5.2.2. Case Study 2

This case study describes the implemented operation of the fault tolerance mechanism in the MAS. As explained in Section 3, the Main Container (MC) is a special node in the JADE platform that coordinates between other containers and agents hosted in these containers. In order to implement a fault-tolerant mechanism, a backup agent of the MC was created. The two main-containers are arranged in a unidirectional ring. The MC is considered as the master MC while the backup agent is considered as the slave. Once the master MC fails, the slave MC detects the failure and takes the appropriate recovery actions. Three containers were created in this case study. By default, the AMS and DF agents are affected to the master MC, which is the 'Main-Container' in our case. The 'BackupContainer' is created, and 'Container-1' hosts the MG agents. 'Mg1' is the MGO while other agents are the interoperability agents of each MG components. Figure 10 illustrates the MAS platform before and after the fault test. A manual failure event was introduced while the RT-EMS was running. Through the Jade user interface, the MC was terminated. Automatically and instantaneously, the backup agent detects the event, changes its status to the new master MC and transfers the AMS and DF from the faulty MC to its container. As a consequence, the list of all alive agents and containers in the multi-agent platform remain updated and the RT-EMS continues its normal operation.

**Figure 10.** Fault tolerance mechanism in the JADE platform.
