## 3 Integration of Multi-Domain MEC Environments
### Host Interconnection in MEC  
MEC natively considers the possibility of integration with other multi-access edge hosts through the Mp3 reference point. This reference point between multi-access edge platforms is intended to be used for control interconnection between Multi-access Edge Platforms (MEPs) of both a local and a remote Multi-access Edge Hosts. Such remote MEH could pertain, in principle, to a different administrative domains, even though this is not detailed in MEC specifications. Mp3 allows for supporting mobility in an MEC system, in order to enable continuity of the service and facilitating relocation or mobility of an application (including application-specific user-related information). Functional details with respect to gaps to be supported in this reference point have been described in [29]. The implication of this interconnection is further elaborated in Section 5. However, there could be additional multi-domain dimensions, not addressed by the ETSI MEC specifications. For instance, there could be third party infrastructure owners that could interconnect their assets with MEC operators in order to increase the coverage footprint. Similarly, there could be also the case that application owners would require to make use of the capabilities from different (and complementary) MEC operators to increase their coverage. It seems clear that a single operator will not be able to cope with all the necessary infrastructure for providing continuous stratum of edge computing even in a single country. It can be expected that a variety of providers start to emerge offering some of that capabilities because of different reasons (e.g., municipalities covering monumental areas, tower companies leveraging on their assets at the very edge, private networks monetizing excess capacity, hyperscalers entering the MEC business, local micro operators deployed in specific geographical areas, big operators pursuing global coverage, etc.). All of these situations present commercial options that could enable new business models. For instance, very recently the GSMA \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Reference Point**[27] & **Components Involved** & **Scope** \\ \hline \multirow{8}{*}{**MEC**} & Mm1 & OSS-MEO & Instantiation and termination of multi-access edge applications in the MEC system. \\ \cline{2-4}  & Mm2 & OSS-MEPM & Configuration as well as fault and performance management of the MEC platform manager. \\ \cline{2-4}  & Mm3 & MEO-MEPM & Lifecycle management of applications, including application rules and requirements. \\ \cline{2-4}  & Mm4 & MEO-VIM & Management of virtual infrastructure resources per host. \\ \cline{2-4}  & Mm5 & MEPM-MEP & Configuration of the platform, the application rules and their requirements, including application lifecycle. \\ \cline{2-4}  & Mm6 & MEPM-VIM & Management of virtual infrastructure resources to support the application lifecycle management. \\ \cline{2-4}  & Mm7 & VIM-NFVI & Management of the virtualization infrastructure. \\ \cline{2-4}  & Mm8 & OSS-UE LCM & Support of UE application requests for running application in the MEC system. \\ \cline{2-4}  & Mm9 & MEO-UE LCM & Management of applications as requested by UE application. \\ \cline{2-4}  & Mm1 & OSS-CFS portal & Third parties requests for running applications in the MEC system. \\ \cline{2-4}  & Mx2 & UE app-UE LCM proxy & UE application requests for running (or moving) applications in the MEC system. \\ \cline{2-4}  & Mp1 & MEP-ME app & Service registration and discovery, as well as their communications support. It can also provide additional functionality such as traffic rules and DNS rules activation. Finally, it serves for consuming service specific functionality to external applications. \\ \cline{2-4}  & Mp2 & MEP-NFVI & Data plane control for routing traffic among applications, networks, services, etc. \\ \cline{2-4}  & Mp3 & MEP-other MEP & Control communication between MEC platforms from different hosts. \\ \hline \hline \end{tabular}
\end{table}