MQ host and distributed products

MQ host and distributed messaging products are used to support many different network configurations, all of which involve clients and servers, some examples of which are illustrated below.
Note: The terms client and server have very specific meanings within MQ host, distributed, and workstation messaging products, that do not always correspond to their meaning within MQe.
Figure 1. Simple host and distributed configurations
Three simple host and distributed configurations. a) A stand-alone server, b) two clients connected to a server, c) two interconnected servers each with two attached clients.
a) Standalone server
A queue manager runs on a single server. One or more applications run on that server, exchanging messages using queues.
b) Client/server
A queue manager runs on a server, but the clients each have access to it through a bidirectional connection called a client channel. The client channel implements something similar to a remote procedure call (RPC). Applications can run on the clients, accessing server queues. One advantage of the client/server configuration is that the client-messaging infrastructure is lightweight, because it depends on the server queue manager. One disadvantage is that clients and their associated server operate synchronously and, therefore, require the client channel to be available at all times.
c) Distributed client/server
This configuration involves multiple servers. In this example, servers exchange messages through unidirectional connections called message channels. Message channels assure safe and asynchronous exchange of message data. Message channels do not need to be available for the clients to continue processing. However, no messages can flow between servers when there are no communication links established between servers.

Parent topic: MQe in the MQ family