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WiFi Design Considerations For K-12 Schools

With Wi-Fi maturing and vendors releasing new WLAN product lines, there comes a time to refresh the existing WiFi network. For K-12 schools, WLAN upgrades can be particularly challenging. They're not only faced with upgrading a legacy wireless network built to handle old requirements for simple coverage, but a tight budget makes selection of WLAN hardware difficult. Moreover, students and teachers rely on critical applications such as Web-based interactive learning programs and high-definition video, which require a lot of bandwidth.

To obtain a good return on investment, schools must conduct extensive planning to create a comprehensive WiFi design. Upfront planning will ensure end user requirements are met and save a school from wasting money on unnecessary equipment.

Coverage and capacity

Previous wireless designs were based on coverage as the only requirement. With faster devices on the market and constant connectivity, older WLANs are no longer capable of managing the capacity required for interactive learning videos and web applications.

In a new WiFi design for K-12, focus on meeting capacity requirements. Coverage is always a requirement, but what is more important is the focus on application requirements. Determining application throughput needs helps identify the number of access points needed.

In school environments, you'll often hear about a 1-to-1 design, which is one access point (AP) per classroom. This is simply vendor marketing, and a costly mistake that eats into a school's limited budget. One access point is capable of servicing more than the number of devices in a typical classroom. Why spend extra money when an access point can be configured for efficiency?

The one-AP-per-classroom design can lead to poor WiFi performance without proper tuning. Having too many radios turned on can cause interference, which will degrade a wireless network.

Devices

Wireless networks are designed to meet the needs of wireless devices. This makes selection of laptops, tablets, and other mobile devices very important.

Avoid buying 2.4GHz-only devices. Ensure they are dual-band, meaning they support both 5GHz and 2.4GHz.

After those devices have been installed, be sure to keep the WiFi drivers updated. Often times, drivers are updated to fix issues with algorithms, improve algorithms, and even fix bugs that negatively affect a user's experience.

With many devices to manage and deploy, it makes sense for schools to automate the management of devices. Mobile device management (MDM) is a time saver for many schools.

Identify how many devices require WiFi access to include in capacity planning.

BYOD

In addition to the school-provided devices, students, faculty members, staff, and parents will oftentimes bring in their own devices.  Without knowing what kind of devices will be joining the network, it is important to focus on meeting capacity requirements.

Many high school and middle school students carry on average two to three devices, and often use them simultaneously. Estimate the number of visitors joining the network and, in specific areas, think about designing for higher capacity.

An automated on-boarding system is required to fully control guest devices on the network such as throttling, registration (if needed), and URL filtering.

Although schools can use tools and settings to isolate guest users, sometimes the best practice is a zero-barrier entrance for guest users. Allowing guest users onto guest Wi-Fi without a portal eliminates user confusion and connectivity issues.

Antenna selection

Typical installations utilize omnidirectional antennas built into an access point. This propagates WiFi in a 360-degree fashion. However, WiFi signals travel very far. To control this signal and provide better performance to devices I recommend using directional antennas instead of omnidirectional ones.

Directional antennas help decrease interference between other access points because the signal covers a specific area compared to an omnidirectional antenna. Decreasing interference and creating smaller wireless cells improves performance.

Infrastructure

Legacy WiFi access points were powered up via Ethernet cabling based on the 802.3af protocol. A switch port with an access point on the other end can power the AP with up to 15W of power. Now, new access points require more juice, up to 30W. Power over Ethernet (PoE) requirements should be taken into consideration when designing a new WiFi network.

Switches may need to be upgraded in order to support the influx of access points. In addition to switches, you might need to run new cabling between the network closet and the access point locations. Lastly, a wireless network will run slow if your pipe out to the Internet is not fast enough to provide bandwidth to all users.

Altogether, don’t forget to budget for the wired side of the network, which connects all of the wireless.

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