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The Lightweight Directory Access Protocol (LDAP; ) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network. Directory services play an important role in developing intranet and Internet applications by allowing the sharing of information about users, systems, networks, services, and applications throughout the network.〔(【引用サイトリンク】title=Directory Services LDAP )〕 As examples, directory services may provide any organized set of records, often with a hierarchical structure, such as a corporate email directory. Similarly, a telephone directory is a list of subscribers with an address and a phone number. LDAP is specified in a series of Internet Engineering Task Force (IETF) Standard Track publications called Request for Comments (RFCs), using the description language ASN.1. The latest specification is Version 3, published as RFC 4511. For example, here is an LDAP search translated into plain English: "Search in the company email directory for all people located in Nashville whose name contains 'Jesse' that have an email address. Please return their full name, email, title, and description."〔(What is LDAP? ). Gracion.com. Retrieved on 2013-07-17.〕 A common usage of LDAP is to provide a ''single sign on'' where one password for a user is shared between many services, such as applying a company login code to web pages (so that staff log in only once to company computers, and then are automatically logged into the company intranet).〔 LDAP is based on a simpler subset of the standards contained within the X.500 standard. Because of this relationship, LDAP is sometimes called X.500-lite.〔(【引用サイトリンク】title=LDAP - Lightweight Directory Access Protocol )〕 ==History== Telecommunication companies' understanding of directory requirements were well developed after some 70 years of producing and managing telephone directories. These companies introduced the concept of directory services to information technology and computer networking, their input culminating in the comprehensive X.500 specification,〔The X.500 series - ITU-T Rec. X.500 to X.521〕 a suite of protocols produced by the International Telecommunication Union (ITU) in the 1980s. X.500 directory services were traditionally accessed via the X.500 Directory Access Protocol (DAP), which required the Open Systems Interconnection (OSI) protocol stack. LDAP was originally intended to be a lightweight alternative protocol for accessing X.500 directory services through the simpler (and now widespread) TCP/IP protocol stack. This model of directory access was borrowed from the DIXIE and Directory Assistance Service protocols. The protocol was originally created by Tim Howes of the University of Michigan, Steve Kille of Isode Limited, Colin Robbins of Nexor and Wengyik Yeong of Performance Systems International, circa 1993, as a successor〔(【引用サイトリンク】url=http://cybermatters.info/2013/04/09/prehistory-of-ldap/ )〕 to DIXIE and DAS. Mark Wahl of Critical Angle Inc., Tim Howes, and Steve Kille started work in 1996 on a new version of LDAP, LDAPv3, under the aegis of the Internet Engineering Task Force (IETF). LDAPv3, first published in 1997, superseded LDAPv2 and added support for extensibility, integrated the Simple Authentication and Security Layer, and better aligned the protocol to the 1993 edition of X.500. Further development of the LDAPv3 specifications themselves and of numerous extensions adding features to LDAPv3 has come through the IETF. In the early engineering stages of LDAP, it was known as ''Lightweight Directory Browsing Protocol'', or ''LDBP''. It was renamed with the expansion of the scope of the protocol beyond directory browsing and searching, to include directory update functions. It was given its ''Lightweight'' name because it was not as network intensive as its DAP predecessor and thus was more easily implemented over the Internet due to its relatively modest bandwidth usage. LDAP has influenced subsequent Internet protocols, including later versions of X.500, XML Enabled Directory (XED), Directory Service Markup Language (DSML), Service Provisioning Markup Language (SPML), and the Service Location Protocol (SLP). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lightweight Directory Access Protocol」の詳細全文を読む スポンサード リンク
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