As artificial intelligence (AI), high-performance computing (HPC), and large-scale distributed training continue to evolve, data center networks face growing demands. GPU clusters are expanding, communication between servers is becoming increasingly intensive, and networks must deliver more than higher bandwidth. Power efficiency, latency, resource utilization, and connection flexibility are also becoming critical considerations. Against this backdrop, traditional electrical switching, Optical Circuit Switching (OCS), and Optical Cross-Connect (OXC) have emerged as important technologies in data center network design.

However, these technologies are not simply interchangeable alternatives. Electrical switching excels at packet forwarding, OCS establishes reconfigurable optical paths, and OXC generally focuses on optical cross-connection and path management within optical networks. Each has a distinct role, with different advantages, limitations, and deployment requirements. So, how should network architects choose the right switching architecture for the evolving needs of AI data centers?

1. Electrical Switching: The Foundation of Data Center Packet Forwarding
Traditional electrical switching remains a fundamental part of modern data center networking. Taking Ethernet switches as an example, these devices receive packets and forward them to the appropriate output ports based on packet information and forwarding tables. In a typical Leaf-Spine architecture, Leaf switches connect servers or compute nodes, while Spine switches provide high-speed connectivity between Leaf switches. This multi-tier design enables data centers to build scalable networks with high bandwidth and redundancy.

How Does Electrical Switching Work?
Electrical switches primarily process packets in the electronic domain. Depending on the device and network configuration, forwarding decisions may involve MAC addresses, IP addresses, routing information, and other packet metadata. Modern data center switches support high-speed interfaces, advanced routing and traffic-management functions, and integration with network automation and monitoring systems.

Key Advantages
Flexible packet forwarding
Electrical switches can make forwarding decisions on a packet-by-packet basis, making them suitable for diverse destinations, changing traffic patterns, and fine-grained traffic management.

A mature networking ecosystem
Ethernet, IP routing, congestion management, network telemetry, and automated operations provide a well-established foundation for deployment and maintenance.

Adaptability to diverse traffic patterns
Electrical switching is well suited to workloads involving numerous short flows, bursty traffic, and communication that requires flexible routing decisions.

Deployment Considerations
As port speeds and switching capacities increase, power consumption, cooling requirements, equipment costs, and network architecture become important design considerations.

However, the power consumption and latency of electrical switching depend on the specific equipment, switch architecture, port speeds, traffic load, and network topology. These factors should be evaluated in the context of the overall system rather than treated as universal limitations.

Typical applications: General-purpose data center networks, Ethernet switching, complex packet forwarding, AI cluster networks, and environments requiring mature network management capabilities.

2. OCS: Enabling Flexible Connectivity Through Optical Path Reconfiguration
Optical Circuit Switching (OCS) takes a different approach. Instead of processing individual packets, an OCS system establishes configurable optical paths between selected input and output ports, allowing optical signals to pass through the switching fabric. In a 3D MEMS-based OCS, for example, controlled micromirrors steer incoming optical signals toward designated output ports, establishing the required optical connections. Unlike conventional electrical switching, which processes packets within the switching system, an OCS fabric can switch optical signals directly in the optical domain without performing packet-level electronic processing inside the fabric.

Key Advantages of OCS

Reduced optical-electrical conversion requirements
OCS can avoid optical-electrical-optical (O-E-O) conversion within the optical switching fabric. This may reduce conversion-related power consumption and processing overhead compared with architectures that perform such conversions at the switching stage. The actual system-level benefit depends on the overall network design and the equipment being replaced. O-E-O conversion may still occur elsewhere in the end-to-end network.

Support for multiple data rates and signal formats
Because the optical switching fabric directs optical signals rather than interpreting packet contents, it can support different transmission rates and signal formats within the limits of its optical specifications and interface requirements. For example, 400G and 800G links may be carried through a suitable OCS system, subject to compatibility, optical performance, and link-budget requirements.

Reconfigurable optical connectivity
OCS allows optical paths to be established and reconfigured according to network requirements. In AI clusters with identifiable or predictable communication patterns, this capability provides additional flexibility in network topology design and resource allocation.

High-port-count optical switching
Matrix optical switches based on MEMS and other technologies can support configurable connections across multiple ports. High-port-count OCS systems provide an option for managing large numbers of optical paths within a switching fabric.

