Promela and Model Description
. Promela provides a high level abstraction of protocol or distributed system
  in general. With the C-like syntax, it describes the behavior and interaction
  among processes yet suppressing unrelated details.
. Concepts in Promela
   1)  Process
        Processes are global objects that run concurrently. It’s used to describe
        behavior.
   2)  Channels and Variables
        Channels and variables describe the environment in which processes run.