HP Integrity NonStop H-Series - Manual (Page 13)

Let us consider two brokers, Broker1 and Broker2, set up to form a cluster. These brokers are
connected locally by a network connector. The clients (producers and consumers) connect to the
cluster via the CIP subsystem.
Figure 4 Message flow in a cluster
1. Send
3. Acknowledge
5. Send
7. Acknowledge 11. Acknowledge
10. Send
2. Store
4. Fetch
8. Update
6. Store
9. Fetch
12. Update
Producer Broker 1 Broker 2 Consumer
SQL/MX
Database
The message flow through the cluster can be explained as follows:
•
A producer connects to a queue or topic in a cluster.
•
The CIP subsystem forwards the connection to Broker1.
•
A consumer connects to the cluster.
•
The CIP subsystem forwards the connection to Broker2. The consumer is subscribed to the
same queue or topic to which the producer is connected.
•
The producer sends a message (sequence 1 in Figure 4 (page 13) ).
•
Broker1 stores the message in the database and sends an acknowledgement to the producer
(2 and 3).
•
Since Broker2 has a duplex connection with Broker1, Broker2 subscribes to the message.
•
Broker1 fetches the message and sends it to Broker2 (4 and 5).
•
Broker2 stores the message in the database and sends the acknowledgement to Broker1 (6
and 7).
•
Broker1 marks the message as consumed and updates the database (8).
•
Broker 2 fetches the message and dispatches it to the consumer through the CIP subsystem (9
and 10).
•
Upon receiving the message, the consumer acknowledges the receipt of the message. Broker2
updates the database by marking the message as consumed and deletes it (11 and 12).
Message flow in a cluster 13