A uniqe sequence number counter is allocated to a distinct circuitcode and then can be safely shared among multiple Simulator instances with the same circuitcode. Consider a scenario which possibly leads to sequence number conflicts: 1. establish a connection to a simlator (create a Simulator instance and start sequence numbers from 1), 2. disconnect that connection (free that instance), 3. establish a connection to the same simulator again (create another Simulator instance and start sequence numbers from 1 again!!)