MSDN Library

1.1 Glossary

The following terms are defined in [MS-GLOS]:

Active Directory



Globally Unique Identifier (GUID)

Interface Definition Language (IDL)

MD5 Hash

New Technology File System (NTFS)


Read-Only Domain Controller

Remote Procedure Call (RPC)

Security Principal Name (SPN)

Security Provider

Universally Unique Identifier (UUID)

Volume Sequence Number (VSN) (for FRS)

The following terms are specific to this document:

Active Directory Object: A distinct set of named attributes that represents a network resource. FRS uses Active Directory objects to represent servers that participate in replica sets and the topology that FRS uses to replicate data.

Active Directory Replication: The process by which the changes that are made to Active Directory objects on one domain controller are automatically synchronized with other domain controllers.

Change Order: A message that contains information about a file or folder that has changed on a replica. The change order is sent to the member's downstream partners. If the downstream partners accept the change, the partners request the associated staging file. After installing the changed file in their individual replica trees, the partners propagate the change order to their downstream partners.

Connection Join (Join): The process by which a connection session is established.

Connection Session: After FRS discovers a connection from Active Directory, FRS establishes a connection session with the remote connection partner based on the information provided by the connection object. The connection is called "joined" when a connection session is successfully established. This connection session is disconnected once the connection schedule is off (forbidding file replication on the connection).

Dampening: On receiving a remote change order, FRS must determine if the change order is already known to the local machine by using the version vector of the local machine. If the remote change order is known, FRS drops the change order and informs the upstream partner. This process is called "dampening" a change order.

DFS-R: A service that keeps DFS and SYSVOL folders in sync automatically. DFS-R is a state-based, multimaster replication system that supports replication scheduling and bandwidth throttling. This is a rewrite and new version of FRS. For more information, see [MS-FRS2].

Distributed File System (DFS): For more information, see [MS-DFSC] and [MS-DFSNM].

Directed Change Order: A change order directed to a single downstream partner and produced when the partner is a Version Vector Join (VVJoin), such as during initial sync.

Domain: A unit of security administration and delegation in a Windows network. For more information, see [MS-SECO] section 2.2.

Domain Controller (DC): A Windows-based server within a domain that functions as an authority for purposes of domain membership. It is responsible for administration of domain security. A DC makes its account database available to other machines in a controlled fashion. There may be multiple DCs in a single domain.

Domain Functional Level: Domain functionality activates features that affect the whole domain and that domain only. The domain-functional levels defined are Windows 2000 mixed (Default), Windows 2000 native, Windows 2003 interim, Windows Server 2003, and Windows Server 2008; for information on corresponding features and supported domain controllers, see [MS-_ADTS] section

Downstream Partner: The partner that receives change orders, files, and folders.

Dynamic Endpoint: A network-specific server address that is requested and assigned at run time. See also Endpoint. For more information, see [C706].

Event Time: See File Event Time.

File Attribute: 32-bit bitmask containing information on file properties. For instance, 0x00000001 is used for the read-only attribute.

File Event Time: The time at which a change to a file or folder is made. This may not be the same as the file create or last-write time. Restoring a file from a backup tape preserves the file create and last-write times, but the file event time is the time when the actual file restoration was performed.

File GUID: An identifying property of a file or folder in a replica tree. FRS creates and manages file GUIDs, which, along with the file version number and file event time, are stored in the IDTable. Each file and folder stores its file GUID as part of its attributes; therefore, corresponding files and folders across all replica set members have the same file GUID.

File Replication Service (FRS): One of the services offered by a DC, which is advertised through the DC Locator protocol. The service being offered to clients is a replicated data storage volume associated with the default naming context (NC).

File Version Number: A property of a file and folder in a replica tree that is incremented each time the file or folder is updated. The file version number is used to resolve concurrent updates originating from more than one member of the replica set. The version number is only incremented by the member that originated the file update. Other members that propagate the update do not change the version number.

Filter: A setting that excludes subfolders (and their contents) or files from replication. There are two types of filters: file filters and folder filters.

IDTable: A table of FRS state information that contains an entry with version and identity information for each file and folder in the replica tree. It is used to keep track of all files in the replica set and their histories.

Inbound Connection: For a given replica member, a component of the NT File Replication Service (NTFRS) member object in Active Directory that identifies upstream partners. An inbound connection exists for each upstream partner.

