9 tips for speeding up your business Wi-Fi

Is your company's lethargic Wi-Fi making users scream? Try these techniques for a zippier network

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6. Disable lower data rates and standards

Although 802.11n products support theoretical maximum data rates up to 450Mbps, and current 802.11ac devices up to 1.3Gbps, the APs may transmit as low as 1Mbps in 2.4Ghz and 6Mbps in 5Ghz for certain traffic. Generally, the further you travel from an AP, the lower the signal and the lower the data rate.

However, even if network coverage and signals are excellent, most APs by default send management or multicast traffic, such as the SSID beacons, at very low rates instead of at maximum data rates (as they do when sending regular data traffic). Increasing the minimum or multicast data rate of the APs can force management traffic to be sent at a faster rate, effectively decreasing overall airtime.

This technique can also help devices automatically connect to better APs more quickly. For instance, some devices by default may not look for another AP to roam onto until they fully lose the connection with the AP they're currently connected to. That might not happen until the device travels so far that the signal and data rate is at the minimum supported by the AP. So if you increase the minimum data rate, you'll basically shorten the maximum coverage area of each AP but at the same time increase overall network performance.

When disabling lower data rates, you can effectively disable the support of older wireless standards. For instance, if you disable all data rates at 11Mbps and below, that prevents the use of 802.11b devices, since that standard's maximum data rate is 11Mbps. For most networks, disabling 802.11b support is acceptable, but you might not want to fully disable the next standard: 802.11g, which tops out at 54Mbps.

There's no suggested minimum data rate that all networks should use; that decision depends upon the network's unique coverage and other factors. If you want a moderate change, perhaps try disabling 11Mbps and below. For a pretty aggressive change, consider disabling 48Mbps and below, which still allows the use of the most popular standards: 802.11a/g/n/ac.

the multicast data rate settings of an AP

Here's an example of the minimum or multicast data rate settings of an AP.

7. Properly configure channel widths

As touched on earlier, there are different channel widths that Wi-Fi can use. Generally, the larger the channel width, the more the data that can be sent at once, and the less airtime that will be used. The 802.11b/g standards support just the legacy 20MHz channel widths, 802.11n adds support for 40MHz, and 802.11ac adds support for 80MHz, with 160MHz coming in the future.

an AP that can be set to auto 20/40/80 channel widths

This AP can be set to auto 20/40/80 channel widths, while others may allow you to set only auto 20/40.

Given how small the 2.4GHz band is (and to support 802.11g), you'd want to keep the legacy 20MHz channel widths in that band. For 5GHz, consider using an auto-channel width setting. Though increasing to 80MHz only would allow for faster data rates with 802.11ac devices, that's not a good approach for most networks today because it would prevent dual-band 802.11n devices from connecting in that band.

8. Shorten packet sizes and transmission times

There are packet sizes and transmission times for certain traffic that can be reduced to help increase speeds and decrease airtime. If available on your APs, these can be changed in the advanced wireless/radio settings. Although you might only see a slight performance boost for each individual tweak, you could see a noticeable difference when combined.

  • If you don't have any 802.11b clients, you can enable Short Preamble Length to shorten header information on packets.
  • Enabling Short Slot Time can decrease the time for any retransmissions.
  • Short Guard Interval shortens the time it takes to transmit packets, which can increase data rates.
  • Frame Aggregation allows sending of multiple frames in a single transmission, but use with caution: This can cause compatibility issues with Apple products.

9. Upgrade older 802.11b/g clients

I already touched on how disabling support for older wireless standards can help increase the speed of management traffic and help force slow devices onto a better AP. But using older standards slows data rates for all traffic, even for devices using the newer standards.

If you have any devices on your network that support only 802.11b/g, consider upgrading to at least dual-band 802.11n, or preferably 802.11ac. Though upgrading the internal Wi-Fi of a laptop or desktop computer is usually possible, a quicker, easier method is to add a USB wireless adapter. They're painless to install and are relatively cheap these days — typically from $30 to $50 online.

Summary

Always remember that airtime is crucial on wireless networks. Though you might not necessarily want extremely fast Wi-Fi, reducing airtimes and increasing speeds might be required to support networks with heavy or dense usage.

If coverage is acceptable on your network, try the techniques I discussed first before adding or changing locations of APs. There might be a reason for the poor performance that should be addressed, or other ways to increase performance with simple setting changes.

Since there are so many variables with Wi-Fi, sometimes it's easy to blame wireless for problems that actually stem from general network issues. For instance, if the wireless is slow, the real issue could be with the Internet connection, or maybe even a misconfiguration like a low bandwidth limit on the APs. Thus you should also consider those general network issues when troubleshooting your Wi-Fi.

This story, "9 tips for speeding up your business Wi-Fi" was originally published by Computerworld.

Copyright © 2015 IDG Communications, Inc.

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