Network Deployment (Distributed operating systems), v8.0 > Applications > Service integration > Bus destinations > Message points > Remote message points
Point-to-point messaging example by using remote queue points
When a producing or consuming application is remote from its destination, remote queue points are used to manage the flow of messages between the messaging engine where the destination is located, and the messaging engine to which the application is attached.
The following figure illustrates the use of remote queue points in point-to-point messaging. The producing application attaches to messaging engine ME1, but the bus destination targeted by the application has a queue point on ME2. The queue point on ME2 is represented at runtime by a remote queue point on ME1. The remote queue point receives messages from the application and then reliably transmits them to the queue point on ME2. Likewise, the consuming application attaches to ME3 and consumes messages from the queue point on ME2 through a remote queue point on ME3.
Figure 1. Point-to-point message production and consumption by using remote queue points.
The sequence of steps involved in remote message production is as follows:
- The producing application, attached to ME1, sends a message to the queue destination, which has a queue point defined on ME2.
- Messages are queued up on the remote queue point on ME1 before transmission to the queue point on ME2.
- The message is sent to the queue point on ME2 as soon as possible. ME1 remembers the existence of the message until ME2 confirms that it has received the message.
The sequence of steps involved in remote message consumption is as follows:
- The consuming application, attached to ME3, attempts to consume a message from the queue destination.
- ME3 sends a message request to the queue point on ME2.
- When a message that satisfies the criteria of the message request is available at the queue point on ME2, the message is sent to the remote queue point on ME3.
- The message is delivered from the remote queue point to the consuming application. If the application consumes the message, the message is deleted from the queue point on ME2. If the application does not consume the message, the message is made available again on the queue point on ME2 for other applications to consume. In either case, the message request is completed and removed from the remote queue point on ME3.
Publish/subscribe messaging example by using remote publication points
Inbound messages [Collection]
Message requests [Collection]
Known remote queue points [Collection]
Known remote queue points [Settings]
Remote queue points [Collection]
Remote queue points [Settings]
Concept topic