of multiple MEC vendors, and there is, consequently, a need to enable com- munication between different MEC systems. For example, different MEC systems should be able to communicate, as information (e.g. PC5 V2X-relevant information, a specific service, etc.) sought by a MEC application running at a host of a given MEC system may need to be directly available to MEC platforms of other MEC systems. Additionally, the availability of critical V2X-relevant information at MEC platforms of a given MEC system should be accessible to other nearby deployed MEC systems as well, since a vehicle may pass through 6 Enabling Technologies Remote Application Server PGW 1 PGW 2 SGW 1 SGW 2 ((13)) Host 1 RAN 1 Host 2 RAN 2 Operator 1 Operator 2 Figure 6.4.8 A V2X communication setup involving two different mobile operators (Source: Reproduced with permission from © ETSI). different radio connectivity areas co-located with different MEC systems. As a result, the following issues need to be addressed: How to provide inter-MEC system communication, e.g. for V2X services, in order to enable information exposure to MEC applications, potentially belonging to different MEC systems. How to enable a secure communication among MEC applications in different MEC systems. Inspired by the above described scenario (see also the relevant clauses in MEC003), an inter-MEC system communication aims to address the following needs: A MEC platform should be able to discover other MEC platforms that may belong to different MEC systems. A MEC platform should be able to exchange information in a secure manner with other MEC platforms that may belong to different MEC systems. A MEC application should be able to exchange information in a secure manner with other MEC applications that may belong to different MEC systems. 6.4 Multi-Access Edge Computing To enable inter-MEC system communication, the following hierarchical inter-MEC system discovery and communication framework is assumed: MEC system-level inter-system discovery and communication. MEC host-level