MSMQ Dependent Clients

MSMQ dependent clients function much like MSMQ independent clients; however they cannot function without synchronous access to a PEC, PSC, BSC, or MSMQ routing server (referred to as the dependent client's supporting server). MSMQ dependent clients rely on their assigned server to perform all standard MSMQ functions on their behalf (such as creating queues, sending messages, and receiving messages).

MSMQ dependent clients can be installed on computers running Windows 95, and Intel-compatible computers running Windows NT Workstation or Windows NT Server. (MSMQ dependent clients cannot be installed on Alpha computers running Windows NT). MSMQ servers can support up to 15 dependent clients.

The following diagram shows the logical configuration in which MSMQ dependent clients function:

Figure 1.4

This configuration provides the following advantages:

MSMQ dependent clients on computers running Windows 95 can send and receive transactional messages.
Server disk space is used to store messages, reducing dependent client hardware requirements. Should more resources be required (memory or hard disk space) fewer computers must be upgraded.
With fewer points of administration you have fewer computers to back up and fewer journal and dead-letter queues to monitor.

This configuration also has the following limitations:

Because the MSMQ service runs on the supporting server, encrypted messages sent to or received by MSMQ dependent clients travel between the dependent client and supporting server in an unencrypted format.
Because MSMQ dependent clients run the MS DTC proxy, they cannot transact MSMQ functions with transactional resources on the dependent client computer; they can transact MSMQ functions only with transactional resources on the supporting server.
Because MSMQ dependent clients do not run the MSMQ service, they do not appear in MSMQ Explorer. However, when you view the properties of a server, the Dependent Clients tab displays which dependent clients the server supports. You can also use MSMQ Explorer to view the creation of queues and messaging activity for dependent clients on the dependent client's supporting server.

Note An MSMQ dependent client and its assigned server do not have to be in the same site. However, because all of the dependent client's communication goes through the server, if the communication to the server is slow or expensive, all dependent client communication will also be slow or expensive.

For information on the message time-to-reach-queue property, see the MSMQ SDK.

MSMQ clients (both independent and dependent) are limited to a maximum of ten concurrent sessions with other MSMQ clients.