NG-PON2
Next-Generation Passive Optical Network 2 | |
Status | In force |
---|---|
Year started | 2015 |
Latest version | 1.0 March 2020 |
Organization | ITU-T |
Committee | ITU-T Study Group 15 |
Base standards | G.983,G.984 |
Related standards | Higher Speed PON |
Domain | Telecommunication |
License | Freely available |
Website | https:// itu.int/rec/T-REC-G.989 |
NG-PON2(also known asTWDM-PON),Next-Generation Passive Optical Network 2is a 2015 telecommunications network standard for apassive optical network(PON). The standard was developed byITUand details an architecture capable of total network throughput of 40 Gbit/s, corresponding to up to 10 Gbit/s symmetric upstream/downstream speeds available at each subscriber.[1][2]
A passive optical network is a last mile,fibre-to-the-xtelecommunications network that broadcasts data through fibre optic cables. PONs are managed by passive optics such as unpowered splitters and filters, offering high reliability and low cost compared to active networks. The PON data stream is generally converted to a more traditional service such as Ethernet and Wi-Fi at the subscriber's location.
NG-PON2 is compatible with existing PON fibre by replacing optical line terminal (OLT) at the central office, and the optical network unit (ONU) near each end-user.
Unique to this standard is the use of both active filters and tunable lasers in the ONU.
From 2019 until 2021 a series of new Recommendations under the headerHigher Speed PON(G.9804 series) was released intended as successors to NG-PON2.
Technical details
[edit]![](https://upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Optical_Network_Spectrum_including_NG-PON2_wavelengths.png/450px-Optical_Network_Spectrum_including_NG-PON2_wavelengths.png)
![](https://upload.wikimedia.org/wikipedia/commons/thumb/7/70/NG-PON2_distribution_network.png/225px-NG-PON2_distribution_network.png)
Wavelength allocations include 1524 nm to 1544 nm in the upstream direction and 1596 nm to 1602 nm in the downstream direction.
The architecture calls for time- and wavelength-division multiple xing (TWDM) in the upstream and downstream directions.Wavelength-division multiple xingis provided in the downstream direction by combining light from four fixed wavelengthOLTlasers with a wavelength mux. The light is then filtered at each ONU with an actively tunable filter that passes only the desired downstream wavelength to its receiver. In the upstream direction, tunable lasers at each ONU are dynamically assigned to a wavelength. Fibres from all ONUs are combined with a passive mux/splitter.Time-division multiple xingis provided in the upstream direction through the use of burst lasers at each ONU.
Each upstream/downstream wavelength is capable of providing up to 10 Gbit/s symmetric bandwidth to each subscriber if the channel is not time-division multiplexed between several ONUs. With wavelength-division multiple xing on four available wavelengths, NG-PON2 can provide up to 40 Gbit/s throughput to the entire optical network.
Deployments for several downstream/upstream subscriber rates are described within the standard including 10/10 Gbit/s at each subscriber, 10/2.5 Gbit/s, and 2.5/2.5 Gbit/s. Additionally, some wavelengths are reserved for potential use in Point-to-Point applications.
NG-PON2 was designed to include backwards-compatibility, or coexistence, with previous architectures to ease deployment into existingoptical distribution networks.Wavelengths were specifically chosen to avoid interference withGPON,10G-PON,RF Video,andOTDRmeasurements. The standard provides spectral flexibility to occupy reserved wavelengths in deployments devoid of legacy architectures. Additionally, a mux/demux used to combine and separate the NG-PON2 wavelength channels at the OLT can be designed with a coexistence element to isolate legacy wavelengths.
Standards
[edit]The ITU-T G.989 standard is divided into these subsections:
See also
[edit]References
[edit]- ^ITU (2018-12-22)."ITU brings new clarity to 5G transport".ITU News.Archivedfrom the original on 2021-04-05.Retrieved2021-04-05.
- ^"G.989: 40-Gigabit-capable passive optical networks (NG-PON2): Definitions, abbreviations and acronyms".itu.int.Archivedfrom the original on 2021-06-15.Retrieved2021-06-15.