Fiber vs. Copper to the Edge: ファイバーがスマートで持続可能な建物の選択肢として成長している理由

2021 年 12 月 8 日 / 一般、標準および認証、産業用ネットワーク

For years, we’ve heard about FTTX making its way into the horizontal LAN — fiber to the desktop, fiber to the office, fiber to the enclosure, fiber to the zone, etc. Often referred to as “fiber to the edge” or FTTE, most of these deployments have traditionally been for high-security government environments or specialty applications or devices. Now, as bandwidth requirements continue to increase and the commercial real estate industry is trending towards smarter and more sustainable buildings, the question of using fiber vs. copper is more relevant. Fiber is gaining attention as a means to connect end devices in the LAN, either directly or via conversion equipment, like media converters or optical network terminals (ONTs), in point-to-point or point-to-multipoint passive optical networks.

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But what are the real advantages of fiber vs. copper to the edge? And what are the key considerations for in-building fiber networks?

Fiber vs. Copper Speed: How Fiber is More Sustainable

Whether for connecting individual devices directly via fiber or making the connections through conversion equipment, proponents of fiber in the horizontal LAN tout sustainability as a key benefit. Fiber can deliver the typical speeds of 100 Mb/s, 1000 Mb/s, and 10 Gb/s found in the LAN to much greater distances than copper cabling, which is limited to 100 meters per industry standards. Singlemode fiber can support 10 Gb/s up to 40 kilometers, and multimode fiber can support 10 Gb/s up to about 550 meters. Since there is no longer a need to ensure a telecom room (TR) within 100 meters of every end device, fiber can significantly reduce or even eliminate TR space, in some cases. And as fiber-to-the-edge proponents are quick to point out, that also means far less power consumption with less active equipment and associated cooling. Fiber also takes up much less space in pathways due to its smaller diameter and weight—anywhere from a third to a tenth that of copper. The overall reduction of material throughout the building is considered more environmentally friendly.

Fiber’s bandwidth capabilities also give it the potential to support more generations of bandwidth speeds compared to copper. Over the past few decades, we’ve seen copper cabling go from supporting 10 Mb/s with Category 3, to 100 Mb/s with Category 5e, 1000 Mb/s with Category 6, and now pretty much tapping out at 10 Gb/s with Category 6A. While fiber-to-the-edge deployments today are primarily supporting only up to 10 Gb/s, the potential is there for much higher speeds on the same infrastructure—duplex singlemode fiber can support up to 400 Gb/s, and duplex multimode fiber can support up to 100 Gb/s. While it’s unlikely that edge devices in the LAN will ever require these types of backbone speeds, a future application could conceivably require greater than 10 Gb/s to an end device in the LAN. In a fiber vs. copper cable debate, if high speed is important, fiber has the edge.

How Are Devices Powered in a Fiber LAN?

When it comes to deploying fiber to end devices in the LAN, one consideration is that few devices today actually feature a fiber input/output. This may limit the selection for surveillance cameras, wireless access points, access control, digital displays, and other connected edge devices that typically feature RJ-45 ports for connecting to copper cabling. Most of these copper-based devices today are also powered over copper cabling via Power over Ethernet (PoE) technology, which eliminates the need for an AC power run to every device. While fiber can’t connect to a copper RJ-45 port or carry power, there are options.

If a device doesn’t feature a fiber input/output, conversion equipment like a media converter or ONT can change the signal from optical to electrical and connect to the device with a short copper patch cord. Most conversion equipment today can also deliver PoE to devices, but that means you still need to get power to that conversion equipment. While local AC power is an option, that pretty much defeats the purpose of using PoE, which is why hybrid copper-fiber cable is the preferred method of getting power to the edge. You will, however, need a power source and careful planning to ensure enough power based on how much the device draws and the distance from that source. Once powered up, you can easily test port speed and PoE level for any port on a media converter or ONT using a cable + network tester like Fluke Networks’ LinkIQ™.

How Do I Test Fiber in the LAN?

Just like with fiber links in backbone and data center environments, it’s important to clean and inspect horizontal fiber links prior to termination at either end. A fiber optic scope like Fluke Networks’ FI-3000 / FI2-7300 FiberInspector™ Ultra Camera is great for inspecting virtually any fiber connector, including APC singlemode connectors used in passive optical LANs. This compact, ergonomic, and lightweight inspection solution offers autofocus and autotest, as well as the ability to share and report on fiber inspection data.

When it comes to performance testing, most fiber-to-the-edge deployments require Tier 1 insertion loss testing using an optical loss test set like Fluke Networks’ CertiFiber Pro, with minimum and maximum values dependent on the application and vendor equipment. For example, insertion loss for a passive optical link can range from 13 dB for minimum to 28 dB for a maximum, including all components in the link (i.e., splitters). If your fiber-to-the-edge deployments use wave division multiplexing (WDM), where three different wavelengths are used to carry downstream data, upstream data, and video signals, testing must be done at both the lowest and the highest wavelengths. If you’re no stranger to fiber, you also likely know that basic troubleshooting involves using an optical fault finder, like Fluke Networks’ VisiFault™, to locate loss events and breaks. For more advanced troubleshooting, an OTDR like CertiFiber Pro locates fiber breaks, bends, splices, and connectors, and measures the loss from each.

As developers seek to implement more smart building technologies while also striving to meet sustainability goals, we may see an uptick on fiber-to-the-edge deployments in the LAN. With the right combination of network tools, you’ll be able to easily inspect, test, and troubleshoot these deployments—from the end-to-end fiber links to any copper links that connect and power end devices from conversion equipment.