In the early days of EAI, the applications needed to interact with each other in various formats, which may include communicating some information or exchanging data. To facilitate this exchange, the organizations came up with a hub and spoke model for EAI.
In this hub and spoke model, there's a router-based middleware component and a concept of events. Whenever there was some change in the state of one of the applications, the application used to generate an event. The other applications subscribed to the event stream they were interested in.
Now, whenever a new event was generated, the router was responsible for the delivery of the event to the interested applications handling the conversion of data from one format into another, so that the applications could communicate with each other. In this kind of approach, the router became the central...
