# Tunnel-Free Distributed Mobility Management (DMM) Support Protocol for Future Mobile Networks
## 4 Results and Discussion
### Handover Blocking Probability  
For comparison purposes, the values of velocity \(v\) and radius \(R\) were set to 20 m/s and 500 m, respectively, whereas the value of \(\rho_{f}\) varied from 0 to 0.7 with a step value of 0.05. Figure 6 shows the handover blocking probability for each mobility management protocol. For this analysis, the handover latency was considered as a blocking factor for the handover blocking probability. Synonymous with the previous result in Figure 5, an increase in the value of \(\rho_{f}\) consequently increased the handover blocking probability. The handover blocking probability of the proposed TFMIPv6 was lower than all the other protocols, while that of MIPv6 was higher than all the other protocols. Again, this analysis placed PMIPv6 second in terms of the handover blocking probability.  
For comparison purposes, the values of \(\rho_{f}\) and \(R\) were set as 0.2 and 500 m, respectively, whereas the value of \(v\) varied from 0 to 30 m/s. Figure 7 shows the handover blocking probability versus \(v\). With an increase in \(v\), there were frequent changes in the MN's point of attachment, which implied that it was necessary for a MN with a higher velocity to complete its handover in less time than the MN with a lower velocity. Therefore, the increase in the velocity consequently increased the handover blocking probability for each mobility management protocol. In the simulation, the proposed TFMIPv6 outperformed the other mobility management protocols in terms of the handover blocking probability, which was below 0.05 even with an increase in velocity up until 30 m/s. PMIPv6 again placed second  
Figure 5: Handover latency versus \(\rho_{f}\).  
Figure 6: Handover blocking probability versus \(\rho_{f}\).  
in terms of the handover blocking probability with a value below 0.1 when the velocity reached 30 m/s. Synonymous with the earlier results, MIPv6 performed poorly yet again in terms of the handover blocking probability.  
Furthermore, for comparison purposes, the values of \(\rho_{f}\) and \(v\) were set to 0.2 and 20 m/s, respectively, whereas the value of \(R\) varied from 400 to 800 m. The handover blocking probability versus \(R\) is shown in Figure 8. An increase in the value of \(R\) meant a bigger access network for the MN, which consequently increased the residence time for a MN to stay in that access network, giving the MN more time to complete its handover process, hence decreasing the handover blocking probability. As can be seen in Figure 8, \(R\) influenced most of the mobility management protocols but not the proposed TFMIPv6.  
All the results presented in Figures 6-8 show that the handover latency of the proposed TFMIPv6 was minor enough to not to be influenced and affected by the handover blocking problems caused by \(\rho_{f}\), \(v\), and \(R\). The reason for the extraordinary performance of the proposed TFMIPv6 in comparison with the other protocols was the tunnel-free approach introduced, along with the MBB approach discussed earlier. The MBB approach allowed the MN to prepare its handover at the previous BMA before the MN performed the actual handover to the new BMA, meanwhile continuing the previous  
Figure 8: Handover blocking probability versus \(R\) (m).  
Figure 7: Handover blocking probability versus \(v\) (m/s).  
ongoing session anchoring through the new BMA instead of the previous BMA, hence eliminating the need for tunneling.