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Question 2/15 – Optical systems for fibre access networks
(Continuation of Question 2/15)


Recommendations for point-to-point and point-to-multi point access systems, such as the G.984.x G-PON series, have allowed telecommunications manufacturers to develop, inter-operable access equipment. Practical experience with the design and deployment will necessitate revision of these Recommendations to include, for example, enhanced services, better interoperability (for example via Implementers' Guides), use of enhancement band, higher split ratios and increased capacity.

To increase service capability the use of new technologies such as wavelength division multiplexers and optical amplifiers, or new system approaches, such hybrid TDMA/WDMA systems, in the access network, will necessitate the development of new Recommendations.

Fibre access systems need to support a range of service capabilities at the edge. Wireless, wireline and fibre (e.g. G.65x and Plastic Optical Fibre (POF)) will be needed. Economies are needed for fibre access deployment to become prevalent as a mass-market solution. Demand will be driven by factors such as: the ability to carry interactive and broadcast services (e.g. residential video, HDTV), managed bandwidth to multiple Internet Service Providers (ISPs), together with higher quality of service and improved resilience. Solutions are required for a wide range of market segments and situations including: business, small-to-medium-enterprise, small-office-home-office, residential, green field, and network upgrade.

Demand for dedicated GbE and 10GbE services initially to business users is increasing. New techniques are needed to increase performance and reduce costs for both dedicated and shared bearer services. Both access and metro networks should be considered when offering such access services, because currently, access nodes are sometimes bypassed to minimize overall network cost. Both Point-to-point and point-to-multi-point solutions will be considered.

Integration of all services onto a single backhaul fibre network is an important economic consideration for network operators.

To be successful, Q2 needs to harmonize with other bodies which have a strong optical access industry role, such as IEEE and IEC. The following major Recommendations, in force at the time of approval of this Question, fall under its responsibility: G.981, G.982, G.983, G.984 and G.985 series.


What new or modifications to existing Recommendations are needed to:

  • Enable next generation PON architecture and technology to offer improved services and economics?
  • Integrate access and metro/backhaul networks into one seamless optical access and aggregation network?
  • Allow increased use of Wavelength Division Multiplexing (WDM) in optical access systems and architectures?
  • Allow optical access systems to operate at higher bit-rates?
  • Serve a mixture of optical, copper and radio (broadband) final customer connections to the same optical access system, with simplified remote electronics?
  • Allow individual customers on a live G-PON to be upgraded to higher capacity next generation systems without impacting on other users’ traffic?

What new Recommendations need to be developed to:

  • Allow systems to evolve to higher split ratios physically and logically?
  • Meet requirements for longer reach in the access network?
  • Allow full services over Ethernet (e.g., TDM over Ethernet, encapsulation techniques, Quality of Service (QoS), management of Ethernet services)?

What enhancements or new Recommendations are needed to:

  • Enable new resilience requirements to be achieved in the fibre access network; e.g. dual cards, dual parenting resilience, switchover procedures, alternative paths or drop transmission media?
  • Add new Optical Network Termination (ONT) Management Control Interface [OMCI] requirements; e.g. management systems support of new services, (e.g. configuration, fault performance) or additional attributes to existing managed entities?

What enhancements to existing Recommendations:

  • need to be defined to improve interoperability?
  • are needed to enable legacy or other services on a fibre access network; e.g. telephony, data, video?

What new or modifications to existing Recommendations are needed to enable fibre access systems to be provided which support:

  • multiple drop media?
  • carrier grade services?

What enhancements to existing Recommendations are required to provide energy savings directly or indirectly in Information and Communication Technologies (ICTs) or in other industries?

What enhancements to developing or new Recommendations are required to provide such energy savings?

Study items to be considered include, but are not limited to:

  • Next generation PON architecture and technology
  • New long-reach access system(s) for access/metro-integrated applications based on WDM access and/or enhanced TDM access technologies.
  • How to specify ONT’s for the consumer market?
  • Impact of new component technology on optical access networks.
  • How to ensure the optical systems contribute to the end-end QoS for packet services?
  • How to ensure the maximum service capability for Ethernet and Wireless Local Area Network (WLAN) edge networks?
  •  How to provide for video services?
  •  Interoperability and physical interconnect conformance.
  • The definition of access demarcation point in the light of consumer-owned optical network terminations.
  • Modulation schemes over fibre access
  • What is the service capacity and requirements outlook for access?
  • How to ensure efficient inter-connection between fibre access systems and DSL technologies?


Tasks include, but are not limited to:

  • Maintenance and enhancements of G.983, G.984 and G.985 series Recommendations with regard to capacity, interoperability, management and control interfaces, survivability, spectral management, split ratios or other requirements
  • Draft a new Recommendation on general characteristics of the new long-reach access system(s) for access/metro-integrated applications.
  • Draft one or more new Recommendation series to describe the next generations of optical access systems

NOTE: An up-to-date status of work under this Question is contained in the SG15 Work Programme at




  • G.981, G.982, G.983, G.984 and G.985 series.


  • Q1/15, Q4/15, Q6/15, Q9/15, Q11/15 and Q12/15.

Study Groups:

  • ITU-T SG2 on management aspects
  • ITU-T SG5 on hybrid fibre/copper cables for outside plant
  • ITU-T SG9 on television and sound transmission
  • ITU-T SG13 on Multi-Protocol Label Switching (MPLS) layer characteristics

Standardization bodies, forums and consortia:

  • IEC TC86 and its sub-committees on devices and other topics
  • Broadband Forum (ex DSL Forum) on network architectures and management
  • IETF on MIB
  • IEEE 802 on Optical access systems, Ethernet and WLAN
  • ATIS Committee NIPP and its subcommittee on Optical Access Networks (OAN)
  • ATIS Committee NIPP and its subcommittee on Telecom Energy Efficiency (TEE)


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