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9 Myths About Wi-Fi in K-12 Education

June 20, 2017

9 Myths About Wi-Fi in K-12 Education

June 20, 2017
Brought to you by Ruckus Wireless

 

Squint a little bit—and ignore the lack of color-coded pajamas—and the modern classroom might as well be Starfleet Academy (go watch Star Trek if you don’t get the reference. It is great). Faculty and students tapping away at their touchscreens and interactive digital learning platforms. 4K video and collaboration connecting students to content and people everywhere in the world. Lighting, security cameras, thermostats, and a hundred other devices all networked together in smart classrooms and campuses.

Primary education is becoming a bold new frontier where no one has gone before. The growing use of Wi-Fi in public education is playing a big part in making this new frontier a reality. And while it’s easy to get caught up in the sci-fi vision of tomorrow, school IT administrators face more mundane—and much more pressing—questions right now:
WE’VE IDENTIFIED NINE COMMON MYTHS ABOUT SCHOOL WI-FI DEPLOYMENTS. AVOID BUYING INTO THEM, AND YOUR SCHOOL AND DISTRICT WI-FI WILL EXCEED YOUR EXPECTATIONS.

 

WANT TO BOOST YOUR WI-FI SPEEDS? YOU’LL NEED TO REPLACE YOUR WIRED SWITCHES.

Almost all fancy new classroom technologies—laptops, tablets, digital learning applications, online games and apps—now connect over the Wi-Fi network, and they’re chewing up huge amounts of bandwidth. It’s a good thing that new wireless technologies, like 802.11ac, can deliver big increases in throughput—you’re going to need every bit of it. But that wireless traf-fic must go somewhere, and at the end of the day, it all lands back on your wired infrastructure. Consider that the future holds more devices in the classroom, more digital curriculum, and more IoT endpoints, and you might as well just accept that you’re going to have to continuously rip and replace your wired network to keep up, right? Not exactly. It’s true that growing wireless traffic is putting pressure on schools’ wired infrastructures. According to the 2016 Funds for Learning E-Rate Trends Report, 65 percent of school IT administrators expect their bandwidth demands to grow by 50 percent or more in the next three years, and a quarter of respondents expect demand to double in the same period. Consid-ering schools typically update their wired infrastructure every six years, bandwidth demands could quadruple before the next refresh cycle.

It’s easy to look at the numbers and think that there’s no good way to close the gap. You could vastly over-provision your wired infrastructure to handle six years worth of escalating demand (because most schools have extra cash laying around for projects like that, right?). Or, you could just reassign yourself to overhauling the wired network every few years.
There’s a better option. You don’t have to spend more, just spend smarter. New switching platforms are built to be scalable, allowing for continuous bandwidth upgrades without a rip and replace.

 

ONE AP PER CLASSROOM PROVIDES OPTIMAL PERFORMANCE.
It’s a common misconception in many areas of life — not just Wi-Fi — to think that throwing money at a problem will solve it. Just like having the highest payroll in baseball the last few years didn’t buy the Dodgers a title, buying access points (APs) like they’re going out of style won’t necessarily translate to better performance. In fact, extravagant, over-deployed Wi-Fi net-works consistently prove inferior to measured, inclusive installations.
Why? Because adding APs to a Wi-Fi deployment can add capacity to a point, but add too many and they become count-er-productive. When you over-deploy APs, you increase the likelihood of more than one AP communicating with the same device over the same channel— (a phenomenon known as co-channel interference) which degrades performance.

Imagine standing in a classroom running the wireless scan function on your iPad. Your device would see the AP in the room you’re in, as well as the AP in the room(s) next door, all operating on the same channel at a signal above -80 dBm. For devices using the 2.4 GHz frequency band (the band with the broadest support among consumer devices), there are only three non-interfering channels available in North America. So, if you have APs installed in every classroom, it’s a virtual certainty that your users’ smartphones, tablets, and laptops will “see” more than one AP covering the same channel, leading to device interference. Picture driving to work, listening to your favorite song on your local radio station, when you hear another song cut in from a different radio station that’s broadcasting over the same channel—it’s the same kind of interference messing with your Wi-Fi connections.

For Wi-Fi installations in school environments, some APs are configured with low transmit power settings in order to give the illusion that over-deployment has been avoided. Don’t fall for this. Wi-Fi is a two-way communication technology (meaning that smartphones, tablets and other Wi-Fi devices must transmit to APs, as well as receive). So, if you have a high concentration of users (like in a typical classroom), decreasing AP transmit power won’t prevent co-channel interference. Don’t create new problems for yourself by buying into the “one AP per classroom” myth. The best way to really get the best performance? Commission a properly done site survey before choosing AP installation locations. Site surveys can be expensive and time-consuming, but a skilled integrator will save you both time and money in the long run by helping you get the best coverage and capacity for your school.