Inbound Log (InLog): A queue that stores pending change orders to be processed. As entries in the queue are processed, acknowledgments are sent to the upstream partners.

Initial Sync: The process a new member to the replica set before it is allowed to synchronize with its downstream partners. It is also called VVJoin.

Install (File or Folder): A process by which FRS applies a change order to the local file system to restore the file or folder as it is in the upstream partner. If the change order is for a deletion, the file or folder in the local file system is deleted (staging file is not needed). If the change order is for a renaming, the file or folder in the local file system is renamed (staging file is needed). If the change order is for a copying or creation, the file or folder is copied or created (staging file is needed). Installing a file or folder may fail if the file or folder is already opened by another process. If the installation failed, FRS retries installing the file or folder at a later time.

Local Change Order: A change order that is created because of a change to a file or folder on the local server. The local server becomes the originator of the change order and constructs a staging file.

Normal Sync: The synchronization among replicas after initial sync is done.

NTFRS Member: An object of class type nTFRSMember. Each NTFRS member object (class nTFRSMember) corresponds to a computer that is part of a replica set (see section NTFRS Member Object as specified in section

ObjectGuid: The GUID of an Active Directory object. For more information, see [MS-ADTS] section

Originator GUID: A GUID that is associated with each replica member. All change orders produced by a given replica member carry the replica member's originator GUID, which is saved in the IDTable. The originator GUID is not the same as the member GUID, which is the objectGuid of the NTFRS member object in Active Directory. For more information, see [MS-ADTS] section

Outbound Connection: For a given replica member, a component of the NTFRS member object in Active Directory that identifies downstream partners. An outbound connection exists for each downstream partner.

Outbound Log (OutLog): A table in the FRS database that stores pending change orders to be sent to downstream partners. The changes can originate locally or come from an upstream partner. These change orders are eventually sent to all outbound replica partners.

Parent GUID: The GUID of the parent folder that contains a particular file or folder in the replica tree.

Partner: A computer connected to a local computer though either inbound connections or outbound connections.

Primary Domain Controller (PDC): A single domain controller that is designated for various directory operations that must be centralized. A primary domain controller is not used in Windows Active Directory domains. Instead, one domain controller is assigned the primary domain controller emulator role for backward compatibility.

Remote Change Order: A change order received from an inbound (or upstream) partner that originated elsewhere in the replica set.

Replica Member (FRS Replica): A member of a replica set. Replica contains machine-specific information.

Replica Set: In the FRS, the replication of files and directories according to a predefined topology and schedule on a specific folder. The topology and schedule are collectively called a replica set. A replica set contains a set of replicas, one for each machine that participates in replication.

Replica Tree: The local replica tree root folder together with all files and directories underneath it, which usually is saved as a tree structure in the file system.

Replica Tree Root: The folder whose "children" (that is, files and folders) are replicated.

Retry Change Order: A change order that is in some state of completion but has been blocked for some reason and must be retried later.

Schedule: The frequency at which FRS replicates data under replica tree root.

Staging File: The backup of the changed file or folder. It encapsulates the data and attributes associated with a replicated file or folder. By creating the staging file, FRS ensures that file data can be supplied to partners regardless of any activity that might prevent access to the original file. The staging files MAY be compressed to save disk space and network bandwidth during replication.

System Volume (SYSVOL): A shared directory that stores the server copy of the domain public files that must be shared for common access and replication throughout a domain.

Upstream Partner: The partner that sends out change orders, files, and folders.

Version Vector: A vector of volume sequence numbers (VSNs), with one entry per replica set member, as identified by the originator GUID. All change orders carry the originator GUID of the originating member and the associated VSN. As each replica member receives the update, it tracks the VSN in a vector slot that is assigned to the originating member. This vector specifies if the replica tree is current with each member. The version vector is then used to filter updates from upstream partners that may have already been applied. The version vector is also delivered to the upstream partner when the two members establish a connection session. When a new connection is created, the version vector is used to scan the File ID table for more recent updates that are not seen by the new downstream partner (see section

Version Vector Join (VVJoin): The process in which a downstream partner joins with an upstream partner for the first time. Also called initial sync. This process is defined in section

Volatile Connection: An inbound connection created for the initial sync for a system volume (SYSVOL) replica set. After the initial sync is done, the volatile connection is destroyed. Volatile connections are not represented in Active Directory.

MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as described in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.

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