1.1 Glossary

This document uses the following terms:

connector queue: A queue used by a connector server. Messages sent to foreign queues are temporarily stored in a connector queue before they are retrieved by the connector application.

Coordinated Universal Time (UTC): A high-precision atomic time standard that approximately tracks Universal Time (UT). It is the basis for legal, civil time all over the Earth. Time zones around the world are expressed as positive and negative offsets from UTC. In this role, it is also referred to as Zulu time (Z) and Greenwich Mean Time (GMT). In these specifications, all references to UTC refer to the time at UTC-0 (or GMT).

dead-letter queue: A queue that contains messages that were sent from a host with a request for negative source journaling and that could not be delivered. Message Queuing provides a transactional dead-letter queue and a non-transactional dead-letter queue.

durable message: A message that is written to a stable store during processing to ensure persistence during a computer failure or restart.

globally unique identifier (GUID): A term used interchangeably with universally unique identifier (UUID) in Microsoft protocol technical documents (TDs). Interchanging the usage of these terms does not imply or require a specific algorithm or mechanism to generate the value. 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 GUID. See also universally unique identifier (UUID).

message: A data structure representing a unit of data transfer between distributed applications. A message has message properties, which may include message header properties, a message body property, and message trailer properties.

message body: A distinguished message property that represents the application payload.

message packet header: The set of message properties in a message packet that precedes the message body property. Also called a message header.

message queue: A data structure containing an ordered list of zero or more messages. A queue has a head and a tail and supports a first in, first out (FIFO) access pattern. Messages are appended to the tail through a write operation (Send) that appends the message and increments the tail pointer. Messages are consumed from the head through a destructive read operation (Receive) that deletes the message and increments the head pointer. A message at the head can also be read through a nondestructive read operation (Peek).

message queuing: A communications service that provides asynchronous and reliable message passing between distributed client applications. In message queuing, clients send messages to message queues and consume messages from message queues. The message queues provide persistence of the messages, which enables the sending and receiving client applications to operate asynchronously from each other.

Microsoft Message Queuing (MSMQ): A communications service that provides asynchronous and reliable message passing between distributed applications. In Message Queuing, applications send messages to queues and consume messages from queues. The queues provide persistence of the messages, enabling the sending and receiving applications to operate asynchronously from one another.

network address translation (NAT): The process of converting between IP addresses used within an intranet, or other private network, and Internet IP addresses.

outgoing queue: A temporary internal queue that holds messages for a remote destination queue. The path name of an outgoing queue is identical to the path name of the corresponding destination queue. An outgoing queue is distinguished from its corresponding destination queue by the fact that the outgoing queue is located on the sending computer. The format name of an outgoing queue is identical to the format name used by the messages to reference the destination queue. Messages that reference the destination queue using a different format name are placed in a different outgoing queue.

queue: An object that holds messages passed between applications or messages passed between Message Queuing and applications. In general, applications can send messages to queues and read messages from queues.

queue journal: A queue that contains copies of the messages sent from a host when positive source journaling is requested.

queue manager (QM): A message queuing service that manages queues deployed on a computer. A queue manager can also provide asynchronous transfer of messages to queues deployed on other queue managers.

regular message: A message that is stored only in computer memory while it is processed and cannot be recovered after a computer failure or restart.

sequence: The set of message packets sent over a session that represent a message sequence. A message is associated with a sequence number that corresponds to its position within the sequence. Sequence numbers begin with 1 and increment by 1 with each subsequent message.

source journaling: The process of storing copies of outgoing messages on the source computer. Source journaling is configured on a per-message basis and can be used to track messages that were sent successfully, messages that could not be delivered, or both.

stream: A sequence of messages whose delivery is guaranteed exactly once and in order.

stream message: A durable message that is delivered to the receiver exactly once and in sequence with other messages sent on the stream.

stream receipt: An acknowledgment message that indicates the in-order receipt of messages that make up a stream.

system queue: An internal queue that is used by the queue manager for a purpose other than holding messages destined for a remote destination queue.

transactional message: A message sent as part of a transaction. Transaction messages must be sent to transactional queues.

transactional queue: A queue that contains only transactional messages.

transparent store-and-forward server: A queue manager that is configured to accept and forward messages that have another queue manager as the final destination.

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.

XML: The Extensible Markup Language, as described in [XML1.0].

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.