Active Directory - Windows Server Directory Service

Active Directory -commonly known as AD

Active Directory is a directory service by Microsoft for windows Domain Networks, It is Included in most of the windows server operating servers.

we can say its a kind of database that keeps track of all the user accounts of your organization and passwords. It allows to store all your user accounts and passwords in one protected location, that's improving organization's security.

These are the some terms you should know about when you deal with Active Directory

AD - (Active Directory)

DCO - (Domain Controller)

LDAP - (Lightweight Directory Access Protocol)

OU - (Organizational Units)

DNS - (Domain Name System)

RPC- (Remote Procedure Call)

Active Directory Domain Controller - 

Domain controller authenticates and authorizes all users and computers in a Windows domain type network
and assign security policies for all the computers 

Database Used by Active Directory - 

Active Directory uses  "Extensible Storage Engine" (ESE), also known as JET Blue, is an ISAM (Indexed Sequential Access Method) provided by Microsoft. 

Trusting

To allow users in one domain to access resources in another, Active Directory uses trusts.

Architecture of Active Directory on a Windows Server Network

Source : Active Directory