G.987

G.987
Name	G.987
Status	Published
Organization	International Telecommunication Union Telecommunication Standardization Sector
Abbreviation	ITU-T G.987
Domain	Optical access networks
First published	2005
Latest revision	2012

G.987

G.987 is an ITU-T recommendation specifying standards for next-generation optical line terminals and optical network units in passive optical networks. It defines physical layer, transmission convergence, management, and coexistence mechanisms for fiber-to-the-home and fiber-to-the-premises deployments. The recommendation aims to interoperate with existing deployments and coordinate with other standards bodies for broadband access evolution.

Overview

G.987 addresses requirements for optical access technologies used by major vendors and operators such as Alcatel-Lucent, Nokia, Huawei Technologies, Cisco Systems, ZTE Corporation and Ericsson. It complements related standards from the Institute of Electrical and Electronics Engineers and the International Organization for Standardization while aligning with spectrums and wavelength plans similar to those in recommendations by ITU-T and regional bodies like European Telecommunications Standards Institute. The scope includes physical interfaces, optical budget, wavelength allocation, and mechanisms for coexistence with legacy systems deployed by carriers such as BT Group, NTT, Verizon Communications, AT&T Inc. and Deutsche Telekom.

Technical Specifications

The specification details optical line rate, channelization, and framing formats used in deployments by vendors like PON Manufacturers Association members and integrators working with operators including China Mobile and SK Telecom. It enumerates wavelength plans comparable to those used in GPON and defines power budgets that network equipment from Broadcom Inc. and MediaTek must meet. The recommendation specifies forward error correction, clock recovery, and jitter tolerance similar to mechanisms in IEEE 802.3 standards and interoperable with transport gear from Ciena Corporation and Nokia Siemens Networks. It mandates management interfaces analogous to those used in TR-069 and data models that can be integrated into OSS platforms from Oracle Corporation and IBM.

Architecture and Components

G.987 defines an architecture comprising an optical line terminal (OLT), optical network units (ONUs), splitters, and feeder and distribution fibers deployed by utilities and municipalities such as City of London Corporation and metropolitan authorities in Tokyo or Seoul. Component specifications reference transceiver modules, tunable lasers, and photodiodes provided by suppliers like Finisar, II-VI Incorporated, and Sumitomo Electric. Control plane functions, provisioning, and policing mechanisms align with systems used by Verizon Business and Orange S.A., and the physical topology supports point-to-multipoint topologies as seen in projects by Google Fiber and municipal broadband initiatives. The architecture incorporates optical distribution network design practices adopted in large deployments by Comcast and regional carriers like Rogers Communications.

Performance and Testing

Performance metrics include throughput, latency, packet loss, and optical signal-to-noise ratio measured during interoperability testing at laboratories operated by ETSI and academic centers such as Massachusetts Institute of Technology and Tsinghua University. Conformance test suites reference test equipment vendors like EXFO Inc. and Viavi Solutions and make use of channel emulation techniques similar to those in IETF tests. Scalability assessments consider splitter ratios and subscriber density scenarios encountered by carriers like Telefónica and NTT East; reliability testing follows procedures used by Underwriters Laboratories for environmental and lifecycle validation. Field trials coordinated with municipal partners and operators such as KDDI and Singtel validate provisioning speed and fault-recovery mechanisms.

Implementations and Deployment

Commercial implementations have been released by hardware vendors including Huawei, ZTE, Alcatel-Lucent, Nokia, and system integrators partnering with service providers like Vodafone Group and Telefonica for residential and business services. Deployment strategies mirror those used in large-scale rollouts by China Telecom and BT Openreach, including fiber roll-out planning, trenching contracts with firms like Skanska and Vinci, and regulatory coordination with authorities such as Federal Communications Commission and European Commission. Software stacks implement management features compatible with platforms from HP Enterprise and Dell Technologies, and interoperability labs run by consortia such as Broadband Forum perform multi-vendor validation.

History and Development

The recommendation emerged from study groups within the ITU-T responding to increasing bandwidth demands from services provided by Netflix, YouTube, Amazon Web Services, and cloud operators. Early drafts incorporated input from research institutions including Bell Labs and Bellcore, and hardware vendors collaborated with operators such as NTT and Telefónica to shape scalability and coexistence requirements. Subsequent revisions aligned with technological advances driven by semiconductor suppliers like Intel Corporation and Qualcomm Incorporated, and with policy influences from governmental programs in the United States Department of Commerce and national broadband plans in Japan and China. Adoption accelerated in the late 2000s and 2010s as fiber access became central to competition among incumbents and new entrants including Google Fiber and regional utilities.

Category:ITU-T Recommendations