features compared include the search and add efficiency and cache effects. Next, we study LDAP in distributed environments. First, we examine the problem of data consistency in LDAP and propose our solution. We then discuss how to build a LDAP virtual server, which uses multiple real machines to form a cluster to balance the load and improve the performance.