CORBA Event Service is a centralise implementation of #202207041109 which utilises the event channel (a common software bus shared by other objects) to allow pushing and/or pulling of event notifications.
In push mode, the publisher inform the event occurrence to it, and the channel will distribute it to all the registered subscribers.
In pull mode, the subscriber will poll the channel periodically where the publisher will respond to it by sending the event data if such event happened.