Also, a header is used on the message to prevent loop detection.
Carl.
Jonathan Robie wrote:
Bidirectional links are fine, and automatically detect loops. Tree,
star, or line topologies are fine too, and bidirectional links between
any pair of brokers are fine. A ring topology is also possible, if
only unidirectional links are used.
Here's the rule:
For any pair of nodes A,B in a federated network, there should be only
one path from A to B. If there is more than one path, message loops
can cause duplicate message transmission and flood the federated
network. The topologies discussed above do not have message loops. A
ring topology with bidirectional links is one example of a topology
that does cause this problem, because a given broker can receive the
same message from two different brokers. Mesh topologies can also
cause this problem.
Every message transfer takes time. For better performance, you should
minimize the number of brokers between the message origin and final
destination. In most cases, tree or star topologies do this best.
Hope this helps!
Jonathan
H. Charles Tang wrote:
Have created 2 static routes as follows between our 2 qpid daemons
housed on two linux hosts respectively:
qpid-route route add host1:5000 host2:5000 amq.topic topic.foo
qpid-route route add host2:5000 host1:5000 amq.topic topic.foo
Does this create an infinite loop for a message between 2 qpids? Our
experiment confirmed the looping scenario.
Then how does one create a bi-directional route? or how do we
interpret the following in the qpid documentation:
"Routes are unidirectional. A single route provides for the flow of
messages in one direction across a link. If bidirectional
connectivity is required (and it almost always is), then a pair of
routes must be created, one for each direction of message flow."
Finally does qpid (daemon) do loop detection/handling?
Thanks.
Charles
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