From LAN to POL: Transitioning to a More Efficient All-Optical Network

In today's digital age, streets, cities, and nations are interconnected, enabling efficient and convenient communication. However, as more devices connect to the network, the demand for higher bandwidth and speed increases. Traditional Local Area Networks (LANs) are now facing challenges such as limited cabling space, complex management, and restricted transmission distances. To address these issues, Passive Optical LAN (POL) has emerged as a fiber-based solution.

What is Passive Optical LAN?

A Passive Optical LAN (POL) network is a system built on Passive Optical Network (PON) technology as one of the applications of PON networks, POL systems consist mainly of three components: Optical Line Terminal (OLT), Optical Distribution Network (ODN), and Optical Network Unit (ONU).

Unlike traditional LAN networks that rely on electrical signal transmission, POL networks use passive optical transmission to achieve a true "all-optical" network. This not only improves transmission efficiency but also utilizes a point-to-multipoint (P2MP) architecture, contrasting sharply with the point-to-point (P2P) architecture of traditional LAN networks.

From LAN to POL: the Difference of Network Architecture

To enable efficient optical transmission, POL networks incorporate a range of passive devices that replace the active switches used in LAN networks.

• In POL networks, the OLT handles network management, data forwarding, switching, and processing. It also coordinates the multiplexing of ONUs to share upstream transmission. The OLT is typically installed on the service provider's side and can remotely monitor and manage connected ONUs through protocols like OMCI, SNMP, and TR-069. During deployment, additional cards or equipment density can be added to expand network capacity.

• Access switches in the network are replaced by various ONU devices. ONUs typically include Ethernet interfaces, voice interfaces, and cable TV interfaces to handle different types of service connections. Depending on the application, ONUs can be classified into SFU, HGU, SBU MDU and MTU. For more details: SFU, HGU, SBU, MDU, MTU: A Quick Guide to ONU/ONT Differences.

• In traditional LAN networks, the aggregation layer function is performed by the PLC. The PLC aggregates optical signals and, along with optical cables, fiber connectors, and other accessories, completes the transmission of optical signals. This forms a complete data aggregation and transmission pathway, connecting the OLT with the ONU.

Key Benefits of POL Networks

This architectural update provides the POL system with several significant advantages:

Enhanced Space and Energy Efficiency

In traditional LAN networks, in addition to core switches, a range of supplementary facilities is required to ensure stable network operation, including aggregation of weak current rooms, cooling systems, and fire safety equipment. In contrast, POL networks use passive optical splitters to distribute optical signals without the need for additional power support. Moreover, the passive nature of these devices effectively reduces potential fire risks.

Seamless Bandwidth Upgrades

POL networks support smooth bandwidth upgrades. It is made possible by the high bandwidth capacity of the optical fibers in the ODN. During an upgrade, only the OLT and ONU devices need to be replaced with those supporting higher bandwidth, without modifying the optical fiber lines or cabling structure. This avoids the cumbersome process of rewiring and replacing numerous devices associated with traditional copper cabling networks, significantly reducing construction and maintenance costs.

Superior Multi-Service Integration

Additionally, POL networks greatly reduce network deployment and operational costs through multi-service integration. In traditional LAN networks, each copper cable typically supports only a single service. POL networks, however, use optical fiber technology to consolidate data, POTS, and CATV services onto a single fiber. This multi-service capability lowers overall costs and simplifies network maintenance and operation.

Streamlined Configuration and Management

In terms of management, POL networks exhibit unique advantages. ONUs can be pre-configured according to deployment plans, and the OLT can automatically discover and add ONUs, completing device deployment and remote software configuration through network protocols like OMCI and TR-069. Additionally, users can perform basic ONU configurations via a web interface. Compared to the on-site configuration required for switches, POL significantly enhances both deployment and management efficiency.

These advantages make POL networks an ideal alternative to traditional LAN networks, meeting current complex network deployment needs while laying a solid foundation for future development.

Boundless Potential of POL Networks

POL networks extend fiber access to the "last mile," aligning with current demands for network deployment, maintenance, and management. In the future, POL networks will play a key role in intelligent buildings, data centers, and large campuses, providing flexible, reliable, and scalable network solutions. As a global solution provider, FS continues to advance with network development, offering high-speed, secure, and flexible network deployment solutions to deliver satisfactory communication services to users.