WIRELESS INFRASTRUCTURE

  • 12/16/2015
    8:00 AM
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What Could LiFi Mean For Enterprise WiFi?

There's a lot of hype these days about LiFi. While the light-based technology is promising, it won't replace WiFi in the enterprise anytime soon.

There's been a lot of talk recently about LiFi, the cool-sounding technology that uses light as a transmission medium, the same way that WiFi uses RF. It’s still way too early in the LiFi development cycle to predict what it will really mean to enterprise networks. At the same time, pundits are using phrases like “alternative to WiFi” liberally, so it’s worth doing a reality check on what role LiFi could play in real business network environments.

For those who haven’t read about LiFi yet, let’s do a brief overview. The technology has been around, at least in lab trials, since 2011. It has shown in controlled environments that light can carry data at rates up to 224 Gbps between the light source and a simple USB-connected detector on the client device. Outside of the lab, rates between a few Mbps and one gig have been achieved.

LiFi is part of the family of Visual Light Communications (VLC) with roots in 802.15.x standards, but doesn't seem to map exactly to any existing IEEE standard. Limited office-environment trials on prototype gear are under way, and the promise of using light instead of RF is exciting because there is an order of magnitude more spectrum available than the few hundred MHz dedicated to WiFi.

The buzz is certainly warranted, as LiFi does have a lot of promise. But as happens with so many technologies, the hype is well ahead of any demonstrated real enterprise applicability. As a network administrator, here are my thoughts on LiFi.

The media is awash in claims like “LiFi lets you download 18 movies every second!” Sounds great, but it’s a goofy metric based on that 224 Gbps lab exercise. Even if that data rate were sustainable outside of the lab, we’d have to consider the uplink capacities and backplanes available on edge switches that would connect to LiFi access points, not to mention the ISP pipes required to pull that off.

There’s also the fact that light doesn’t penetrate walls, and some large rooms would need multiple LiFi lights to keep the intensity at a level that delivers these massive data rates. So, our switch port counts also just increased by a significant multiplier, as did the UPS and electrical requirements upstream in the closets.

The obvious questions about what happens when the lights go out, or in full sunlight when detectors are “whited out” can’t be ignored, and will eventually be answered. It seems fairly obvious that LiFi won’t replace WiFi anytime soon, but could augment it. This poses interesting dilemmas: How would a client device roam from LiFi to WiFi? Would LiFi eventually support strong encryption and authentication protocols? What would an NMS look like that manages WiFi and LiFi as a dual-technology system? How hard would it be for a hacker to pop in his own LiFi eavesdropping device and bridge it to rogue WiFi for longer range?

Maybe LiFi will be relegated to the Internet of Things (IoT), or at least the Internet of Things That Don’t Need To Function In The Dark, and operated in parallel to WiFi. Or, perhaps as our collective thirst for WiFi spectrum exceeds what the FCC can deliver, today’s WLAN industry players will coalesce as giant brain trust on LiFi and answer all of the challenging questions that wireless networking pros have today.

It’s just too early to tell where LiFi is really going. Yes, it is fascinating technology, and will likely have some role beyond downloading 18 movies a second a foot away from a LiFi access point.

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