PON abstraction interface for time-critical applications

Functional model for PON abstraction interface

For agile service adaptation in the next-generation optical access system, a new system architecture, based on SDN/NFV technologies, is required by operators. The most promising approach is to disaggregate PON functions into functional modules with open interfaces. The BBF's all-new PON Abstraction Interface for Time-Critical Applications project develops the architecture further by specifying a PON abstraction interface for time-critical processing functions, such as Dynamic Bandwidth Assignment (DBA).

Algorithm disaggregation and interface

To make time-critical functions flexible, an appropriate software API to modify or to extend functions is required. This is achieved by disaggregating algorithms. In addition, the interface between algorithm part and common engine should be specified as common API.


Phase 1: the first of two phases defines the functional modules and interfaces so as to disaggregate a PON function (e.g. DBA) that needs time-critical processing. Some key elements being:
  • Algorithm disaggregation and interface
  • Eleven use cases for DBA for service differentiation, ONT sleep, Protection and Dynamic Wavelength Assignment (DWA)
  • Functional requirements of the APIs for time-critical applications covering low-latency DBA, ONT sleep, protection and DWA

Phase 2: Defines the detail specifications of the interfaces as commonly usable among vendors and operators.

Market Impact

There are two aspects of issues being addressed from the operator’s point of view. Firstly, the operators need to provide sustainable broadband services for residential users on widely deployed fiber access networks. To keep the services cost-effectively, operators need to update the PON functions, which include a function that needs time-critical processing, by using software update. This enables operators NOT to rebuild an OLT from the preliminary stage of development (e.g. re-make of PON chip), which requires a large amount of investment.

The second aspect is that the operators wish to provide a large variety of services on access network, such as broadband service for business users and mobile fronthaul for 5G. This should be a new business opportunity not only for operators but also for vendors, since a disaggregated OLT based on the proposal can be applicable to 5G mobile fronthaul by replacing a low-latency Dynamic Bandwidth Assignment software.

Recent related public resources
from the BBF's Fiber Access Network Work Area

  •  Architecture and Technical Requirements for Passive Optical Network (PON) Based Mobile Backhaul Networks (TR-331) approved March 2018, published April 2018

Members resources

  • Functional model for PON abstraction interface
    defines the functional modules and interfaces so as to disaggregate a PON function that needs time-critical processing (WT 402)
  • Detailed specifications of the PON abstraction interfaces for time-critical applications (WT 403)


Time-critical application

The time-critical application is a function in optical access system (e.g. PON), which requires high-speed processing, such as DBA, DWA, ONT sleep, and Protection.

PON abstraction interface

The PON abstraction interface is an API that provides flexibility of time-critical application. The time-critical application having algorithm dependent function can be disaggregated to the common behavior part as engine, and the differentiation part as algorithm. The interface between two parts are called the PON abstraction interface, and specified as an API. By using APIs, differentiation/flexibility of time-critical applications can be achieved by updating/replacing algorithm part, which is a software component.