ZXA10 C600E: Industry’s First New-Generation Tbps-Level All-Optical Access Platform

In the post-pandemic era, broadband network development is gaining renewed momentum. Specifically, the development of broadband access has five characteristics:

• Dominance of video services in broadband network traffic: Video services have garnered favor among a vast user base through their flexible presentation, robust interactivity, and real-time accessibility. The widespread popularity of platforms such as Netflix, YouTube, and TikTok is further propelling the growth of video services. In addition, video is developing into fragmented and short-form content. According to reports from consulting firms, video services now account for over 50% of global broadband traffic, affirming the adage that “video is king.”
• Increased demand for symmetrical bandwidth: The emergence of applications like remote work, interactive community, online education, online gaming, and live-streamed shopping has spurred a heightened demand for symmetrical bandwidth. This marks a departure from the traditional traffic model, where downstream bandwidth far exceeded upstream bandwidth, and poses new requirements for enhancing end-to-end network bandwidth.
• Accelerated digital transformation: In the realm of home connectivity, there is a gradual shift away from aging twisted-pair and coaxial cable infrastructure towards fiber-optic solutions. While fiber to the home (FTTH) deployment is still in progress, fiber to the room (FTTR) has emerged as a new trend and a transition to an all-optical home network is becoming the prevailing direction. By the end of 2022, fiber to the anything (FTTx) users had accounted for more than 65% of fixed broadband (FBB) subscribers. In the realm of corporate campuses and various industries, the adoption of passive optical network (PON) in place of traditional Ethernet has become an industry consensus. FTTx deployment is extending from home settings to corporate campuses, empowering a multitude of industries.
• Low-cost evolution: In the post-pandemic era, there is a growing emphasis among operators on cost control. This necessitates network equipment to possess extended deployment and adaptability capabilities, including backward compatibility and forward scalability, to prolong the in-service lifespan of the devices.
• Finalized 50G PON standard: With Recommendation G.9804.3 released in 2021 and G.9804.3 Amendment 1 issued in 2023, the 50G PON standard has been finalized. 50G PON is expected to  see a commercial deployment in 2025.

With a profound understanding of the development trends in FBB, ZTE launched the new-generation Tbps-level all-optical access platform, ZXA10 C600E, at the Network X 2023 trade show. On one hand, this platform is compatible with the service cards of the massively deployed ZXA10 C600 (Fig. 1), allowing for flexible card intermixing and smooth evolution during network upgrades and service deployments. On the other hand, its bandwidth capacity meets the requirements for large-scale deployment of 50G PON. The platform enables deterministic networking and provides open capabilities to gain enhanced adaptability. Moreover, it adopts energy-efficient technologies to build a sustainable green network.

ZXA10 C600E has the following features:

• Compatibility with the service cards of ZXA10 C600: To ensure smooth network evolution and seamless platform switchover, ZXA10 C600E is forward-compatible with service cards of ZXA10 C600, including GPON, 10-Gigabit-capable symmetric passive optical network (XG (S)-PON), Any-PON, Combo PON, 50G PON Combo, point-to-point (PtP), and Ethernet uplink cards. This facilitates hybrid networking of ZXA10 C600E and ZXA10 C600, allowing for the intermixing of service cards. As a result, operators can minimize the expenses associated with network upgrades.
• Tbps-level per-slot bandwidth capability to meet the requirements for large-scale 50G PON deployment: Employing the Combo PON concept to implement the evolution from GPON to 10G PON and further to 50G PON is a cost-effective solution that requires minimal changes to the existing network. Tbps-level bandwidth meets the requirements for large-scale deployment of the 50G PON, 10G PON and GPON Combo solution. GPON, 10G PON, and 50G PON optical network units (ONUs) can be connected on demand and coexist within the same optical distribution network (ODN), without the need to modify existing optical line terminals (OLTs) and ODN. 50G PON devices are highly compatible with the in-service ONUs, minimizing the cost of network upgrades.
• Deterministic bandwidth and latency: To meet the requirements for deterministic bandwidth, low latency, and low jitter in certain industrial scenarios and campus environments, ZXA10 C600E employs hard pipes to guarantee the necessary bandwidth and low latency for services. For instance, through the use of single-frame multi-burst technology to trade bandwidth for time, the latency can be reduced by up to 75%. The hard pipe technology is employed to create hard slices for downstream PON traffic. By adopting a hard pipe scheme, the original scheme of statistical multiplexing for downstream PON traffic is optimized to ensure the performance. The dynamic bandwidth allocation (DBA) on the PON ports is based on time-slot scheduling and can achieve fixed slots, fixed bandwidth, and fixed latency (Fig. 2). This ensures that the end-to-end latency for traffic flowing through the PON system remains constant and deterministic. On the software side, the system can timestamp deterministic traffic at the entry. At the exit, in addition to the regular first in first out (FIFO) queues for QoS scheduling, a separate scheduling queue is in place for each deterministic traffic flow. According to the timestamp and fixed latency of a deterministic traffic flow recorded at the entry, priority scheduling is performed to ensure precise end-to-end latency control for packets as they traverse the PON system.

• Openness: ZXA10 C600E uses an open network architecture and supports the standard NetConf/YANG protocols, enabling it to be managed by third-party element management systems (EMSs) or software-defined networking (SDN) controllers and to be orchestrated by third-party orchestrators. It enables telemetry with performance statistics and analysis produced in seconds. With its built-in blade servers, ZXA10 C600E supports third-party applications, thereby creating an open and decoupled network architecture.
• Energy efficiency: ZXA10 C600E employs four levels of energy-saving measures—at the equipment, service card, port, and chip levels—to construct a sustainable FTTx network. These measures involve supporting multiple generations of PONs in the same device, dynamic energy reduction for service cards and fans, and shutdown or idling of service cards and ports as needed. Future port traffic can also be adjusted based on network traffic predictions at PON ports to lower energy usage. These measures collectively reduce power consumption and carbon emissions of ZXA10 C600E, contributing to the development of an eco-friendly FTTx network.

As a next-generation all-optical access platform, ZXA10 C600E boasts enhanced functionalities and superior performance compared to ZXA10 C600. Positioned to meet the future demands of optical access network deployment and technological evolution, ZXA10 C600E is poised to become the primary optical access platform for the 50G PON era.