 

CLOUD-MANAGED WI-FI MAKES IT SIMPLE TO DELIVER A GREAT WI-FI EXPERIENCE.
It’s tempting to hear “cloud-managed wireless LAN” and assume that all of the complexities of a traditional wireless network magically go away. Just hand everything over to those wizards in the cloud, and your infrastructure will now work all day, every day, no matter what you throw at it. Unfortunately, that’s not quite the case.

Here’s the thing: cloud management does exactly what the name says: manage your Wi-Fi infrastructure. And it does a great job of it, but most of the problems that lead to poor wireless performance (slow connection speeds, dead spots, disconnects, and more) have nothing to do with management. A streamlined management interface won’t eliminate sources of interference in your airspace, make your wireless signals travel more consistently through brick or concrete, or let you support more clients with the same infrastructure.

At the end of the day, your ability to deliver a great Wi-Fi experience comes down to the technology you use at the point where devices connect—in the APs on the wall or mounted on the ceiling. Managing those APs from the cloud can make life easier for onsite IT staff, but it doesn’t make performance problems go away. Here’s a dirty little secret: it can actually make them worse. That’s because some cloud-managed Wi-Fi solutions, aiming to keep prices as low as possible, cut corners in their APs. They use off-the-shelf board designs from contract vendors and lowest-common-denominator antennas. No matter how much people might love the management software, it is still chained to sub-optimal AP technology. And unlike the cloud software, which can be updated at any time, once an AP is deployed, that’s the antenna and RF ability you get for its years of service.
Fortunately, the newest generation of cloud-managed Wi-Fi solutions don’t force you to make those trade offs. Some of the latest cloud Wi-Fi architectures and AP designs can provide the high performance and reliability you need, while allowing for simple deployment and management through the cloud. So, while the notion that cloud management will make all your problems go away really is a myth, it is indeed possible to have the best of both worlds. You can marry best-in-class AP per-performance with simple cloud-based management. And if you’re considering moving to the cloud, you should demand nothing less.

 

WAVE 2 APS WON’T HELP WITHOUT WAVE 2 CLIENTS.
Standards have always been a big deal in Wi-Fi, and the recent top dog is 802.11ac Wave 2. The 802.11ac standard was officially approved by the IEEE back in 2013, and 802.11ac APs and devices have been available even before that. The prob-lem is that — up until recently — everything was 802.11ac Wave 1. The technological explanation of 802.11ac Wave 1 can get a bit complicated, but essentially it is just 802.11n (the previous IEEE standard for Wi-Fi, which dates back to 2009) with a couple of enhancements for consumer Wi-Fi. (This is not to say that 802.11n and 802.11ac Wave 1 hardware is equivalent. The chipsets for 802.11ac Wave 1 are more modern than the chipsets for 802.11n, and chipsets matter).

802.11ac Wave 2 is now available, but it will be a while before it becomes the dominant Wi-Fi technology for users. Most APs now support 802.11ac Wave 2, and a growing number of new smartphones, tablets, and laptops do as well. But many still don’t—including Apple devices, which are notorious for implementing new Wi-Fi standards late.
It is this lack of available Wave 2 devices that has caused this myth to propagate. “Without Wave 2 de-vices, it doesn’t make sense to deploy Wave 2 APs,” or so the thinking goes. But it is a half-truth. Yes, the benefits of Wave 2 will only be fully real-ized once Wave 2 devices are widely available. No, Wave 1 APs do not deliver the same performance as Wave 2 APs, even if the connected devices are all 802.11ac Wave 1 (or 802.11n, for that matter).

First, the negative: 802.11 Wave 2 devices still make up a relatively small percentage of the wireless devices in use today. If you deploy Wave 2 APs in a high school, most smartphones and tablets used by students and faculty will still max out at the same data rates as if you’d deployed Wave 1 APs. Also, some devices may never use some of the new standard’s more intense performance-enhancing protocols, like Transmit Beamforming (TxBF) and Multi-User Multiple Input, Multiple Output (MU-MIMO), because they can have side effects like more channel overhead or shorter device battery life.

