Chapter 3: Integrated fuzzy reasoning and neural networks to enhance performance
2.6. Simulation and evaluation of effectiveness of FLRED mechanism and FLREM
Simulation of AQM mechanisms is implemented on NS2 software [40], this software is most widely used, trusted and recognized by the research community [46] [55] [58].
2.6.1. Setting and simulation of FLRED mechanism and FLREM mechanism 2.6.1.1. Programming for FLRED mechanism and FLREM mechanism
The program for FLRED and FLREM includes files of FLRED.h, FLRED.cc, FLREM.h and FLREM.cc; presented in Appendix
2.6.1.2. Process of simulation and evaluation of AQM mechanisms 2.6.1.3. Criteria for performance evaluation of AQM mechanisms
2.6.2. Stability evaluation of FLRED mechanism and FLREM mechanism 2.6.2.1. Single receptor network model
Router A Router B
(C1,d1)
(C2,d2) (C3,d3) N Sources
Destination N lines
Figure 2.17. Single receptor simulation network model 2.6.2.2. Queue control of FLRED mechanism and FLREM mechanism
The simulation results of the mechanism based on queue length are RED, FEM and FLRED shown in Figure 2.18 and Figure 2.19, indicating the improved RED mechanism using fuzzy control as FEM and FLRED which are always able to control the queue more stable than the traditional RED mechanism thank to the fuzzy controller of the mechanisms controlling queue based on reference queue that means making the instantaneous fluctuating around the reference queue (200 packets).
Figure 2.18. Queue control of RED and FLRED
In addition, the graph of Figure 2.19 shows that FLRED mechanism has range (less than 70 packets) smaller than FEM mechanism (more than 100 packets).
Figure 2.19. Queue control of FEM and FLRED
Similarly, fuzzy controller (FUZREM, FLREM) are used when simulating REM mechanism and improved REM mechanism, results in Figure 2.20 and Figure 2.21 show REM mechanism of queue control are not stable, range of REM queue length is more than 150 packets. In contrast, FUZREM and FLREM mechanisms can maintain the instant queue length at network nodes rather stably, range of queue length of these two mechanisms is less than 100 packets.
Figure 2.20. Queue Control of REM and FLREM
The graph of Figure 2.21 shows the comparison of queue control of FUZREM and FLREM mechanisms. Because FLREM uses Fuzzy Sugeno with 9 bell-shaped functions as fuzzy input values, the precision is increased and queue range of FLREM is less than 50 packets. This makes FLREM has queue stability better than FUZREM with range more than 70 packets.
Figure 2.21. Queue control of FUZREM and FLREM
The results of foregoing simulation and analysis show that queue length control efficiency of mechanisms are better and better when using traditional fuzzy controller and adaptive fuzzy controller to improve active queue management mechanisms.
2.6.2.3. Responsiveness of FLRED and FLREM mechanisms
Response of queue management mechanisms is based on queue length shown in Figure
2.22 and Figure 2.23. It also shows stable levels of queue length of the mechanisms using fuzzy logic compared to the mechanisms not using fuzzy logic. RED mechanism needs 20 seconds to stabilize the queue while reducing half of passes at the 40th second, the number in FEM is 10 seconds and FLRED is 6 seconds. In case of increased load on the network, by increasing the number of connections to 100 at 70 seconds, RED mechanism needs more 10 seconds to stabilize, FEM mechanism needs 5 seconds and FLRED mechanism needs 3 seconds.
Figure 2.22. Responsiveness of RED and FLRED
The Graph of Figure 2.23 shows the quick responsiveness of FEM and FLRED mechanisms when the network environment changes over time. Accordingly, FLRED mechanism has response times less than FEM mechanism when load increase as well as load decrease. In addition, the range of FLRED mechanism is lower than FEM mechanism, in all the circumstances of load change. This has shown effectiveness when using Fuzzy Sugeno with the bell-shaped function and adaptable components in FLRED mechanism.
Figure 2.23. Responsiveness of FEM and FLRED
Similarly, Figure 2.24 and Figure 2.25 show responsiveness of the queue management mechanisms based on queue length and traffic load.
Figure 2.24. Responsiveness of REM and FLREM
On the other hand, the Graph of Figure 2.25 shows, the decrease or increase of connection flow to the network, the recovery time to the steady state at the reference queue length of FLREM mechanism less than FUZREM mechanism, when load increase as well as load decrease. In addition, in the case of connection flow change, the range of FLREM (100 packets) is less than FUZREM (over 100 packets).
Figure 2.25. Responsiveness of FUZREM and FLREM
Basing on the results of the simulation settings and graph figures show that responsiveness of the active queue management mechanisms is accelerated, while the queue management mechanisms using traditional fuzzy controller and adaptive fuzzy controller in turn are set at network nodes.
2.6.3. Performance evaluation of FLRED mechanism and FLREM mechanism 2.6.3.1. Multi-receptor network model
Router A (a Mbps, g ms)
Sources N lines
Router B Destination
M lines
Send Receive
(a Mbps, g ms)
(a Mbps, g ms)
Figure 2.26. Multi-receptor simulating network model
2.6.3.2. Evaluation of packet loss ratio of FLRED mechanism and FLREM mechanism
Figure 2.27. Packet loss ratio of AQM mechanism
This result is consistent with the working principles of the traditional fuzzy controllers and
adaptive fuzzy controllers. With adaptive fuzzy control, in addition to using Fuzzy Sugeno, there is also an adaptive mechanism to adjust the packet marking probability matching the network changes.
2.6.3.3. Evaluation of transmission line using level of FLRED and FLREM
Basing on the graph, it is shown that the improved mechanisms (FEM, FUZREM, FLRED and FLREM) has packet loss ratio lower than the traditional mechanisms (RED and REM).
Figure 2:28. Transmission line using level of AQM mechanism
In all cases, RED mechanism always has the min transmission line using level and FLREM mechanism always has the max transmission line using level. This result thanks to the criterion convergence of FLREM mechanism when processing the packets to the network nodes. Besides, the succession of REM mechanism when considering the influence of the queue length and packet flow, FLREM mechanism is also improved by adaptive fuzzy controller, while RED only uses queue length element to calculate the packet marking probability.