1.1 Glossary

This document uses the following terms:

access control list (ACL): A list of access control entries (ACEs) that collectively describe the security rules for authorizing access to some resource; for example, an object or set of objects.

Active Directory: A general-purpose network directory service. Active Directory also refers to the Windows implementation of a directory service. Active Directory stores information about a variety of objects in the network. Importantly, user accounts, computer accounts, groups, and all related credential information used by the Windows implementation of Kerberos are stored in Active Directory. Active Directory is either deployed as Active Directory Domain Services (AD DS) or Active Directory Lightweight Directory Services (AD LDS). [MS-ADTS] describes both forms. For more information, see [MS-AUTHSOD] section, Lightweight Directory Access Protocol (LDAP) versions 2 and 3, Kerberos, and DNS.

authentication level: A numeric value indicating the level of authentication or message protection that remote procedure call (RPC) will apply to a specific message exchange. For more information, see [C706] section and [MS-RPCE].

Authentication Service (AS): A service that issues ticket granting tickets (TGTs), which are used for authenticating principals within the realm or domain served by the Authentication Service.

client: In DFS-R, a replicating machine acts as a client when it receives replicated files from its upstream partner. Use of the terminology client stipulates that the machine contact its upstream server, and is responsible for initiating communication related to receiving replicated files. It does not imply anything about the operating system version or the function of the machine.

connection: In DFS-R, a pair of client and server replication partners.

content set: See replicated folder.

database: In Distributed File System Replication (DFS-R), the database maintained by the Microsoft implementation of DFS-R maintains the local version chain vector and one record for each resource that is tracked, including tombstones for deleted resources, such that deletion of files can be propagated in a timely fashion.

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 Replication (DFS-R): A service that keeps DFS folders in sync automatically. DFS-R is a state-based, multi-master replication system that supports replication scheduling and bandwidth throttling. This is a rewrite and new version of the File Replication Service (FRS). For more information, see [MS-FRS2].

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

Fence: An auxiliary time stamp included in an update.

File data: The data stream of the replicated content.

file system: A system that enables applications to store and retrieve files on storage devices. Files are placed in a hierarchical structure. The file system specifies naming conventions for files and the format for specifying the path to a file in the tree structure. Each file system consists of one or more drivers and DLLs that define the data formats and features of the file system. File systems can exist on the following storage devices: diskettes, hard disks, jukeboxes, removable optical disks, and tape backup units.

fully qualified domain name (FQDN): An unambiguous domain name that gives an absolute location in the Domain Name System's (DNS) hierarchy tree, as defined in [RFC1035] section 3.1 and [RFC2181] section 11.

Global Version Sequence Numbers (GVSN): A GVSN is a pair: Machine identifier and version sequence number (VSN). Although two machines might assign the same VSN, because they have different machine identifiers, the associated GVSNs differ. A GVSN is used to identify a unique version of a unique resource. In other words, no two different resources ever get assigned the same GVSN, and no two different updates to the same resource ever get assigned the same GVSN.

hash: The collision-resistant substrate of a sequence of bytes. Well-known hash algorithms for computing hashes include MD4, MD5, and SHA-1.

Interface Definition Language (IDL): The International Standards Organization (ISO) standard language for specifying the interface for remote procedure calls. For more information, see [C706] section 4.

little-endian: Multiple-byte values that are byte-ordered with the least significant byte stored in the memory location with the lowest address.

logical connection: The state maintained on client and server in association with a connectionId.

member (DFS-R): In the Distributed File System Replication Protocol, a computer participating in replication.

Microsoft Interface Definition Language (MIDL): The Microsoft implementation and extension of the OSF-DCE Interface Definition Language (IDL). MIDL can also mean the Interface Definition Language (IDL) compiler provided by Microsoft. For more information, see [MS-RPCE].

NT file system (NTFS): A proprietary Microsoft file system. For more information, see [MSFT-NTFS].

persist: The process of storing data in a memory medium that does not require electricity to maintain the data that it stores. Examples of such mediums are hard disks, CDs, non-volatile RAM, and memory sticks.

