scope:

This Recommendation defines the interfaces of the Ethernet transport network to be used within and between subnetworks of the Ethernet network, in terms of Ethernet transport hierarchy, formats for mapping and multiplexing client signals into Ethernet connections and formats for multiplexing Ethernet connection signals into Ethernet or non-Ethernet connection signals. These interfaces support the transport of Ethernet services, so-called Ethernet virtual connection (EVC) services, as defined in [ITU-T G.8011]. The Ethernet connections support e-Line, E-Tree and E-LAN Ethernet services as defined in [ITU-T G.8011].

This Recommendation specifies the interworking aspects between EVC service signals on an Ethernet user-to-network interface (UNI) and Ethernet connection signals on an Ethernet network-to-network interface (NNI).

This Recommendation does not specify the Ethernet component and/or equipment models to meet the Ethernet NNI. Those components and models are defined in [ITU-T G.8021] and [ITU-T G.8021.1].

The interfaces defined in this Recommendation can be applied at NNIs and UNIs of the Ethernet transport network. The Ethernet UNI is formed by an Ethernet interface and the Ethernet NNI by an Ethernet interface or an Ethernet over Transport interface. The Ethernet over Transport NNI uses various server layer networks like optical transport hierarchy (OTH) and SDH. [ITU-T G.8012] describes the mapping of ETH_CI into those server layers mainly for Ethernet private line applications. This Recommendation describes the mapping of S-EC, B-EC, BS-EC, L-EC and ESP signals into those server layers for an Ethernet transport network application which deploys a mix of ETY and OTH server layers. It is recognized, for Ethernet over Transport interfaces used within Ethernet subnetworks, that aspects of the interface are transport technology dependent. The transport technology dependent aspects are defined in the transport technology specific Recommendations, e.g., [ITU-T G.709] and [ITU-T G.707].

The operations, administration and maintenance (OAM) functionality necessary for operations and management of Ethernet subnetworks is described in [ITU-T G.8013]. The detailed requirements are specified in a number of ITU-T Recommendations, IEEE Standards and MEF Technical Specifications, which are referred to. This Recommendation provides a description of the applicability of Ethernet OAM to the different types of Ethernet connections. Note that [ITU-T G.8012] was developed prior to [ITU-T G.8013] and did not discuss Ethernet OAM.