Broadband Forum has published standards toward the modularization of the Dynamic Bandwidth Assignment (DBA) function that enables PONs and other point-to-multipoint broadband infrastructures to enable multiple devices to share capacity. The standards, which define an API that enables the DBA software module to be replaced as service requirements demand, were developed with the assistance of NTT and Chunghwa Telecom, which jointly proposed use cases and developed the API specifications as international standards within Broadband Forum.
The flexibility the new standards promote should come in handy as operators use next-generation PON architectures to support multiple service types, including 5G fronthaul, the organization and the service providers involved expect. "These technical advances will enable carriers to use a common access system for a diverse range of services including the accommodation of base stations for 5G mobile systems, which place strict requirements on acceptable latency thresholds," said Jun Terada, general manager at NTT Access Network Service System Laboratories. "Although DBA, which requires high-speed processing in the region of sub-milliseconds, was thought difficult to modularize due to its time-critical nature, it is a crucial function that significantly impacts QoS in optical access systems. We believe that the widespread use of the API as an international standard will lead to the drastic expansion of the application area of optical access systems."
The new standards, part of Broadband Forum's PON Abstraction Interface for Time Critical Applications (TCAs) project launched by NTT in 2017, are found in two Technical Reports, TR-402 and TR-403. TR-402 offers an overview of the modularization, including a use case regarding accommodation of base stations for 5G mobile over an optical access network, and specifies the functional requirements of the API. TR-403 specifies details of the API, including format and performance requirements.
"The work completed by NTT and Chunghwa Telecom is essential to meet changing user demands, and we are proud to have had such an important project undertaken within Broadband Forum," said Robin Mersh, Broadband Forum CEO. "The work fits perfectly with our other initiatives around next-generation access and will enable operators to cost-effectively upgrade their optical access networks as they prepare for the 5G era."
Meanwhile, NTT plans to modularize the remaining access functions in cooperation with carriers, system vendors, standards developing organizations, and open source software organizations.
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