But here’s the thing: just because a lot of your users’ smartphones and tablets won’t use all of the enhancements of 802.11ac Wave 2, it doesn’t mean that their devices won’t benefit from a Wave 2 upgrade. 802.11ac Wave 2 APs use a more modern chipset, which offers better receive sensitivity than Wave 1 APs. This means fewer pesky half-connections (those connections where the device shows that it’s connected, but can’t get consistent access to the network) and, ultimately, greater range. Wave 2 APs also have more antennas, which can improve Wi-Fi conditions via enhanced receive diversity, even when con-nected devices support only 802.11ac Wave 1 or 802.11n.
It’s also worth noting that just having newer technology—even apart from 802.11ac Wave 2—does provide value. Later-gen-eration APs support newer connections, such as 2.5GbE ports, or USB for IoT dongles, that let you add things like Bluetooth LTE location services or power peripherals (such as a video camera mounted on the same pole as the AP). Advances like these have nothing to do with 802.11ac Wave 2, but they’re unlikely to be included on APs using previous-generation radio technologies. So, there are a few good reasons that Wave 2 APs are better than Wave 1 APs, even though full Wave 2 won’t be realized until more devices support it.

 

KEEPING STUDENTS’ SMARTPHONES OFF THE NETWORK IMPROVES WI-FI PERFORMANCE.
There are two tiers to the argument that students’ devices should be kept off school Wi-Fi networks. First: they use Internet bandwidth. Second: they don’t support the same high Wi-Fi speeds that tablets and laptops do, which are often used for education.

The argument that student smartphones’ use of internet bandwidth will affect network performance is sound in some ways, and flawed in others. All elementary, middle and high schools have a finite amount of Internet bandwidth coming in and going out. If students use their smartphones on the school’s Wi-Fi network for non-education activities, that leaves less available Internet bandwidth for education. Yet, the vast majority of Internet traffic is bursty, and therefore the total available bandwidth from the service provider is almost never used. Of course, at some point, a school’s Internet connection could become truly saturated; but it would be a rare case and a fixable problem (albeit at an additional cost paid to the Internet service provider).

The Wi-Fi side of the anti-smartphone argument is deceptive. Yes, smartphones do support lower maximum Wi-Fi speeds than tablets and laptops. Yes, low Wi-Fi speeds from one device can slow down a Wi-Fi channel for other devices. Yes, Wi-Fi is a technology that operates over a shared channel, meaning that when more devices use a channel, each individual device has less available access. All of that is true, but all of that is also specious. Prohibiting students from connecting to a Wi-Fi network does not keep their devices off the Wi-Fi channel. Unconnected Wi-Fi devices use the Wi-Fi channel via a process called Probing (in some circles, Probing is also called Discovery or Active Scanning). Devices use Probing to gather infor-mation about nearby APs. But, when a device is connected to a Wi-Fi network, it doesn’t need to gather information about nearby APs because it already has an AP (unless the device is roaming, but that’s another topic for another paper). When a device is unconnected to Wi-Fi, then it needs to search for APs that are nearby.

The problem with Probing is that it can—and often does—take up more Wi-Fi channel time than actual network data. Probe Request frames (a.k.a. “packets”) are sent at extremely low rates (either 1, 2 or 6 Mbps, depending on the device and operat-ing system), which means that Probe Request frames use up a disproportionately large amount of channel time. Therefore, low Wi-Fi speeds (in this case, from Probe Request frames) can slow down a Wi-Fi channel for all devices.

In most cases, one method for getting optimal performance out of school Wi-Fi is to allow students’ and employees’ person-al devices to connect to the network. But what about security? Well, there is a myth about Wi-Fi security, too…

 

WI-FI IS THE WEAKEST LINK IN SECURING STUDENT DATA PRIVACY.
Let’s start with what’s not a myth: protecting student data is a big challenge—and it gets even bigger the more schools embrace connected classrooms and personalized learning. With new devices, connections and applications comes a huge amount of student data that you’re now responsible for, including identification numbers, addresses, test scores, disciplinary records, information about special needs, and assistance programs. That data is now practically everywhere, both at rest (in databases and servers) and on the fly (traversing connections between devices and networks, school sites, data centers and the cloud).

