CHAPTER 4 4. Simulation procedure 4.1 Introduction The main aim of this chapter is to discuss the simulation procedure followed in evaluating the performance of AODV under black hole attacks. As discussed in the previous chapters OPNET modeler is used as the simulation tool and three scenarios are created. First scenario has normal mobile ad hoc network with AODV as routing protocol and works under ideal working conditions. Second scenario has Balckhole attacks and the third scenario is used to analyze and improve the performance of AODV. The actual simulation setup used and the procedure followed to create the required scenarios is given in this chapter as below. 4.2 Mobile Ad hoc network setup for normal scenario As discussed Mobile ad hoc network is used for evaluating the performance of AODV routing protocol under black hole attacks and thus in this context a simple MANET is simulated using OPNET. Following steps are followed to create the basic MANET 46
A new project is chosen from the file menu and a blank scenario is used to create the first scenario Campus is chosen as the required network scale and the size is set to 1000X1000 meters and thus now the MANET operates within a campus MANET is chosen as the model family from the list of models available with OPNET modeler Now a blank workspace is created and the required objects can be used for the simulation from the object palette and a typical object palette provided with OPNET modeler is as given below 47
From the above screen it can be observed that there are number of objects for MANET simulation and few of them are used across this scenario and they are as listed below 48
Wireless LAN mobile workstations are used as the mobile clients and in this scenario a total of 26 mobile nodes are used[43]. They are dragged from the object palette towards the workspace Application configuration is used to set the applications used across the network and in this scenario FTP and Web applications are used. Profile configuration object is used to set the required profiles for the applications and detailed configuration details are discussed in the later sections Mobile configuration object is used to set the mobility profiles for all the mobile nodes and a detailed configuration is discussed in the later sections[2,12,44]. Above listed objects are used for the simulation of the MANET and the detailed configuration settings done are as explained below 4.2.1 Application Configuration definitions Application configuration object is used to define the required applications that generate the traffic over the network. Application configuration object has an option to create any number of applications and in this simulation two applications 49
are used like FTP (File Transfer Protocol) and Web. Required configurations are used to set the applications and the corresponding screenshot is as given below From the above graph it can be understood that there are two applications used like FTP where medium load is imposed over the network and for the Web application a simple HTTP is used with heavy browsing[45]. Once the required applications are create now the corresponding profiles should be created to support the application traffic and the corresponding procedure followed in this context is as given below 50
4.2.2 Profile configuration settings There are two applications across the network and to generate the required application traffic corresponding profiles need to be created. Profile configuration object is used to create the profile and as there are two application two profiles are created and the corresponding screenshot is as given below From the above screen it is clear that there are two profiles like FTP and Web and the corresponding settings are done. Start time offset for both the profiles is set to a 51
constant value of 100 seconds and duration is set to end of simulation. Once the profiles are created now all the mobile nodes and the wireless LAN server should support the corresponding application traffic and the configuration are explained in the later sections.[46] 4.2.3 Mobility configuration Mobility configuration is required to set the mobility patterns for all the 26 mobile nodes used across the simulation. There are number of mobility models available for simulation and in this scenario default random way point mobility is used and the corresponding screen is as given below 52
From the above screen it is clear that default random way point is used as the required mobility model for the mobile nodes. Speed of the mobile nodes is set o a constant value of 50 seconds, pause time I set to 0 seconds, start time is set to a constant value of 15 seconds and the stop time is till end of the simulation. Once the mobility model is set for the mobile nodes across the network now the nodes should support the mobility and the corresponding procedure is as explained below 53
4.2.4 Mobile nodes and wireless LAN server configurations As discussed in the previous sections there are 26 mobile nodes and a single wireless LAN server and these mobile nodes acts as application clients and WLAN server acts as application server. For communication among these clients and server always a protocol is required and in this simulation AODV is used as the required routing protocol. The actual procedure followed in this context is given in the below screen[47]. From the above screen it is clear that AODV is used as the ad hoc routing protocol. All the mobile nodes and the wireless LAN server are selected and similar settings are done. Now all the nodes and server communicates using the AODV protocol and as the main aim of this simulation is to evaluate the performance of AODV under Balckhole attacks the corresponding AODV attributes are modified due to the attacks in the next scenario. In this scenario default AODV routing protocol 54
