... Dense Wavelength Division Multiplex E- LAN Ethernet LAN E- LINE Ethernet Line EPL Ethernet Private Line EP-LAN E- Tree EVC Ethernet Private LAN Ethernet Tree Ethernet Virtual Connection EVPL Ethernet ... Subscriber Services Networks (e. g., ATM, FR, IP) UNI Service Interworking NNI UNI Subscriber MAN- E Metro Area Network ETHERNET (MAN- E) Service Provider X Network Interworking NNI Service Provider ... Z1 External NNI External NNI Ethernet Wide Area Network (E- WAN) Service Provider Y MAN- E Service Provider Z2 Other L1 Transport Networks (e. g., SONET, SDH, OTN) UNI Subscriber Network Interworking...