MEF 33 is a specification document developed by the Technical Committee of the MEF that defines Ethernet Access Services.
"This document defines Ethernet Access Services, which are OVC-based Ethernet services in contrast to the EVC-based services which are defined in MEF 6.1 Technical Specification “Ethernet Services Definitions”. This document uses the UNI service attributes and parameters options defined in the MEF 6.1 and ENNI and OVC service attributes defined in MEF 26 Technical Specification “External Network Network Interface (ENNI) – Phase 1”  and applies them to create new Ethernet access services between a UNI and an ENNI. These new carrier-to-carrier Ethernet access services enable Ethernet Service Providers to reach out-of- franchise customer locations through an Ethernet Access Provider's network, and deliver E-Line and E-LAN service types end to end. This document defines the UNI, OVC, OVC per UNI, OVC End Point per ENNI, and ENNI requirements for point-to-point OVC-based Ethernet services. In addition, an informative appendix is provided showing use cases of some of the defined services."