parameters are used. Once the AODV routing protocol is set for the simulation now the next process is to assign the application traffic to the mobile nodes and the procedure followed in this context is given below Deploy defined applications option is chosen from the protocols application menu All the mobile nodes are deployed towards the FTP and Web clients and the wireless LAN server is assigned to both the FTP and HTTP server and the corresponding screenshot is as given below[48]. 55
From the above screen it is clear that all the mobile nodes are assigned to source of both the FTP and Web profiles and the WLAN server is assigned to FTP and Web server. Now the mobile nodes act as the FTP and Web clients and the WLAN server acts as both the FTP and Web server. Now all the mobile nodes should support the mobility model created across the mobile configuration object and the corresponding procedure is shown in the below screenshot[49]. Set mobility profile is used to set the mobility defined across the mobile configuration and as the mobility used is default mobility all the mobile nodes now follow the corresponding mobility patterns. Once the basic network setup is ready the corresponding network is as shown below 56
4.2.5 Performance metrics As the main aim of this simulation is to evaluate the performance of AODV under Black hole attacks evaluation of performance is required. OPNET provides options to evaluate the performance across global level, node level and link level and in this simulation global level metrics are chosen and the corresponding screenshot is as given below 57
From the above screen it can be observed that four levels of performance metrics are chosen for this simulation like AODV, FTP, HTTP and wireless LAN and the actual values used in here are as given below[50]. Following are the performance metrics used for AODV routing protocol 58
Number of hopes per route Route discovery time Routing traffic received and sent in bits per sec and packets per sec Total acknowledgments and cache replies sent Total packets dropped Total replies sent from destination Total route errors sent Total route replies sent Total requests sent Following are the performance metrics used for FTP application Download response time Total traffic sent and received in bytes per sec and packets per sec Upload response time Following are the performance metrics used for HTTP application Object response time Page response time Traffic sent and received in bytes per sec and packets per sec Following are the performance metrics used for Wireless LAN server 59
Data dropped Delay Load Medium access delay Network load Retransmission attempts Throughput Once the required simulation metrics are chosen first scenario is ready to simulate and the procedure followed to create the second scenario is as given below 4.3 Blackhole attacks scenario First scenario is duplicated to create the second scenario and the main aim of this scenario is to impose Blackhole attacks across the network[51]. As it is not possible to impose physical attacks over the network required configuration changes are done for creating the simulated Blackhole attacks. In general when there are some Blackhole attacks over the network behavior of the AODV routing protocol is altered against the configuration details. Following are few changes made to the parameters of AODV routing protocol and the corresponding screenshot is as given below 60
From the above screen it is clear that route discovery parameters, active route timeout, hello interval loss, allowed hello loss and other parameters are altered when compared to first scenario. Few changes are also made to wireless LAN server parameters and they are as given below 61
With this configurations simulation of Blackhole attacks over the MANET is done and the third scenario is used to improve the performance of AODV and the configurations changes made are discussed in the next section 4.4 AODV performance scenario This scenario is used to improve the performance of AODV under Blackhole attacks and this scenario is created by duplicating the second scenario. 62
Configuration changes are made to AODV routing protocol parameters and Wireless LAN parameters and they are shown below Above are change changes made to AODV routing protocol parameters and with these configurations overall performance of MANET network and AODV is improved under Blackhole attacks as well. Following are the changes made to wireless LAN parameters and thus performance of application server is also improved and thus the overall performance of applications as well 63
Once all the three scenarios are created simulation is run for 1 hour and manage scenarios option is used. Similar performance metrics are used for all the three scenario and the manage scenario screen is as shown below 64
Once the simulation is done results are compared for performance evaluation and a detailed discussion is done in the next chapter[52,53]. 4.5 Running the simulation Main aim of this simulation is to evaluate and improve performance of AODV routing protocol under Blackhole attacks. Mobile ad hoc network (MANET) is simulated using OPNET modeler and three scenarios are created. First scenario has normal MANET working conditions with AODV routing protocol, second scenario has Blackhole attacks and third scenario has improved AODV working conditions. AODV routing protocol parameters and wireless LAN parameters are configured 65
to simulate the Blackhole attacks and same parameters are used to improve the AODV performance and overall network and application performance. Performance metrics are chosen at AODV, FTP, HTTP and Wireless LAN server level and the simulation is run for one hour to evaluate the results and they are discussed in the next chapter[54]. 66