The packet size is 24 bytes payload, and the overheads are as follows
Application layer -- Payload = 24 Bytes
Transport layer -- 8 bytes Overhead = 32 Bytes (Total)
Network layer -- 28 bytes Overhead which consists of 20 of DSR + 8 IP = 60 Bytes (Total)
MAC Layer -- 5 Byes Overhead = 65 Bytes (Total)
PHY Layer -- 6 Bytes
Overhead = 71 Bytes (Total)
Users can consider the packet size as either 24 or of 71 depending on whether they need Application throughput or Phy Throughput.
Users should convert packet size to bits by multiplying by 8, and the simulation time given by NetSim is in Microseconds, so it should be converted it to seconds by dividing by 1,000,000.