Limitations of OCS
OCS is not the best choice for every type of data center traffic. First, an established optical circuit generally remains configured for a period of time. Unlike electrical switches that make packet-level forwarding decisions, OCS is not designed to replace all fine-grained packet-switching functions. Second, optical reconfiguration introduces switching overhead. The benefits depend on switching time, traffic duration, control-system capabilities, and whether the reconfiguration process aligns with application requirements.

Deployment also requires careful consideration of insertion loss, optical isolation, port capacity, optical power budgets, control interfaces, link protection, and fault recovery. The primary advantage of OCS is therefore not the wholesale replacement of electrical switching. Rather, it provides an additional layer of configurable optical connectivity where the application and network architecture justify its use.

Typical applications: AI training clusters, high-performance computing, networks with sustained or predictable high-volume communication, and data center interconnect environments requiring reconfigurable optical paths.

3. OXC: Cross-Connecting and Managing Optical Network Paths
An Optical Cross-Connect (OXC) is generally a device or system that connects optical inputs to selected outputs across multiple ports or directions. OXCs are widely used in optical transport networks and data center interconnect applications. Compared with OCS, OXC emphasizes the cross-connection and system-level organization of optical paths. Actual OXC products can use different switching technologies and architectures, depending on their intended applications. Importantly, OCS and OXC are not mutually exclusive technologies. OCS describes an optical circuit-switching approach, while OXC often describes a device or system that provides optical cross-connect functionality. Some OXC systems can use OCS technology as their underlying switching mechanism.

How Does OXC Work?
An OXC receives optical signals from multiple ports or network directions and connects them to designated output ports or transmission paths according to configured routing requirements. Depending on the system, OXC functionality may operate at the fiber level, wavelength level, or another optical cross-connect granularity. Some systems may also integrate amplification, monitoring, protection, or other transport functions, although these capabilities are not present in every OXC. For example, in a multi-site optical transport network, an OXC can help redirect optical connections across different transmission paths and network nodes.

Key Advantages
Organizing complex optical connections
In networks with multiple nodes, transmission directions, and optical paths, OXC systems help operators manage and reconfigure cross-connections.

Supporting system-level optical path management
OXC can serve as an important part of optical transport infrastructure where numerous connections must be coordinated and maintained.

Integration with optical transport technologies
Depending on the architecture, OXC systems can work alongside wavelength-division multiplexing (WDM), optical amplifiers, optical transport equipment, and network management systems.

Deployment Considerations
OXC capabilities and complexity depend heavily on the specific product. Network architects should evaluate switching granularity, supported optical interfaces, wavelength-handling capabilities, port capacity, control and management interfaces, and the availability of required monitoring and protection functions.

Other considerations include fiber-resource planning, optical link budgets, equipment compatibility, network protection, and total lifecycle costs. For high-speed Ethernet connectivity within an AI cluster, an OXC is not necessarily the direct solution to every networking challenge. However, it can play an important role in networks that require multi-port optical cross-connection, multiple transmission directions, or more complex optical path management.

Typical applications: Optical transport networks, data center interconnect (DCI), multi-node optical networks, systems requiring flexible optical cross-connections, and environments integrating multiple optical transport technologies.

4. OCS vs. OXC vs. Electrical Switching: Key Differences
The most important distinction between these technologies lies in how they handle traffic and the functions they perform within the network.

OCS and OXC overlap conceptually, so this comparison reflects their common functional roles rather than an absolute separation between product categories.

5. How Should AI Data Centers Choose?
For AI data centers, the key question is not simply which switching technology to select. It is where each technology should be deployed and how different technologies can work together.

Scenario 1: General-Purpose Data Centers and Diverse Packet Traffic
When a network must handle packets with many different destinations and relies on mature routing, congestion management, and operational automation, electrical switching generally remains the foundation. It can handle flexible packet forwarding without requiring the entire network to be redesigned around optical circuit switching.

Scenario 2: Large-Scale AI Training Clusters
In clusters containing large numbers of GPUs or accelerators, some communication patterns may be concentrated, repetitive, or relatively predictable. If the network can identify traffic suitable for optical circuit connections, and the reconfiguration overhead is compatible with the duration and characteristics of that traffic, OCS can complement electrical switching by optimizing connectivity between selected nodes or network partitions. However, the benefits must be evaluated against actual traffic matrices, topology, optical path scheduling, and fault-recovery requirements. Not every AI workload will benefit equally from OCS.

