Learning Windows Server 2003

The Microsoft Message Queue

The Microsoft Message Queuing Service (MSMQ) provides you, as the system administrator, with a way to collect messaging transactions from various messaging-aware applications and queue them until applications are ready to process them. Messages, in this case, aren’t like email messages between human users, but are functional messages or data exchanged between applications.

What is MSMQ used for? The MSMQ services come into play when one application wants to exchange a message with another application, but that particular application isn’t responding. When one person needs to communicate fairly quickly with another person, he typically uses a phone. If the person he is trying to reach isn’t at his desk, and there is no voice mail or answering machine, the original caller needs to continue trying to reach the person—which can turn into a big waste of time. However, if he can leave a voice mail message in the other person’s message “queue,” the caller can go on about his other work and wait for the other person to deal with the message and take any appropriate action. MSMQ works the same way, providing a storage-and-retrieval service for applications that are available to accept messages sent to them. This allows sending applications to get on with their other processes without dedicating resources to continuing attempts to transmit messages to unavailable applications.

The queue—the holding bin for these messages—comes in different types and performs different ...