A Broker routes events incoming from Publishers to Subscribers that are subscribed to respective Topics
A Router is a Peer of the roles Broker and Dealer which is responsible for generic call and event routing and do not run any application code.
A Session is a transient conversation between two Peers (tipically a a Router and a Client) attached to a Realm and running over a Transport.
A Transport connects two Peers and provides a channel over which Messages for a Session can flow in both directions.
A Session is a transient conversation between two Peers (tipically a a Router and a Client) attached to a Realm and running over a Transport.
Routing occurs only between Sessions that have joined the same Realm