The master domain name is top level domain name. The Domain Master Browser is necessary on a routed TCP/IP network, that is, when a Windows domain spans more than one TCP/IP network.............

What is the RID Master role? The RID Master is one of the operations master roles that exist in each domain in a forest. It controls the sequence number for the domain controllers within a domain. It provides a unique sequence of RIDs to each domain controller in a domain. When a domain controller creates a new object, the object is assigned a unique security ID consisting of a combination of a domain SID and a RID. The domain SID is a constant ID, whereas the RID is assigned to each object by the domain controller. The domain controller receives the RIDs from the RID Master. When the domain controller has used all the RIDs provided by the RID Master, it requests the RID Master to issue more RIDs for creating additional objects in the domain. When a domain controller exhausts its pool of RIDs, and the RID Master is unavailable, any new object in the domain cannot be created

The domain controller is only of one type but it can have different roles

Domain Naming master

RID master

PDC

Schema Master

Infrastructure master

Schema master (forest wide):

The Schema Master controls all updates to the Schema within the forest.

Domain Naming Master (forest wide):

The Domain Naming Master role is responsible for the creation and deletion of domains in the forest.

PDC Emulator (domain wide):

The PDC emulator role provides backwards compatability for Windows NT backup domain controllers (BDCs), the PDC emulator advertises itself as the primary domain controller for the domain. It also acts as the domain master browser and maintains the latest password for all users within the domain.

Infrastructure Master (domain wide):

The Infrastructure Manager role is responsible for updating references from objects within its domain with objects in other domains.

RID Master (domain wide):

The RID Master manages the Security Identifier (SID) for every object within the

A domain can have 1 RID master....

1 Domain Naming Master, 1 Schema Master, 1 PDC Emulator, 1 Infrastructure Master, 1 RID Master