IBM MQ queues

A queue is a container for messages. Business applications that are connected to the queue manager that hosts the queue can retrieve messages from the queue or can put messages on the queue.

A queue has a limited capacity in terms of both the maximum number of messages that it can hold and the maximum length of those messages.

Queue type	Description
Local queue	A local queue is a definition of both a queue and the set of messages that are associated with the queue. The queue manager that hosts the queue receives messages in its local queues.
Transmission queue	Transmission queues are a special type of local queue. When the queue manager sends a message to a queue on a remote queue manager, the transmission queue stores the message locally until the queue on the remote queue manager is available. To create a transmission queue, create a local queue and change its Usage attribute to `Transmission`.
Remote queue definition	Remote queue definitions are definitions on the local queue manager of queues that belong to another queue manager. To send a message to a queue on a remote queue manager, the sender queue manager must have a remote definition of the target queue.
Alias queue	Alias queues are not actually queues; they are additional definitions of existing queues. You create alias queue definitions that refer to actual local queues but you can name the alias queue definition differently from the local queue (the base queue). This means that you can change the queues that an application uses without needing to change the application; you just create an alias queue definition that points to the new local queue.
Model queue	A model queue is a template for queues that you want the queue manager to create dynamically as required. When an application tries to put a message on a model queue, the queue manager dynamically creates a local queue with the same name as the model queue. Queues that are created in this way can either be temporary or permanent.
Cluster queue	A cluster queue is a queue that has been shared in a cluster so that all of the queue managers in the cluster can put and get from the queue using cluster channels. For more information, see Queue manager clusters.
Shared queue	z/OS® only. A shared queue is a queue that has the queue-sharing group disposition of `Shared`. All of the queue managers in the queue-sharing group can put and get from the queue without needing active channels. Only local queues can have the disposition of `Shared`. For more information, see Queue-sharing groups.
Group definition queue	z/OS only. A group queue is a queue that has the queue-sharing group disposition of `Group`. Each of the queue managers in the queue-sharing group has a copy of the queue (with the disposition `Copy`) stored on their own page set. Local, remote, alias, and model queues can have the disposition `Group`. For more information, see Queue-sharing groups.

For more information about queues, see Queues in the IBM® MQ online product documentation.