Optical access evolutions towards SDN and disaggregated hardware: an operator perspective [Invited]

Abstract

In this paper, we review recent advances of the optical access network in the path toward Cloud-computing-related technologies, software defined networking, and network function virtualization. We present the new network management architectures proposed by standardization bodies such as the Broadband Forum and non-profit organizations such as the Open Networking Foundation and propose to use today’s Orange-France Operation Support System as a baseline to discuss different evolution paths. We also provide a review of recent advances in the optical line terminal (OLT) hardware evolution, from white-box OLTs to general purpose hardware, and identify the remaining related challenges, such as energy consumption and interoperability. We also show how Cloud-computing technologies in optical access networks could remove the frontier between network segments (home local area network, optical transport network, and mobile network) by deeply improving the synergy among them.

Energy Conservation in Passive Optical Networks: A Tutorial and Survey

“…In academic research efforts, various deployment scenarios of edge-computing facilities co-located with PON (as a separate entity) have been considered; for example, at CO (e.g., [108], [111]), RN (e.g., [111]- [113]), and customer on-premises (e.g., [114], [115]). Recently, there is also built-in deployment of edge computing in PON OLT/ONU has been considered in current research (e.g., [116], [117]), i.e., embodied computing and storage module in OLT and ONU. In 2023, the European Telecommunications Standards Institute (ETSI) has released documents for industrial PON deployment, where built-in network edge computing capability in OLT and ONU has been recommended (e.g., in [110]) to gain several benefits, including real-time decision making closer to data sources, reduction of uplink data volume, and protocol conversion.…”

“…In a PON, a white box OLT, where hardware is decoupled from the software, comes with open interfaces for all control and management related functions making it SDN integrable. It has been endorsed by ONF's SDN-Enabled Broadband Access (SEBA) project for further development [117]. White box OLTs are being embraced for commercial deployment.…”

“…Besides white box OLTs, the pluggable OLT (known as microplug OLT) is regarded as an important milestone in the evolution of OLT solutions. It comprises of transceivers integrated with real-time MAC and Transmission Convergence (TC) layer functions of OLT and is pluggable into any switch or router [117].…”

“…Flexible Access System Architecture (FASA) project in 2016 was introduced by Japanese operator NTT [117]. The OLT modularization approach NTT introduced in FASA is comprised of three parts: software modules, general-purpose hardware and dedicated optical module with physical chips [117], [189]. The dedicated optical module (not virtualized) equipped with optical transceivers.…”

“…The dedicated optical module (not virtualized) equipped with optical transceivers. The software modules are the OLT functions that run as VNFs in a remote location, whereas the time-critical OLT functions run locally in a general-purpose hardware [117]. Motivated by the benefits of modularization and softwarization such as faster policy update and improved energy efficiency and reliability, besides the non-time-critical functions, FASA aims to modularize the time-critical functions (e.g., DBA, ONU sleep control and PON protection) [190].…”