vCORE Technology Partners | Sept. 16, 2020
During recent conversations with customers, our engineers at vCORE have noticed a spike in questions about wireless networking. At first we were surprised, considering such a large portion of the workforce is working from home during the pandemic rather than tapping into corporate WiFi at the office.
But the truth is, while some of America’s largest companies are in no rush to reopen their offices, many other businesses have taken measures to safely and responsibly welcome employees back into the workplace.
Employees are indeed returning to work, but now with a different setup. Many of them don’t have a desk. At least, not their own, permanent workstation.
Instead, employees are often sitting at hotel desks that rotate among those working on-site each day, helping the company comply with social-distancing guidelines.
With offices running at 25-50 percent capacity, everyone is spread out. Everyone is truly mobile. And they’re typically connecting to the Internet via wireless network rather than a wired connection.
Another big change for office wireless — the type of traffic flowing in and out. Video conferencing is bigger than ever. Zoom, for example, grew from 10 million active users in January to 200 million in March. Providers are reporting an 80 percent increase in upload traffic over WiFi since the onset of the COVID-19 pandemic.
Considering the rapid changes and the importance now, more than ever, of providing steady, reliable wireless in offices and other business locations, vCORE’s own wireless expert, Michael Balasko, recently sat down (virtually) with customers to provide deeper insight into some best practices and challenges they’ll need to address in order to optimize their network performance.
Here are five common mistakes he sees, along with some insight into how to correct the problem:
1. Design for density, not coverage
As a general rule, an access point can cover 1,800 to 2,200 square feet an an open space — but those are figures that provide average to low throughput performance. If you’re expecting users to be at 400-600 mbps, that cell size has to shrink, and the AP density has to increase.
The “Coverage Model” in the above image indicates how many organizations have been designing wireless networks for the last two decades, with a small amount of overlap and coverage across the entire floorplan.
A dense cell coverage model, like the one seen on the right, however, provides numerous benefits. Secondary and tertiary signal strength is improved, which means the AP has multiple choices to roam to, so in the case of busy APs, there is more flexibility for the client. Roaming will be a lot more seamless, which is helpful for voice-over-WiFi calling.
The density also helps preserve client battery life, with less roaming and scanning required by the devices. Meanwhile, location services will provide more useful data in determining where people are throughout the building, where they are moving to, what the movement patterns are, etc.
2. Avoid maximum Tx power
A common strategy organizations in an attempt to boost wireless performance for client devices that are farther from the access point is to boost transmitting power for the AP.
The issue is that the clients typically only have a quarter of the power of the AP, so while the access point is screaming loudly to the client, the device is unable to respondb ack to the AP.
Meanwhile, as you increase the irradiated power from the access point, it starts to generate noise for other APs, tying up RF spectrum, bleeding into other channels and causing contention issues.
You want the lowest noise floor possible, so you want the APs as quiet as they can be for the particular clients that are in use. You want the signal strength to be -67 or below, depending on cell sizes.
So what is the right power for your access points? A good rule of thumb is to set it at half the max Tx power of your worst client.
3. Knock it off with the SSIDs
Creating too many SSIDs can also cause wireless network issues by creating management overhead, as the access point has to perform extra housekeeping on the back-end, in addition to scanning for clients and other APs.
The general recommendation is to have no more than three SSIDs per access point. That could include a primary network SSID, a guest SSID, and a separate SSID for legacy devices, for example.
If your organization falls into the trap of creating an SSID for every vendor, point of sale system, building system, camera system, etc., the APs get bogged down doing nothing but responding and generating management frames and can’t serve traffic.
4. Disable .11b data rates
Most environments won’t have active devices old enough to still be using 802.11b, but there are some instances to watch out for. Legacy devices that are expensive to replace — like blood transfusion pumps in hospitals, for example — aren’t updated as frequently and could be slowing down network performance.
In some cases there may be a firmware update that can at least move the device from .11b to .11g, which will help. Another trick to avoid this problem would be to disable all .11b data rates (1, 2, 5.5, 6, 9, and 11 mpbs) and move everything to 12 mbps and above.
This is really to try to ensure other devices in the cell are not hamstrung by one client that is connected at a much slower speed.
5. Optimize roaming with lesser-known features
We find a lot of these things are not enabled in networks today. Sometimes people are scared to turn them on or are just not sure what they do.
802.11k: Optimizes roaming by providing a neighbor report that helps a client find a closer AP faster. When this feature is disabled, a client that hits the roaming threshold after moving away from an access point may take around 6 seconds to scan other channels in search of a new AP. With the feature in play, however, the first AP provides a short list of neighbors that can reduce the scanning time to 200 milliseconds.
802.11v: This feature takes into account how loaded a certain AP is, how many users are connected, and how much traffic is moving through, and can send a client to a less-crowed nearby AP to boost performance.
More tips and best practices are included in the full version of the “Wireless Demystified” webinar. Complete the form below to get full access and/or request a follow up from vCORE’s network team.
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