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BSS/OSS Academy
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Section 11.8

ITU-T

The standardisation sector of the UN's ITU, whose Recommendations define numbering, optical access and the TMN management model that OSS layering descends from.

ITU-T is the standardisation arm of the International Telecommunication Union, a United Nations agency whose members are governments as well as companies. It is the oldest body in this section by a century and the one an architect meets least directly — its work is the substrate everything else assumes. Its outputs are Recommendations, grouped into lettered series, and adopted into national regulation and operator practice around the world. Since 2007 they have been free to download.

Three series matter for BSS/OSS. E-series defines numbering and routing: E.164 is why a phone number has a country code and at most fifteen digits, which is why number portability and interconnect look the way they do. G-series defines transmission and optical access — GPON is G.984, XGS-PON is G.9807 — the fixed-access technologies module 6 orchestrates. M-series defined network management: M.3010's Telecommunications Management Network, with its element / network / service / business management layers, and the FCAPS functions M.3400 enumerates, are the direct ancestor of the EMS / NMS / OSS layering this Academy still uses. ITU-R, the radio arm, sets the IMT-2020 requirements that 3GPP's 5G specifications were written to meet.

ITU-TTelecommunications recommendation

ITU-T Recommendations

What is it?

The standards of ITU-T, the standardisation sector of the ITU (a United Nations agency), published as lettered series of Recommendations: E for numbering and routing (E.164 is why a phone number looks the way it does), G for transmission and optical access (GPON is G.984), M for management (M.3010 defined the Telecommunications Management Network that OSS layering descends from), Y for next-generation and IMT-2020 networks, X for security.

What problem does it solve?

Makes networks in different countries and from different eras interconnect, by giving governments and operators one set of internationally agreed technical recommendations.

What does it cover?

  • •Numbering, addressing and interconnection (E-series)
  • •Transport, optical access and synchronisation (G-series)
  • •Network management principles and the TMN model (M-series)
  • •Architectures for future networks and security frameworks (Y- and X-series)

What does it NOT cover?

  • •Not an implementation architecture for BSS/OSS.
  • •Does not define mobile radio or core — ITU-R allocates spectrum and sets the IMT requirements; 3GPP writes the specifications.
  • •Recommendations are voluntary; national regulators decide what to mandate.

Where does it fit?

NetworkInfrastructureNetworkOperationsSecurity

When would an architect use this?

  • •Numbering, number portability and interconnect design
  • •Fixed access and transport technology choices
  • •Understanding where the FCAPS / TMN layering behind OSS came from

Where you'll meet it in the Academy

Official source: itu.int/ITU-T. Recommendations are free to download.