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Draft SEBA Reference Design v2.0 Adds BNG Disaggregation, Scaling and New Services for Broadband Access Networks

Dec 16, 2020
SEBA Reference Design Team
SEBA Reference Design Team About the author

The draft SEBA Reference Design v2.0 specification was released today exclusively to ONF Members. This Reference Design (RD) was authored and is backed by multiple tier 1 operators, including AT&T, Deutsche Telekom, NTT and Türk Telekom, with contributions from ONF supply chain partner members Ciena, Netsia and Radisys. As a draft release, ONF members have 60 days to review the specification and send feedback to the SEBA Reference Design Team (RDT). The target public release date for the final SEBA RD v2.0 specification is March 2021.

SEBA (SDN-Enabled Broadband Access) is a lightweight platform for development of solutions for carrier broadband access. The purpose is to define a common infrastructure that supports a multitude of virtualized access technologies at the edge of the network. SEBA is optimized such that traffic can run ‘fastpath’ straight through to the backbone without requiring VNF processing on a server. The scope covers both wireline and fixed wireless access technologies and related Service Edge capabilities including, but not limited to, PON, XGS-PON, NG-PON2, EPON, future PON technologies, GFast, Ethernet, fixed wireless, DOCSIS and xDSL The scope is intended to simplify the adaptation of new technologies, new silicon supporting these technologies and new devices that incorporate these technologies and silicon into deployable elements.

The SEBA RD v2.0 describes the SEBA exemplar platform, specifying a common architecture to meet the network and feature needs of multiple operators. It provides a high-level architecture with well-defined APIs, giving guidance on technology choices to implement software-defined, disaggregated broadband access solutions leveraging open hardware and modular software (preferably open source) components. The SEBA RD v2.0 builds on the SEBA RD v1.0 (released to the public in March 2019), adding new features and functional enhancements. 

The major features added in the SEBA RD v2.0 include:

  • Broadband Network Gateway (BNG)
  • Per-OLT VOLTHA Stack Model for Scaling
  • Detailed NBI APIs for POD, OLT, ONT, Service Management
  • Device Management (DM)

The SEBA RD v1.0 described the general functionality of a Broadband Network Gateway (BNG) and introduced the functional disaggregation of the BNG into a service edge (BNG-SE) and a routing component. The new SEBA RD v2.0 improves BNG functionality further by defining three main interfaces between the control and user planes of the subscriber-facing function of BNG - the BNG Service Edge (BNG-SE). Moreover, three options are introduced to implement BNG Control and User Plane Separation (CUPS) in the SEBA reference platform.

The SEBA RD v2.0 adds support for horizontal scaling of VOLTHA stacks, each stack consisting of Read/Write Core, OpenFlow Agent, OLT Adapter, and ONU Adapter modules.  Each instance of the stack supports the deployment of a single OLT, and as new OLTs are required, additional VOLTHA stacks are instantiated per OLT.

The SEBA RD v2.0 also offers an enhanced Northbound API (NBI), adding new services for POD, OLT, ONT, and Service Management. The SEBA RD v2.0 defines more than 40 NBI API calls, with input/output parameters, on this standardized SEBA NBI.

Finally, the SEBA RD v2.0 introduces the Device Management (DM) functionality supported by a lightweight DM interface openly defined by the ONF community, with primary API method requirements. The SEBA high level architecture is also updated to include the new DM interface as well as the DM functionality.

Draft Review Process

As a draft Reference Design, this specification is available exclusively to ONF members who have 60 days to review and provide feedback before the final version of the RD is published.  Once published as final, the RD will be made publicly available.

For more information about SEBA, the public can download the SEBA RD v1.0 and ONF members can view this new SEBA RD v2.0 draft.  

ABOUT THE AUTHOR SEBA Reference Design Team
SEBA Reference Design Team