Passive optical LANs (POLANs) have been gaining traction as an alternative to traditional switch-based Ethernet LANs due to benefits such as space savings, reduced installation cost and lower power consumption.
But with a large installed base of standards-compliant traditional infrastructure that supports flexibility, scalability and redundancy, there has been some unease in the industry regarding the ability of POLANs to measure up. This has limited widespread adoption of POLAN technology in the commercial space.
Let’s take a closer look at optimizing POLANs with structured cabling to overcome concerns and reduce adoption risk.
Using wavelength division multiplexing (WDM) technology, a POLAN is a point-to-multipoint architecture that originates at an optical line terminal (OLT) and uses passive optical splitters to split the signal from one strand of singlemode fiber into multiple signals.
The fiber from the splitters connects to optical network terminals (ONTs) in the work area that convert the optical signal to 1000BASE-T copper outputs. Category 6 patch cords are used to connect a variety of IP-based devices. ONTs are powered devices that can incorporate power over Ethernet (PoE).
ONTs can also be placed in an enclosure in a zone configuration to server multiple users. Larger rack-mounted ONTs residing in a telecom closet can connect to up to 90m of copper cabling out to work areas, much like a workgroup switch in a typical switched-based LAN.
Because a POLAN uses passive components between the ONT and OLT, they can provide greater energy efficiency with up to 60% less power utilization than a traditional switched-based LAN. There is also less maintenance and troubleshooting due to fewer electronics.
The small diameter of singlemode fibers and the reduced amount of cable can also provide up to 80% space savings over traditional switched-based LANs, as well as significant installation savings. Bandwidth-intensive singlemode fiber also means that ONTs can technically be located up to 12 miles (20km) from the OLTs.
All of these benefits make POLANs well suited for large multi-user venues like hotels, dormitories and hospitals that have limited space and for those looking to decrease overall energy, installation and operational costs. Environments like stadiums and historical construction that can’t support the 100m distance limitation of a traditional switched-base LAN are also viable candidates for a POLAN.
Network cabling standards for commercial buildings have long recommended a structured cabling infrastructure using connections points at patching areas to enable connecting and disconnecting network equipment and devices in telecommunications rooms. This practice facilitates MACs without disrupting the remainder of the cabling plant, while improving the ability to troubleshoot, reconfigure, and maintain proper administration at a single location.
While POLANs have been successfully deployed using direct connections, incorporating fiber patch panels to add connection points between OLTs and splitters and between splitters and ONTs can optimize POLAN deployments with the added benefits of structured cabling.
The structured cabling approach improves the flexibility of POLANs—MACs and equipment upgrades can be achieved with minimal service disruption, and it provides better support for establishing back-up or redundant connections.
TIA is currently in the process of taking a closer look at POLANs to set performance requirements and provide recommendations for designing and deploying these systems. Not only will endorsement by TIA accelerate product development, it will also help to increase adoption. One of the goals is to integrate POLANs with existing best practices for structured cabling, including the use of connection points.
Belden POLAN Solutions with high-performance, easy-to-install and scalable components can help you optimize passive optical LANs over structured cabling. To learn more, download our white paper, “How You Can Optimize Passive Optical LAN through Structured Cabling”.
Throughout his career Stephane has worked in the telecommunications industry; in R&D, product management, training and marketing. Since 2014, Stephane as Director Technology and Applications is focusing on technology roadmap and ideation, networking applications and trends, and standards engagement.