## 5 Discussion and Future Work  
In this tutorial, a structured way of performing interoperability tests has been introduced. A use case in the field of demand side management has been presented, which describes the interaction of many actors in the full chain from the energy provider to the customer. The methodology steps have been followed: use case description and representation on the SGAM; BAP creation and the importance of defining the standards that can be used in each link; BAIOP creation and description of the test steps. \begin{table}
\begin{tabular}{p{142.3 pt} p{284.5 pt}} \hline \hline
**Test Case ID** & T DSM/DR2 \\ \hline
**BAIO ID/UC ID** & IU1/DSM/DR1 \\ \hline
**Interoperability Layer** & Information \\ \hline
**Summary of the Test** & One new residential smart meter (end-user) is added to the system. The new smart meter has connected loads similar to the rest residential consumption profiles. \\ \cline{2-3}  & The new smart meter should be recognised by the data concentrator and communication should be established. As further steps, Actor B should monitor the daily consumption, gather the data and forward it to Actor A. Messages should be sent to the end-user for his/her participation to the DSM/DR program Actor A should control the CEMS within the home. \\ \hline
**Test Purpose** & To test the integration of a new end-user (new smart meter) in the system \\ \hline
**Test Description** & \\ \hline
**Step 1** & The EUT is a new smart meter added to the test bed and connections are done correctly. \\ \hline
**Step2** & The EUT has connected loads, which function normally, so, energy is flowing without problems. \\ \hline
**Step 3** & The data concentrator is set to accept packets from the new smart meter; the EUT is configured so as to accept data from the data concentrator. For this purpose, the MAC and/or IP addresses of the two devices are required as well as suitable authorisation (passwords) so as to enable the parameters setup. \\ \hline
**Step 4** & The communication between the smart meter and the data concentrator needs to be established: A PASS verdict of the test on the communication layer is required for this interoperability test to proceed. \\ \hline
**Step 5** & Test Verdict: PASS: in case Actor B can monitor and control the new smart meter; access to its values is available through the software; the interpretation and demonstration of information through the software takes place; the smart meter accepts commands from the data concentrator. FAIL: otherwise. \\ \hline \hline \end{tabular}
\end{table} 
Table 11: BAIOP for the information layer. Each step of the methodology entails a certain difficulty, from which limitations can be derived:
* The use case description needs to be performed so as to include all actors involved and the mapping on the SGAM needs to be done correctly, otherwise links of interactions may not be included in the further analysis. * It is essential to define all possible standards that can be used in each link of interaction between actors. At this step, not only is it crucial to define the standard to be used in the link of interest, but also specific options within the standard need to be defined. For example, specific equipment under test can be operating with a specific option of a standard, whereas the rest of the testbed can be operating with a second option of this standard. As a result, the system is theoretically interoperable, but in reality this is not the case. Such an issue can result in inconsistencies and misleading assumptions. * The step tests need to be precisely defined in the BAIOP creation; otherwise the verdict cannot be derived correctly. Furthermore, the stepwise procedure is a way to breakdown the experiment so that it is better monitored and controlled, the interoperability issues can then more easily tracked. The methodology also describes the statistical design of experiments and statistical analysis of results.