IBM MQ is a family of message-oriented middleware products that IBM launched in December 1993. It was originally called MQSeries, and was renamed WebSphere MQ in 2002 to join the suite of WebSphere products. In April 2014, it was renamed IBM MQ. The products that are included in the MQ family are IBM MQ, IBM MQ Advanced, IBM MQ Appliance, IBM MQ for z/OS, and IBM MQ on IBM Cloud. IBM MQ also has containerised deployment options.
MQ allows independent and potentially non-concurrent applications on a distributed system to securely communicate with each other, using messages. MQ is available on a large number of platforms (both IBM and non-IBM), including z/OS (mainframe), IBM i, Transaction Processing Facility, UNIX (AIX, HP-UX, Solaris), HP NonStop, OpenVMS, Linux, and Microsoft Windows.
MQ components
The core components of MQ are: Message: Messages are collections of binary or character (for instance ASCII or EBCDIC) data that have some meaning to a participating program. As in other communication protocols, storage, routing, and delivery information is added to the message before transmission and stripped from the message prior to delivery to the receiving application. Queue: Message queues are objects that store messages in an application. Queue Manager: a system service that provides a logical container for the message queue. It is responsible for transferring data to other queue managers via message channels. Although not strictly required for message-oriented middleware, is an IBM MQ prerequisite. Queue managers handle storage, timing issues, triggering, and all other functions not directly related to the actual movement of data.
Programs integrated with IBM MQ use a consistent application program interface (API) across all platforms.
Messaging types MQ supports point-to-point and publish–subscribe messaging.
APIs APIs directly supported by IBM include: IBM Message Queue Interface (MQI) for C, COBOL, PL/I, Java, Rexx, RPG, and C++ Java Message Service (JMS) XMS for C/C++ and .NET .NET REST SOAP
IBM lists alternative protocols as "APIs" as well. These include: MQTT (integral part of the MQ Telemetry component) AMQP 1.0 (optional addition)
Additional APIs (not officially supported) are also available via third parties, including: Perl interface (developed and contributed by Hildo Biersma), available from CPAN. Python interface PyMQI (originally developed by Les Smithson), available from PyPI PowerShell
Features One-time delivery: MQ uses once and once only delivery. This quality of service typically prevents message loss or duplication.
Asynchronous messaging: MQ provides application designers with a mechanism to achieve non-time-dependent architecture. Messages can be sent from one application to another, regardless of whether the applications are running at the same time. If a message receiver application is not running when a sender sends it a message, the queue manager will hold the message until the receiver asks for it. Ordering of all messages is preserved, by default this is in FIFO order of receipt at the local queue within priority of the message.
Data transformation: e.g. Big Endian to Little Endian, or EBCDIC to ASCII. This is accomplished through the use of message data exits. Exits are compiled applications that run on the queue manager host, and are executed by the IBM MQ software at the time data transformation is needed.
Message-driven architecture framework: IBM MQ allows receipt of messages to "trigger" other applications to run.
Range of APIs: It implements the Java Message Service (JMS) standard API, and also has its own proprietary API, known as the Message Queuing Interface (MQI), which preceded the JMS several years in existence. As of version 8.0.0.4, MQ also supports the MQ Light API.
Clustering: Multiple MQ implementations share the processing of messages, providing load balancing.
Communication Queue managers communicate with the outside world either through: Bindings: a direct software connection. Generally faster, but limited to programs running on the same physical host as the queue manager. A network or "client" connection: applications using a client connection can connect to a queue manager on any other host in the network. The physical location of the queue manager is irrelevant, as long as it is reachable over the network. SNA APPC, TCP/IP, NetBIOS, and SPX may be used. There is also a MQ Internet Pass-Thru (MQIPT) for use over the TCP/IP Internet.
Communication between queue managers This relies on a channel. Each queue manager uses one or more channels to send and receive data to other queue managers. A channel is uni-directional; a second channel is required to return data. In a TCP/IP based network, a channel sends or receives data on a specific port.
Channel types: Sending channel: has a defined destination and is associated with a specific transmission queue (the mechanism by which messages are queued awaiting transmission on the channel). Receiving channel: receives data from any other queue manager with a sending channel of the same name.
When a receiving channel receives a message, it is examined to see which queue manager and queue it is destined for. In the event of a communications failure, MQ can automatically re-establish a connection when the problem is resolved.
The listener is the application's network interface to the queue manager. The listener detects connections from incoming channels, and manages the connection of the sending channels to the receiving channels. In a TCP/IP network, the listener will "listen" for connections on a specific port.
Transmitting data to a queue on another queue manager Queue types: Local queue: represents the location where data is stored awaiting processing. Remote queue: represents a queue on another queue manager. They define the destination queue, which is one element of the routing mechanism for messages. Cluster queue: represents a queue which is reachable via any queue manager in its cluster.
A message is placed on a remote queue. The messages goes to a temporary storage transmission queue associated with a channel. On placing a message on a remote queue, the message is transmitted across the remote channel. If the transmission is successful, the message is removed from the transmit queue. On receiving a message, the receiving queue manager examines the message to determine whether the message is for itself or if must go to another queue manager. If the receiving queue manager, the required queue will be checked, and if it exists, the message is placed on this queue. If not, the message is placed on the dead letter queue. MQ has features to manage efficient transmission of data across a variety of communication media. For example, messages can be batched together until a queue reaches a particular depth.
