I'm in the process to plan for a messaging framework and I thought of using an AMQP product (RabbitMQ, OpenMQ, Apache Qpid... etc.) but while searching I found it hard to decide. the conditions of the network are as follows:
- Topology: Fully-connected (or completely-connected)
- Number of Servers: 4
- Type of messaging: Topic Messaging - publish/subscribe
While reading about the AMQP products it was not so clear how they deal with infinite looping messages in a federation.
- Qpid: clearly states that an ad-hoc connection will cause the problem.
- RabbitMQ: wasn't so clear how to use federation.
- openAMQ: I feel that would solve my issue but still not sure and here comes my question!
openAMQ states a fully connected topology example here (as shown in the last figure in the link): http://www.openamq.org/tutorial:broker-federation
in another document of openAMQ the following statement appears:
http://www.openamq.org/doc:user-3-advanced#toc61
"Federated publish-subscribe creates extra hops when the publisher and subscriber are both on a child server. In this case, messages are sent first to the parent, root server and from there back out to all child servers that need them. This is how we avoid delivering the same message more than once. However it creates extra latency. We would normally put important publishers on the root parent server."
the first example causes message duplication but the second document talks about this as a limitation in a tree topology(as I did understand)!
now.. does openAMQ support a fully-connected network without causing looping messages or not? not could you recommend me a product that doesn't?