ications. MEC uses the NFV infrastructure management entity where possible. The two architectures (standalone and NFV-based) depicted in Figures 6.4.1 and 6.4.2 are similar; however, there are some differences, which are introduced in the "MEC in NFV" variant, specifically: The Mm3* reference point between MEC application orchestrator (MEAO) and MEC platform manager - NFV (MEPM-V) is based on the Mm3 reference point. The Mp1 reference point between an MEC application and the MEC platform is optional for the MEC application, unless it is an application that provides and/or consumes a MEC service. The MEC orchestrator (MEO), as defined in the MEC reference architecture (ETSI GS MEC 003), is replaced by a MEAO that uses the network function virtualization orches- trator (NFVO) for resource orchestration and for orchestration of the set of MEC app VNFs as one or more NFV network services. The MEPM, as defined in the MEC reference architecture (ETSI GS MEC 003), is replaced by an MEPM-V that delegates the life cycle management (LCM) part to one or more VNFM(s). portal Operations support system (OSS) Device Os-Ma-nfvo proxy MEC application orchestrator (MEAO) Or-Vnfm Or-Vi Other platform MEC app platform rules & Ve-Vnfm-em MEC platform element (VNF) MEC platform Service (MEC app manager NFV platform (MEPM-V) MEC App (VNF) Ve-Vnfm-vnf Nf-Vn Nf-Vn Data plane Vi-Vnfm=l Mm6 (VNF/PNF) Nf-Vi Virtualization infrastructure manager (VIM) NFV reference points MEC reference points MEC-NFV reference points Mv1 - related to Os-Ma-nfvo Mv2 - related to Ve-Vnfm-em Mv3 - related to Ve-Vnfm-vnf Figure 6.4.2 MEC reference architecture: variant for MEC in NFV (Source: Reproduced with permission from © ETSI). 6 Enabling Technologies 6.4.3.2 ETSI MEC APIs Having use case-driven requirements as a starting point (MEC002), the ETSI MEC Industry Specification Group (ISG) has defined a reference architecture in Group Specification MEC 003 (MEC003) and a set of APIs for key MEC interfaces. These include specifications related to the essential fu