1 – files are created consecutively, i.e., the longer your simulation, the more files will be transmitted.
2 – reading time: a file of arbitrary size is generated and the transmit buffer is being emptied by transmitting over the channel. Once a file is completely transmitted, there is a reading time (chosen from a random distribution as specified in the document I referenced above). After this reading time a new file is generated. (there is no term ‘waiting time’ specified in the document, I used in instead of ‘reading time’ – sorry if that caused confusion)
3 – the simulator is transmitting bits, while the file size is generated in bytes. Therefore, it is multiplied by 8.