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SG 15 at a glance (Study Period 2009 - 2012)

ITU-T Study Group 15 - Optical transport networks and access network infrastructures

This page refers to a previous study period. For its most recent version, please see here.

Study Group 15 is the home of the digital subscriber line (DSL) standards that provide the broadband Internet connections for over 600 million households around the world. It also works on optical access and backbone technologies.

A key concern for many operators is how to maximize network capacity in the last mile (between the exchange and the customer premises). SG 15 standards on DSL are one way of helping towards this goal. The latest DSL standards are ADSL 2+ and VDSL2; both give the copper cable owned by many incumbent telcos around the world an extended lease of life and bring higher bandwidth to small businesses and residential customers.

Work highlights

Less familiar, but equally important, are SG15 standards (ITU-T Recommendations) relating to passive optical networks (PONs). PONs are an effective way of implementing fibre-to-the-home/building, etc., and a crucial step towards all-optical networks. By eliminating the dependence on expensive active network elements, the use of PONs enables carriers to make significant savings.

SG 15 also plays a leading role in the development of standards for the backbone architecture, including the key standard for synchronous data transmission over fibre-optic networks, synchronous digital hierarchy (SDH).

Wave division multiplexing (WDM) technology is another technology in which ITU-T standards have played a very important role. WDM increases the data-carrying capacity of an optical fibre by allowing simultaneous operation at more than one wavelength.

Additionally, SG 15 is working on automatically switched optical networks (ASONs). ASONs provides quick and reliable service activation to service platforms such as switches and routers. ASONs give operators a way to dynamically manage network traffic to ensure a high quality of service, e.g., rerouting traffic away from points of failure.