Scenario 3: Interconnecting Data Centers or Network Sites
When a network spans multiple data centers, transmission directions, or complex fiber connections, OXC and related optical transport equipment can help manage and reconfigure optical paths. If the primary requirement is to establish high-capacity, reconfigurable end-to-end optical connections, OCS may also be a suitable option. The final choice depends on switching granularity, transmission distance, wavelength management, and system integration requirements.

Scenario 4: Gradually Upgrading an Existing Network
For data centers with substantial existing electrical switching infrastructure, a hybrid architecture may be more practical than a complete replacement. Network operators can begin by analyzing existing traffic patterns, identifying high-capacity and relatively sustained communication demands, and evaluating whether OCS should be introduced at selected network layers. This approach can reduce the risks associated with large-scale architectural changes while allowing performance and operational benefits to be validated through pilot deployments.

6. What Should Network Architects Evaluate Before Deploying OCS?
Moving from technical validation to production deployment requires a comprehensive evaluation of device performance, network control, and manufacturing readiness.

1. Traffic patterns and optical circuit utilization
Analyze traffic matrices, flow duration, peak bandwidth, and communication patterns. Reconfigurable optical connectivity creates value when circuit configurations align with actual workload requirements.

2. Port capacity and network topology
Determine whether the available port count supports the required connections. Consider port utilization, expansion options, redundancy, and future capacity requirements.

3. Optical performance and link budgets
Insertion loss, optical isolation, connector losses, transmission distance, and receiver power requirements all influence system design. Device specifications must be evaluated against the complete optical link budget.

4. Switching time and control integration
Verify switching time, configuration methods, management interfaces, and compatibility with existing network control systems. Automated, workload-aware optical reconfiguration may also require scheduling software, control policies, and fault-handling mechanisms.

5. Reliability and maintainability
Evaluate long-term operating stability, switching endurance, fault detection, recovery strategies, and maintenance procedures. Qualification requirements should reflect the intended application.

6. Manufacturing capability and supply assurance
As deployments expand beyond pilot projects, equipment must be supported by consistent production quality, repeatable testing, and reliable delivery. Manufacturing consistency and long-term supply capability are important parts of technology selection.

By evaluating these factors within the context of the complete network architecture, operators can determine whether OCS is suitable for a specific application and how it should work alongside electrical switching and other optical networking equipment.

7. GLSUN: Optical Switching Solutions for AI Data Centers
As AI clusters drive growing demand for high-speed interconnects and flexible network architectures, optical switching is becoming an important area of data center infrastructure development.

GLSUN continues to develop optical switching technologies, offering 3D MEMS-based OCS equipment and matrix optical switching solutions for applications requiring configurable optical connectivity.

For AI data centers and HPC environments, GLSUN's OCS products provide hardware options for evaluating and building reconfigurable optical network architectures. Specific deployment solutions should be designed around port capacity, optical performance, control interfaces, link budgets, and customer network topology requirements. Beyond optical switching, GLSUN's broader business spans optical chips, optical components, modules, and system-level equipment, reflecting the group's presence across multiple areas of photonics technology and manufacturing. For individual projects, network architects can evaluate how GLSUN's OCS products may work alongside existing electrical switches, optical transport equipment, and network management systems to support future network expansion and architectural evolution.

Conclusion: The Future Lies in Architectural Collaboration
Electrical switching, OCS, and OXC are not simply competing alternatives. Electrical switching remains the foundation for flexible packet forwarding in modern data centers. OCS introduces reconfigurable optical connectivity that can help optimize optical resources in suitable applications. OXC focuses on organizing and managing cross-connections within optical networks. As AI data centers evolve, network design will increasingly consider not only bandwidth, but also connectivity, resource scheduling, energy efficiency, and system scalability. For network architects and data center operators, the most effective strategy is not to adopt a single technology indiscriminately, but to build a hybrid architecture aligned with actual traffic patterns, deployment objectives, and operational capabilities. By combining electrical and optical switching technologies where appropriate, data centers can gain greater flexibility in network design. GLSUN will continue advancing optical switching technology and photonics manufacturing to help customers explore flexible optical networking solutions for the AI era.