## 4 Integration of FamiWare and INTER-TRUST
### FamiWare with Security for the ITS Case Study  
Now that we have integrated FamiWare and INTER-TRUST, we can generate a VSpec tree configuration of the FamiWare family for the different nodes of our ITS case study (_i.e._, the vehicle sensors and devices, the road sensors, the RSU devices and the central server). Focusing on security, each device in the ITS case study has different necessities with regard to its security level. They also have different necessities regarding the reconfiguration of the security at that device.  
Figure 8 shows a configuration of the VSpec tree for our case study. It is not complete so as to focus only on showing the different security levels that can be configured for each node of the network. Concretely, we have provided details for three different kinds of devices. An example of the first type of device is the weather sensors at the left-hand side of Figure 8. These sensors are highly constrained devices installed in the roads in order to obtain precise information about the weather conditions. This information allows the adaptation of the speed to the changes in the weather. The information provided by these sensors is critical from a security point of view, since an intruder could change it to indicate a sunny day when really it is raining, causing an accident if the speed limit is increased in bad weather conditions. This could be avoided by cyphering the information sent by the weather sensors as is shown in Figure 8, where the security/DataSecurity/cypher features have been selected. However, no reconfiguration support of any kind is going to be provided for these devices, and thus, the FamiWare services for reconfiguration were not selected.  
An example of the second type of device is the traffic cameras. These are also constrained devices where the security is critical. First, only authorized users will receive the information transmitted by the cameras. Second, all of the information transmitted by the cameras must be encrypted. In order to deploy the required security level in the traffic cameras, the access control/authorization and the DataSecurity/cypher features need to be selected for this specific configuration. Note that only four features from the security variability model defined in Figure 6 have been selected to configure the security level of the traffic cameras. The application developer has considered that in order to avoid the consumption of battery and memory in traffic cameras, these devices will be deployed with an initial  
Figure 8: Intelligent transport system (ITS) case study variability model.  
security configuration that will not be changed at runtime. Thus, among the services deployed for these devices, the INTER-TRUST modules will not be deployed. However, the difference with the weather sensors is that, in the traffic cameras, other resources, such as the battery, can be monitored (by the monitoring service) and could be reconfigured at runtime (by the reconfiguration service) according to the contextual information received (by the context awareness service).  
Finally, an example of the third type of device is the vehicle's OBU. These devices have more resources, and thus, a security solution that can be dynamically reconfigured at runtime can be deployed with fewer limitations on the consumed resources. Thus, in Figure 8, we can see how, under the services of the OBUs, all of the modules provided by INTER-TRUST in order to negotiate and reconfigure the security level of applications will be deployed. Moreover, a large set of security concerns, including authentication, authorization, encryption of data and privacy, are deployed in these nodes.