## 4 Implementation Details
### Generating Heterogeneous Arrivals
Figure 2:7 Delay for Prioritization using Fragmentation (Fragment Size = 1B). Subsequently, Figure 13 provides comparison of PDR for low and high priority traffic for the cases of with and without fragmentation. When fragment size is set to 1B, the low priority traffic faces high PDR and high priority traffic faces lower PDR. In contrast, when the fragment size reaches to full packet size, the delay trends become opposite for both the priorities because now the lower priority traffic gets higher chances of complete transmission before getting dropped. An interesting finding observed in Figure 13a is that for low priority traffic, as the packet size is increased, the delay trend converges for different fragment sizes. This is because even if the fragment size is increased to the full packet size, the PDR will still be high as more packets will be dropped due to waiting more than 2 s; this result confirms the findings earlier depicted in Figure 2:8 On the other hand, in Figure 13b, when the packet size was increased, the difference between the PDR values for with and without fragmentation scheme increased as instead of waiting for the full packet of 300B to be transmitted, the high priority traffic would now wait only for transmission of 1B fragment. #### 6.3.2 Influence of Varying Fragment Size

The influence of varying fragment size \(\mathrm{S_{FRAG}}\) for the traffic of both priorities was studied in this experiment. The results of delay for low priority CBR traffic have been shown in Figure 2:9 Packet size was assumed to be 60, 120, 180, 240 and 300 bytes. For each packet, the fragment size was varied from 1B to the maximum packet size (when the fragment size = 1B, maximum number of fragments will be transmitted, and when fragment size = packet size, the complete packet is transmitted as a single unit). As shown in the Figure 14, for each value of the packet size, the delay reduces with the increasing fragment size; this happens because the number of interruptible periods between the fragments reduces, which offers a lower chance to high priority traffic to take up the medium during the ongoing transmission. Figure 3.0 Comparing the Influence of Fragmentation on PDR (**a**) Low Priority Traffic (**b**) High Priority Traffic. In each of the graphs shown in Figure 14, the sharp decline in the value of delay has been seen initially, whereas the trend becomes steady for the higher values of fragment sizes. Let us consider the variation of fragment sizes in Figure 14a for the explanation of trend, where the packet size was 60B. Initially, \(\mathrm{S_{FRAG}}\) was increased from 1B to 2B and then from 2B to 3B. Considering \(\mathrm{S_{FRAG}}=1\)B, there would be 60 fragments and hence 60 interruptible periods, whereas when \(\mathrm{S_{FRAG}}\) increases to 2B, the number of interruptible periods reduces to 30. This shows that there occurs a difference of 30 interruptible periods only by changing \(\mathrm{S_{FRAG}}\) by 1B. However, when the \(\mathrm{S_{FRAG}}\) increases from 2B (with 30 interruptible periods) to \(\mathrm{S_{FRAG}}=3\)B (with 20 interruptible periods); only 10 interruptible periods are reduced with the increment of 1B in \(\mathrm{S_{FRAG}}\). As \(\mathrm{S_{FRAG}}\) keeps on increasing, the difference in number of interruptible periods further reduces. Hence, initially we see a sharp decline in delay due to having higher differences in the number of interruptible periods, which gradually reduces to exhibit approximately constant delay. Furthermore, a slight increase in the value of delay for \(T_{1}\) traffic has been observed for high \(\mathrm{S_{FRAG}}\), in each of the Figure 14b-e. For the high value of \(\mathrm{S_{FRAG}}\), the interruption may occur only after transmitting a large portion of \(T_{1}\) packet. For example, if packet of \(T_{2}\) interrupts the transmission of \(T_{1}\) when \(\mathrm{S_{FRAG}}=50\) in Figure 14b, the time which was spent in transmitting the 50 B of \(T_{1}\) data would be wasted.