  In distributed systems, where multi-party communication is essential, two
communication paradigms are ever present: (1) one-to-many, commonly denoted as
broadcast; and (2) many-to-one denoted as aggregation or collection.
  In this paper we present the BBC process calculus, which inherently models
the broadcast and aggregation communication modes. We then apply this process
calculus to reason on hierarchical network structure and provide examples on
its expressive power.