Ordering Although the queue is FIFO, it is ordered based on the receipt in the local queue, not the committing of the message from the sender. Messages can be prioritized, and by default, the queue is prioritized in order of arrival. Queues will only be in sequence of addition if the message is added locally. Message grouping can be used to ensure a set of messages are in a specific order, aside from that, if sequence is critical, it is the application's responsibility to place sequence data in the message or implement a handshaking mechanism via a return queue. In reality, ordering will be maintained in straightforward configurations.
The log The other element of a queue manager is the log. As a message is placed on a queue or a configuration change is made, the data is also logged. In the event of a failure, the log is used to recreate damaged objects and recreate messages. Only persistent messages are recreated when a failure occurs—"non-persistent" messages are lost. Non-persistent messages can be sent across a channel set to a fast mode, in which delivery is not assured in the event of a channel failure.
MQ supports both circular and linear logging.
Retrieving messages from queues Information can be retrieved from queues either by polling the queue to check for available data at suitable intervals, or alternatively MQ can trigger an event, allowing a client application to respond to the delivery of a message.
Availability IBM MQ offers a variety of solutions to cater for availability:
Native HA (MQ Advanced on container platform like Red Hat OpenShift / CNFC Kubernetes and Red Hat Linux): It is a quorum-based architecture that requires one active node and two replica nodes. The logs are synchronously replicated between the nodes. It also provides Cross Region Replication feature that allows the Native HA cluster (in Live mode) to replicate asynchronously to another Native HA cluster (in Recovery mode).
Replicated Data Queue Manager (RDQM / 'Easy HA'- MQ Advanced on Red Hat Linux only): Synchronous replication between three servers that all share a floating IP address.
Queue Manager Clusters: Groups of two or more queue managers on one or more computers are defined to a cluster, providing automatic interconnection, and allow queues to be shared among them for load balancing and redundancy.
Queue Sharing Groups (z/OS only): In a Shared Queue environment, an application can connect to any of the queue managers within the queue-sharing group. Because all the queue managers in the queue-sharing group can access the same set of shared queues, the application does not depend on the availability of a particular queue manager. This gives greater availability if a queue manager stops because all the other queue managers in the queue-sharing group can continue processing the queue.
Multi-Instance Queue Managers (available from v7.0.1): Instances of the same queue manager are configured on two or more computers with their queues and meta data residing on shared storage. By starting multiple instances, one instance becomes the active instance and the other instances become standbys. If the active instance fails, a standby instance running on a different computer automatically takes over.
History
Version release dates
Version name Release date IBM MQ 10.0 LTS16 June 2026IBM MQ 9.4 LTS18 June 2024IBM MQ 9.3 LTS23 June 2022 IBM MQ 9.2 LTS 23 July 2020 IBM MQ 9.1 LTS 23 July 2018 IBM MQ on IBM Cloud 13 March 2018 IBM MQ for HPE Nonstop 8.023 June 2017 IBM MQ 9.0 LTS 2 June 2016 IBM MQ 8.0 23 May 2014 WebSphere MQ 7.5 15 June 2012 WebSphere MQ 7.1 November 2011 WebSphere MQ 7.0 z/OS June 2008 WebSphere MQ 7.0 (Distributed, iSeries) May 2008 WebSphere MQ 6.0 z/OS June 2005 WebSphere MQ 6.0 (Distributed, iSeries) May 2005 WebSphere MQ 5.3 z/OS June 2002 WebSphere MQ 5.3 (Distributed, iSeries) June, July, Oct, Nov 2002 MQSeries 5.2 (Distributed) Dec 2000 MQSeries for OS/390 V5.2 Nov 2000 MQSeries for AS/400 V5.1 July-Aug 2000 MQSeries for OS/390 V2.1 Feb 1999 MQSeries 5.1 April (NT), June 1999 MQSeries for AS/400 V4.2 Feb 1998 MQSeries 5.0 October 1997 MQSeries for MVS/ESA 1.2 29 August 1997 MQSeries for MVS 1.1.4, June 1996 MQSeries 2.2 (Sun OS/Solaris, DC/OSx) June, July 1996 MQSeries 2.0 Windows NT 2Q 1996 MQSeries 2.2 (HP, SCO) 4Q 1995 MQSeries for MVS 1.1.3 May 1995 MQSeries 2.0 (OS/2, AIX) Feb 1995 (the beginning of the end of ezBridge) MQM/400 V3 4Q 1994 ezBridge Transact for MQSeries 3.0 July 1994 MQSeries for MVS 1.1.2 June 1994 MQM/400 V2.3 Feb/April 1994 ezBridge Transact for MQSeries March, Sept, Nov, Dec 1993 (different platforms) MQSeries for MVS V1.1.1 December 31, 1993
Version end of support dates The following table applies to MQ software. The MQ Appliance has different lifecycle dates for both firmware and hardware than those in the table.