OAM, OID and OIM:

 OAM: Oracle Access Manager:

OAM is the access manager, where we have abilities such as Single Sign On (SSO),Authentication

Authorization, Real time session management, Auditing and Policy Administration.

3 consoles in OAM i.e. Weblogic Console(/console), Enterprise Manager Console(/em), OAM Console (/oamconsole) in Oracle Access Manager.

Three main Consoles in OAM mainly

a) OAM Console : To register and manage system configurations, security elements, and policies.

b) WebLogic Console : Used by Administrators to Manage & Configure WebLogic Server (J2EE Server) on which OAM is deployed

c) FMW EM Console : Used by Administrators to Manage & Configure OAM Application

OID: Oracle Internet Directory:

OID is a LDAP implementation like Active Directory/AD. This is where users are stored for OAM.

Learn how to Install, Configure, Start/Stop OID, and how to Create a User/Group in OID. How to install Oracle WebLogic Server, how to install & configure IDM for OID server and how to verify WebLogic console and ODSM console.

OIM: Oracle Identity Manager:

OIM does life cycle management of a user or any similar entity. We may use OIM to provision the users. So basically it serves user management and reconciliation activities. If We have OIM, we can provision accounts to EBS or reconcile users from EBS to OIM.

when an employee is joined to your organization, you just create his user in  OIM and then reflect the necessary user/account definitions to the EBS .. FND_USER account, PERSON definitions etc.

When will OIM come into picture? Is this required for EBS?

Why does EBS require OID with OAM?

Reconciliation is for updating the Oracle Identity Manager. Provisioning is to put data from Oracle Identity Manager to another system.

Oracle Internet Directory (OID) : An LDAP directory server that stores its data in an Oracle database.

Oracle Identity Manager (OIM) : User Provisioning product acquired from Thor. It includes also reconciliation and administration tools. Reconciliation is the process by which operations, such as user creation, modification, or deletion, started on the target system are communicated to Oracle Identity Manager. The reconciliation process compares the entries in Oracle Identity Manager repository and the target system repository, determines the difference between the two repositories, and applies the latest changes to Oracle Identity Manager repository. In terms of data flow, provisioning provides the outward flow from the provisioning system (Oracle Identity Manager) by using a push model, in which the provisioning system indicates the changes to be made to the target system. Reconciliation is for updating the Oracle Identity Manager. Provisioning is to put data from Oracle Identity Manager to another system.

https://www.learn-it-with-examples.com/middleware/oracle-iam/oiam-architecture/oracle-identity-management-architecture-overview.html