The recommendations for optimizing wifi for Apple devices resulted from a series of conversations with a good friend of mine, Alby*, who works with schools in Texas. All comments were specifically made in relation to tuning 802.11ac gen 2 APs from Aruba. However, this list provides some excellent guidelines when tuning or optimizing other networks too. We certainly found them to be helpful. Please take any recommendations with a grain of salt and review pertinent documentation from your wireless vendor regarding best practices. Wifi performance can have a significant impact on technology deployment and day to day operations. It’s critical to get it right.
Recommendations for Optimizing Wifi for Apple Devices
It may be helpful to consider collaborating with a wireless vendor to have a wireless site survey (Heat Map) completed of the buildings in the district, to show current Wi-FI AP misconfigurations, channel overlap, and radio broadcast power issues. They can often help determine the current issues and make suggestions for correction. Once the corrections have been completed to the APs, a follow-up Heat Map should be completed, to see if any additional tweaking is needed. Many vendors have heat mapping tools built into the controller or management interface. Additionally, 3rd party vendors like Ekahau offer excellent heat mapping tools that are detailed and robust.
Basic Recommendations for Tuning:
The steps below represent some basic steps to take when optimizing the network for Apple devices. From personal experience, ignoring some of these recommendations can make the wifi environment behave erratically. As more and more devices rely on this critical infrastructure, airspace can frequently become crowded. Thus Alby recommended, and we implemented, the following adjustments with good success.
– Turn off OKC (Opportunistic Key Caching)
– Decrease the total number of SSIDs that are being broadcast by the APs & remove hidden networks
– Use 40Mhz wide channels instead of 80Mhz, which will allow for more unique 5GHz channels available on your APs
– Use DFS Channels
– Design for -65dBm cell edge for SSIDs
– Scope APs to have unique channels, and avoid channel overlapping in close proximity
– 2.4 GHz radios should be tuned 6db lower than the 5GHz radios
– Configure each AP to not have the radios broadcast at 100% power, unless necessary (site survey will determine at what strength each AP should be configured) – Disable broadcasting on 5GHz 149 & 153 on your APs, to optimize peer-to-peer AirPlay from the Apple TVs, as documented here: https://help.apple.com/deployment/ios/#/apd8fc751f59
– Strongly consider using 5GHz only for your school-owned devices (primary SSID)
– Strongly consider using 2.4GHz for your Guest network SSID
– Turn off any Printers that may be broadcasting a Wi-FI setup (typically in the 2.4 GHz spectrum)
– Be aware that cell phone Hot Spots broadcast in the 2.4GHz spectrum
Content Caching
“Deploying one or many Apple Content Caches in a network will reduce Internet bandwidth usage (when downloading Apple related content) thereby reducing the saturation of the Internet connection for any network clients.”
Obviously caching server does not directly impact WiFi performance but the effects of having a caching server means that WiFi connections to the Internet will likely be on less saturated connections because there will be less people using bandwidth to download Apple content.
Here are some Cisco-specific suggestions for Optimizing Wifi for Apple Devices, that should apply to other APs as well:
Cisco has great recommendations for stabilizing wifi environments. In Eanes, our teachers utilize technologies like AirPlay mirroring, peer to peer networking with apps like Apple Classroom, and multimedia in the form of video and audio streaming on a daily basis. Sometimes school ISDs seem more like ISPs (Internet Service Providers), where uptime extends from early in the morning, well into the evening.
– Set Minimum Data Rate to 12 Mbps
– Enable 12 and 24 as Mandatory Rates
– Design for signal-to-noise ratio of 25 dB or better
– Keep Retry rates of less than 15%
– Keep Layer 3 packet loss of less than 1%
– Keep Jitter less than 100ms
– Average Channel Utilization of less than 40% – target less than 30%
– Turn on support for 802.11r – Fast Transition
– Turn on support for 802.11k – Neighbor Reporting
– Turn on support for 802.11v – BSS Transition Management
– Apple devices will not scan for new access point until their associated AP’s RSSI drops below -70dBm (this is why Apple devices can sometimes seem “sticky” from a wifi perspective)
– Set WMM On
– Set AVC on – set Voice QoS to Platinum
Cisco Guides for Optimizing Wifi for Apple Devices (may translate to other vendors)
https://www.cisco.com/c/dam/en/us/products/collateral/wireless/white-paper-c11-738125.pdf
Apple TV Basic Deployment Tips
*By conversation, I mean this is stolen from Alby’s work. He’s the brains behind this post!
