The OCTAPUS project aims to address the continuing rise in the demand for fixed and mobile bandwidth capacity driven by video streaming services and the rapid adoption of Machine-to-Machine communications (e.g. Smart Home, Industry 4.0 IoT etc.). At the same time, emerging 5G and industrial Internet applications, classified under the Ultra-Reliable and Low Latency Communications (URLLC) category, impose stringent latency-oriented performance requirements, calling for a radical new architecture at the key aggregation infrastructure in local proximity to the subscribers: the Central Offices (COs). To support the enormous traffic volumes and retain the capability of flexible and efficient rollout of new services, the telecom industry envisions exploiting virtualization and SDN technologies to equip traditional COs with automatic service provisioning features. However, despite this architectural shift, a careful look into the CO anatomy still reveals unresolved issues that require a multi-faceted approach to truly realize the NGCOs:
• Recent state-of-the-art CO-grade switches are not future-proof and even the most advanced datacenter-grade switches cannot offer line-rate switching above 51.2Tbps. At the same time, conventional OLTs employ an electrical backplane to interconnect the respective line cards, which cannot keep up with the development of next-generation solutions due to the huge power consumption and latency incurred in the high-power SerDes and DSP interfaces.
• The OLT’s electrical backplane typically provides non-configurable, non-scalable connectivity between Uplink Switches (facing the metro network) and Interface (IF) cards (facing the access network), as the OLT chassis crucially limits the number of IF cards. Attractive features such as load balancing and bandwidth steering among multiple Uplink Switches within the electrical backplane would necessitate the use of ultra-high-speed switches beyond the current technological capabilities.
• With the first version of ITU-T’s single wavelength 50G PON standard released in September 2021, there is a clear and urgent need to equip the NGCO’s access-side IF cards with energy- and cost-efficient 50G O-band transceivers capable of supporting the challenging optical link budget.
• Despite the growing maturity of the SDN technologies, progress in consolidation of the software controllers with the underlying NGCO physical layer (and particularly the optical layer interfaces) remains an open issue with vendors providing, at best, limited proprietary controllers.
• The 5G RAN disaggregation into distinct Central Unit (CU), Distributed Unit (DU) and Remote Unit (RU) entities has introduced two major challenges: i) the need for coexistence of multiple X-haul flows with disparate traffic requirements in terms of throughput, latency, and jitter, and ii) the increased distance between CU/DU and RU exacerbates the limited delay budget of time-critical applications, particularly for fronthaul services, and necessitates that the NGCO delivers deterministic latency bound guarantees in the spirit of the Time Sensitive Networking (TSN) family of standards. Thus, the NGCO should incorporate the required TSN capabilities, demarcating from existing CO approaches which currently offer no such capabilities. For more latency-stringent applications, where even standard store-and-forward packet processing may introduce unacceptable delays, there is currently no mechanism within COs for creating “Express” paths that would bypass most active equipment and directly interconnect service endpoints with the minimum possible latency.
The OCTAPUS project aims to fill the gaps described above by targeting the following objectives:
• Design and develop an ultra-low-power, ultra-high-capacity, reconfigurable and modular Optical Circuit Switching (OCS)-based backplane for NGCOs to replace the OLT’s current power-hungry electrical backplane, while offering any-to-any connectivity and allowing for on-demand bandwidth steering and transparent capacity upgrades beyond 51.2 Tbps.
• Design and develop an energy- and cost-efficient O-band 50GHz On-Off Keying Non-Return-to-Zero transceiver component and I/O portfolio and combine it with low-power electronic driver and Transimpedance Amplifier (TIA) ICs for board-to-board and long-reach PON communication 800 Gbps (16x50 Gbps) transceiver engines, in anticipation of the emerging 50G PON solutions.
• Rearchitect the NGCO infrastructure and equip the NGCO’s Uplink switches and IF cards with TSN functionality (never included in the COs before) to concurrently support multiple different layers of latency with respect to traffic provisioning and secure low congestion and guaranteed service delivery for TSN traffic.
• Develop and deploy an overarching SDN-driven network orchestration framework to coordinate the NGCO’s control plane and provide the means of flexible network and device (re)configuration, network slicing and service multiplexing targeting low latency, unified and vendor-agnostic configurability and support for custom SDN applications.
Encompassing all above hardware/software innovations, the figure below presents the general scope and vision of OCTAPUS