If that sounds like a big, scary security challenge, it is. Under federal law, school districts can be held liable for not taking reasonable measures to protect against a data breach. Even worse, schools that fail to secure student data risk seeing their names in the headlines. You too could see your face on the news, getting peppered with unpleasant questions about what went wrong and why you failed!
So yes, securing student data is a big deal. But let’s get to the myth part: Wi-Fi is not the weak link in your security. Wi-Fi security is among the strongest mechanisms available today. If you’re using WPA2 EAP-TLS encryption for all wireless traffic (and you should be), you’re protecting your data with the gold standard in wireless security, using an encryption algorithm that’s never been cracked. Therefore, you can rest assured that—as far as hackers pulling confidential data out of the air—your Wi-Fi is at least as strong, if not stronger, than your wired network.

That doesn’t mean there aren’t big challenges involved with securing all those new student and faculty devices. If you’re still relying on MAC authentication and pre-shared keys—and if you’re still using passwords as a major line of defense—you may be in for a world of hurt. MAC addresses can be easily spoofed. Pre-shared keys are… well… shared. And passwords rely on people not using the same password across all their devices and apps, not storing their passwords where others can see them, and not forgetting them. Unfortunately, people really are the weak link in your security. According to the Intel Security Report Grand Theft Data, nearly half of all school data breaches came from inside the organization, and half of those were accidental.

A great firewall isn’t going to solve this problem. Strong encryption won’t solve it either. What you need is a way to ensure that only authorized devices and users can access sensitive information in the first place. To do that, you should be using certificate-based access (instead of passwords) for all school- and student-owned (BYOD) devices. In addition, your certificate framework should be tied to sophisticated identity and policy management, so you can control who is able to access what at a granular level.

 

UPGRADED POE IS NEEDED WHEN UPGRADING APS.
Let’s begin with a non-myth (a.k.a., truth): With new standards come greater power requirements. When 802.11a became pop-ular, dual-radio APs began being used. The additional radio required more power. When the 802.11n standard added MIMO, multiple radio chains became commonplace, thus increasing AP power requirements again. When 802.11ac Wave 1 made three-stream MIMO commonplace, it led to APs needing even more power. Now 802.11ac Wave 2 is here, and its support of four MIMO streams (and possibly up to eight streams in the future) has increased AP power needs again.

Where things get tricky is when someone suggests you need to upgrade your wired switches to support newer Power over Ethernet (PoE) standards. It’s true that the newer 802.3at (PoE Plus) supports an extra 12W of delivered power per port (25W, to be exact), but APs can still function when connected to switch ports that only support the older 802.3af PoE standard
(which supports 12.95W of delivered power).

 

INCREASING AN AP’S TRANSMIT POWER INCREASES COVERAGE.
To understand our eighth myth, the term “coverage” must first be defined. There are three choices- we’ll let you decide which:

1. Coverage = devices can see the Wi-Fi network.
2. Coverage = devices can see and connect to the Wi-Fi network.
3. Coverage = devices can see, connect to, and consistently access the Wi-Fi network.

OK, we lied. We’re not going to let you decide. The correct definition of coverage is number three.  Wi-Fi “coverage” simply isn’t coverage unless devices can consistently access the Wi-Fi network. And, while increasing an AP’s transmit power makes it more likely to consistently send data to devices, it does absolutely nothing to make it more like-ly to receive data from devices. That’s because increasing AP transmit power does not increase device transmit power. And without an increase in both, true coverage won’t be improved. In fact, some devices actually reduce their transmit power when connected to a more powerful AP, thus creating worse coverage. The device may see a super-strong signal and naturally reduce its transmit power in an attempt to prolong battery life.

 

BAND-SELECTABLE AP RADIOS IMPROVE PERFORMANCE.
There are some things in life that make sense until they actually happen. Take the Run & Shoot offense — a mercifully de-ceased American football system created in the 1980s. The Run & Shoot was designed to play the game as fast as possible, with ample room for improvisation. The designers of the Run & Shoot found that statistically, football teams scored more often when they didn’t use play-calling “huddles” that slow the game down. They also found that pre-designed plays could sometimes be predicted by the opposition, thus nullifying their effectiveness (players of early football video games became aware of this to great effect). Thus, huddles were eliminated, and players were asked to improvise, rather than running pre-de-signed plays. And it worked beautifully… until it was tested at the professional level. The Run & Shoot lasted only a couple of seasons in the NFL before its proponents were relegated to the lower levels of American football.

What went wrong with the Run & Shoot? Essentially, its designers focused on the positive and overlooked the negative. The Run & Shoot was effective at speeding the game up and making it more difficult for the opposition to predict plays. Unfor-tunately, speeding up the game reduced the amount of time defensive players had to rest, and using improvised plays didn’t work so well when large, angry men from the opposing team were rushing the backfield and planting them on the turf.