DPoE specifications have both interfaces and reference points.
7.3.1 DPoE Interfaces
Interfaces are the inputs and outputs of the separable subsystems of DPoE Elements – that is, the inputs and outputs between the OSS and the DPoE System, between the DPoE System and a DPoE ONU, and between the DPoE ONU and various types of interfaces to CPE, eDOCSIS devices, and DEMARC devices. Since DPoE Standalone ONUs can contain embedded subsystems (eDOCSIS devices) that are often built by OEMs other than the ONU vendor, the DPoE specifications include a set of interfaces within the DPoE ONU called the S1 interfaces.
7.3.1.1 D Interface
The D interface is the interface from the DPoE System to the operator's IP network for all IP traffic, including bearer traffic for IP service and OAMP functionality for IP and Ethernet services. The D interface on the DPoE System MUST support IP routing and forwarding as described in [DPoE-SP-IPNEv1.0]. The D interface is the interface for interoperability between the operator's OSS and DPoE Systems.
7.3.1.2 TU Interface
The TU interface is the interface between a DPoE System and one or more DPoE ONUs. The TU interface is the interface for interoperability between DPoE System and DPoE ONUs. Any DPoE System MUST interoperate with any DPoE ONU.
7.3.1.3 S Interface
The S interfaces and reference points, in general, represent the customer interfaces in the DPoE Network on DPoE ONUs.
7.3.1.4 S1 Interface
S1 interfaces are only on DPoE ONUs with external PHY interfaces operating as MI or MU. An S1 interface on a
DPoE Standalone ONU MAY be hardwired to an eDOCSIS device and be an LCI interface. An S1 interface on a
DPoE Standalone ONU MAY be configurable to act as an LCI on a port, as CMCI, MI, or MU interface. An S1
interface on a DPoE Standalone ONU SHOULD be capable of being configured as one and only one of: LCI, CMCI, MI, or MU. An S1 interface on a DPoE Standalone ONU MUST NOT be configured as more than one of
these at any one time. Specifications for provisioning ports for MI or MU services are in [DPoE-SP-MEFv1.0]. Specifications for provisioning ports for CMCI or LCI service are in [DPoE-SP-MULPIv1.0].
7.3.1.5 LCI Interface
The LCI interface is equivalent to an eDOCSIS Logical CPE Interface (LCI) as described in [eDOCSIS]. An S1
interface connected to an eDOCSIS device such as an eDVA, eRouter, or eDSG is always an LCI interface. An S1
7.3.2 DPoE Reference Points
Reference points are similar to interfaces in that they point to locations where there are inputs and outputs. However, reference points may either not be separable because they are inside of an element, or they may be a reference to an independent industry standard.
7.3.2.1 MN Reference Point
The logical forwarding function that connects to the physical or logical interface that provides the MEF INNI to the operator's Metro Ethernet Network (MEN) is the MN reference point in DPoE. MN is a reference point because DPoE specifications do not specify the requirements for the interface. The requirements for MN are specified in MEF, [L2VPN], and IEEE specifications. The MN reference point is used to describe the MEF bearer traffic interface on a DPoE System connecting to an operator's MEN.
7.3.2.2 S Reference Point
The S interfaces and reference points, in general, represent the customer interfaces in the DPoE Network on DPoE ONUs.
7.3.2.3 S2 Reference Point
The S2 reference point is useful for the explanation of DEMARC device interfaces. Since the DEMARC device is
not designed to DPoE specifications, the S2 reference point is informative (only for reference). DPoE ONUs do not
have access to port and interface information on DEMARC devices. 7.3.2.4 CS Reference Point
The classifier on the DPoE System is identified and described by the Classifier-System (CS) reference point. This
reference point is useful for describing classification, scheduling, and forwarding functions required for
interoperability between DPoE Systems and DPoE ONUs and for interoperability between DPoE Systems and the D and MN interface and reference points.
7.3.2.5 CO Reference Point
The classifier on a DPoE ONU is identified and described by the Classifier-ONU (CO) reference point. This
reference point is useful for describing classification, scheduling, and forwarding functions required for interoperability between the OSS or DPoE System and DPoE ONU. It is also useful for describing the same parameters between the CO reference point and the S interfaces or reference points.
7.3.2.6 MI Reference Point
The physical or logical interface that provides the MEF INNI to a DEMARC device (at a customer premise) is the MI reference point. MI is a reference point because DPoE specifications do not specify the requirements for the interface. The requirements for MI are specified in MEF and IEEE specifications. The MI reference point is used to describe the MEF bearer traffic interface on a DEMARC device, which in turn provides either another INNI (MI reference point) or MEF UNI interface (MU reference point).
7.3.2.7 MU Reference Point
An interface that provides the MEF UNI on a DPoE ONU or on a DEMARC device is the MU reference point. MU is a reference point because DPoE specifications do not specify the requirements for the interface. The requirements for MU are specified in MEF and IEEE specifications. The MU reference point is used to describe the MEF User to Network Interface (UNI) on DPoE Standalone ONUs or DEMARC devices.