• c : station
• C : station
• counter_variable : station
• current_customer : station
• current_queue : station
• DepartureTimes : station
• max_queue_len : graph
• mxN : station
• N : graph
• n : station
• N : tandem
• Na : station
• network : graph
• num_nodes : graph
• number_of_station : tandem
• server_status : station
• station_list : graph , tandem
• system_counter_variable : graph , tandem
• td : station