This standard describes the system-level requirements needed to provide service-level, multi-vendor interoperability of Ethernet Passive Optical Network (EPON) equipment. The specifications complement the existing IEEE 802.3(TM) and IEEE 802.1Q(TM) standards, which enable the interoperability at the Physical Layer and Data Link Layer. Specifically included in this specification are: - 25G-EPON and 50G-EPON system-level interoperability specifications covering equipment functionality, traffic engineering, and service-level quality of service/class of service (QoS/CoS) mechanisms; - Management specifications covering equipment management, service management, and power utilization.