Framing is "G-PON like" but uses different wavelengths from G-PON (using a WDM to separate them) so that G-PON subscribers can be upgraded to 10G-PON incrementally while GPON users continue on the original OLT. The G-PON standard is G.98. This compares to the IEEE 802.3av standard for 10G-EPON based on Ethernet, which has standardised upstream rates of both 1Gbps and 10Gbps. The 10 Gigabit PON wavelengths (1577 nm down / 1270 nm up) differ from GPON and EPON (1490 nm down /1310 nm up), allowing it to coexist on the same fibre with either of the Gigabit PONs.
ITU-T Recommendation G.987 is a family that defines this access network standard (referred to as XG-PON). It comprises four recommendations:
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G.987: 10-Gigabit-capable passive optical network (XG-PON) systems: Definitions, Abbreviations, and Acronyms, 2010.
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G.987.1: General requirements of 10G-PON systems (approved 2010-01-13). Includes examples of services, user network interfaces (UNIs) and service node interfaces (SNIs), as well as the principal deployment configurations that are requested by network operators.
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G.987.2: Physical media dependent (PMD) layer specification (approved 2010-01-13, updated 2010-10-07). Describes a flexible optical fibre access network representing an evolutionary development from G.984.2, asymmetric only in the current version.
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G.987.3: Transmission convergence (TC) specifications (approved 2010-10-07).
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G.988: ONU management and control interface (OMCI) specification.(approved 2010-10-07)
