| Address | An address class |
| LossyReceivingPort | A receiving port simulating link loss and delay |
| Packet | A Packet class |
| PacketHdr | A Packet Header class |
| Port | Port class abstacts functions of communication interfaces |
| ReceivingPort | A Receiving Port Class |
| SendingPort | SendingPort is an subclass of Port for sending purpose |
| TxTimer | A timer to schedule a later event/transmission occured in a port |
1.4.2