When an AMQP federation instance attempts to federate an address or queue
it can fail if the remote address or queue is not present or cannot be
created based on broker policy. A federation link can also closed if the
federated resource is removed from the remote broker by management etc.
In those cases the remote broker should note the resources that were
targets of federation and send alerts to the source federation broker to
notify it that these resources become available for federation and the
source should attempt again to create federation links if demand still
exists. This allows an AMQP federation instance to heal itself based on
updates from the remote.
94b6c0ec6e