Persist: To commit (or save) data to Persistent Storage.

Persistent Storage: Nonvolatile storage mediums, such as magnetic disks, tapes, and optical disks.

principal name: The computer or user name that is maintained and authenticated by the Active Directory directory service.

RDC FilterMax algorithm: The algorithm that RDC uses to determine the cut points in a file. The RDC FilterMax algorithm has the property that it will often find cut points that result in identical chunks being found in differing files, even when the files differ by insertions and deletions of bytes, not simply by length-preserving byte modifications. See section

read-only replicated folders: A folder where local changes are not replicated out and reverted by replicating back previous content.

remote differential compression (RDC): Any of a class of compression algorithms that are designed to compare two files residing on different machines without requiring one of the files to be transmitted in its entirety to the other machine. For more information, see [MS-RDC].

remote procedure call (RPC): A context-dependent term commonly overloaded with three meanings. Note that much of the industry literature concerning RPC technologies uses this term interchangeably for any of the three meanings. Following are the three definitions: (*) The runtime environment providing remote procedure call facilities. The preferred usage for this meaning is "RPC runtime". (*) The pattern of request and response message exchange between two parties (typically, a client and a server). The preferred usage for this meaning is "RPC exchange". (*) A single message from an exchange as defined in the previous definition. The preferred usage for this term is "RPC message". For more information about RPC, see [C706].

replica set: In File Replication Service (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.

replicated folder: The root of a replicated tree. All files and subfolders (recursively) are replicated.

replication group: A container for a set of replicated folders sharing the same connections to replication partners.

replication session: The state that is maintained when replicating files in the context of a replicated folder and connection.

selective single master: A replication mode in which changes from only a single machine propagate to other machines.

server: A replicating machine that sends replicated files to a partner (client). The term "server" refers to the machine acting in response to requests from partners that want to receive replicated files.

SHA-1 hash: A hashing algorithm as specified in [FIPS180-2] that was developed by the National Institute of Standards and Technology (NIST) and the National Security Agency (NSA).

slow sync: The nominator for a synchronization subprotocol that is used to perform a consistency check between the databases of two partners.

tombstone: In Distributed File System Replication (DFS-R), an update pertaining to a file deletion.

topology: The structure of the connections between members.

unique identifier (UID): A pair consisting of a GUID and a version sequence number to identify each resource uniquely. The UID is used to track the object for its entire lifetime through any number of times that the object is modified or renamed.

universally unique identifier (UUID): A 128-bit value. UUIDs can be used for multiple purposes, from tagging objects with an extremely short lifetime, to reliably identifying very persistent objects in cross-process communication such as client and server interfaces, manager entry-point vectors, and RPC objects. UUIDs are highly likely to be unique. UUIDs are also known as globally unique identifiers (GUIDs) and these terms are used interchangeably in the Microsoft protocol technical documents (TDs). Interchanging the usage of these terms does not imply or require a specific algorithm or mechanism to generate the UUID. Specifically, the use of this term does not imply or require that the algorithms described in [RFC4122] or [C706] must be used for generating the UUID.

update: An add, modify, or delete of one or more objects or attribute values.  See originating update, replicated update.

version chain vector: A data structure that maps machine GUIDs to sets of version sequence numbers.

version sequence number (VSN): A 64-bit unsigned number. Version sequence numbers are assigned to global version sequence numbers as part of file metadata in monotonic increasing order.

volume: A group of one or more partitions that forms a logical region of storage and the basis for a file system. A volume is an area on a storage device that is managed by the file system as a discrete logical storage unit. A partition contains at least one volume, and a volume can exist on one or more partitions.

volume sequence number (VSN) (for file replication service): A unique sequence number assigned to a change order to order the event sequence in a replica. It is a monotonically increasing sequence number assigned to each change that originates on a given replica member. If one change order has a smaller volume sequence number (VSN) than another change order, the change that the first change order represents occurs before the change that the second change order represents.

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