# Is Traditional LC Obsolete? My thoughts on how VSFF/MPO-16 are driving 1.6T AI data center upgrades. > Source: > Published: 2026-09-21 07:43:49+00:00 With the computing power revolution sweeping the globe, driven by Large Language Models (LLMs) and Generative AI (AIGC), data centers are undergoing an unprecedented architectural remodeling. In AI clusters (such as the NVIDIA Blackwell platform and next-generation architectures), interconnection between GPUs imposes extremely stringent requirements on bandwidth, latency, and cabling density. In 2026, global hyperscale AI data centers are rapidly transitioning from 400G/800G to the 1.6T network era. As the industry moves towards 1.6T, how can data centers construct highly reliable fiber networks in this computing red ocean characterized by extremely limited physical space, demanding cooling requirements, and exponentially growing bandwidth? This article will deeply analyze the latest technical trends and best cabling practices in AI data center optical interconnection. *I. Three "Extreme Challenges" for the Physical Layer of AI Computing Centers* Traditional cloud data center cabling primarily serves North-South traffic. However, the "parameter synchronization" and "All-to-All" communication characteristics of AI clusters have led to an explosive growth of East-West Traffic within and between racks. This brings three major challenges to the physical layer: **Generational Leaps in Bandwidth and Data Rates** **1.** Optical transceiver speeds are doubling every two years. While 800G (e.g., 800G-DR8/FR8) has become mainstream in AI networks, 1.6T transceivers compatible with the "NVIDIA Quantum-3" or "800G-DR8 Ready" standards are witnessing large-scale deployments in Q3/Q4. This means a single port must accommodate more and faster fiber channels (such as 200G PAM4 per lane). **2. Physical Limits of Rack Space (Density)** As GPU server power consumption surges, single-rack power density is evolving from a traditional 10kW to over 100kW+ (liquid-cooled racks). Every millimeter of physical space is invaluable. Ports on high-density network switches (OSFP-XD/QSFP-DD) are extremely crowded; traditional MPO or duplex LC connectors can no longer satisfy such dense port layouts. **3. Conflict Between Airflow and Cooling** Dense cabling that is bulky or messy will severely obstruct airflow circulation inside server rooms and racks, reducing cooling efficiency and even causing GPUs to throttle due to overheating. Therefore, smaller cable diameters, more flexible routing, and airflow-friendly patch cord designs have become critical. *II. Core Physical Layer Technology Trends in 2026 AI Data Centers* To address these pain points, data center optical interconnection is undergoing revolutionary changes in the following directions: **Trend 1: VSFF (Very Small Form Factor) Connectors Replacing Traditional LC** In 400G/800G/1.6T optical module designs (such as QSFP-DD and OSFP), traditional LC Duplex connectors are too bulky to support multiple breakout branches on a single module panel. VSFF (Very Small Form Factor) connectors have become the absolute protagonist in high-density AI cabling, represented by: **Trend 2: 16-Core / 24-Core MPO-PLUS Structured Cabling Technology** To support wider parallel channels, trunk cables are evolving from 12-core to 16-core (16F) and 24-core (24F) MPO/MTP systems that better match high-speed transceiver architectures. **Trend 3: Smart and Visualized O&M (Numerical ID Breakout Patch Cords)** In an AI data center with tens of thousands of optical fibers, locating and replacing a faulty fiber can be an incredibly arduous task. In 2026's cutting-edge cabling solutions, breakout patch cords with Numerical IDs (such as 01-08 digital labels) have become the industry standard. By labeling each breakout end with clear, wear-resistant numbers, maintenance personnel can accurately locate specific channels in seconds. High-Density Sliding Fiber Patch Panels: Adopting a modular sliding drawer design with front-access maintenance, it allows engineers to quickly insert, extract, and adjust target fibers without interrupting adjacent traffic. **Trend 4: Factory Self-Testing and Closed-Loop Validation (SN/LC Loopbacks)** During network commissioning and cutover phases, transceiver and link self-tests are indispensable. *Conclusion: Building a Green "Optical Highway" to the Future of AI* The end of AI is power and computing, and the foundation of computing is optical connectivity. A high-density, low-loss, and easy-to-maintain physical layer network not only saves valuable data center space but also significantly improves the overall computing energy efficiency (PUE) of GPU clusters through excellent heat dissipation structures and high-bandwidth reliability.