Large campus network: best practices for Airplay (+ issues with lots of Apple TV's)

[pieter_schepens]

We have a large campus network: ZoneDirector ZD1200, ± 50 AP's R500 and R510, ± 100 Apple TV's, lots of iPads (1:1 and shared iPads). The Apple TV's and iPads are on the same SSID, but in small VLAN's/subnets. The backbone of our network has high performance. WiFi speed and reliability are perfect.
We use AirPlay mirroring to the Apple TV's to cast the screen of the teachers iPads to the projector or TV screen. We don't use Bonjour Gateway. From time to time, we experience drop outs or lag in the Airplay streaming. 

We'd like to know, when configuring a WiFi network for AirPlay with lots of Apple TV's:

• What are the best WLAN settings?
• What are the best settings for things like self healing, background scanning, load balancing, etc...?
• What are the best settings for the AP's?
• Any other best practices to make AirPlay reliable?

Any help or advice is greatly appreciated.

 

[pieter_schepens]

Regarding the power settings of the two radios, what would you suggest (large campus, dense network, lots of Apple TV's, peer to peer Airplay):

• Enable the setting "Automatically adjust AP radio power to optimize coverage when interference is present"? Some people recommend it, but the documentation says: "In general, Ruckus does NOT recommend enabling this feature as it can lead to sub-optimal AP power levels."
• Adjust the power manually on the AP's by adjusting TX Power (to min or to another low level?)? Only on the 2.4Ghz band, or also on the 5GHz?
• Or disabling the 2.4Ghz altogether?

May the wisdom of power be with you.

[michael_brado]

Our Gurus say to leave AP tx power at maximum. 

You have found that Airplay (based on Bonjour) is a very chatty LAN based broadcast protocol,
and limiting clients/services from creating a broadcast storm on few VLANs is important.

Please see some KBAs with advice on Bonjour Gateway and known limitations, etc.

https://support.ruckuswireless.com/articles/000004258

https://support.ruckuswireless.com/articles/000006217  (will be visible after 6pm PST 12/9/19)

[john_d]

it's worth mentioning that newer Apple devices all use P2P Airplay which no longer goes through Bonjour, and uses bluetooth for beaconing and P2P wifi for the bandwidth heavy use. Airplay uses channel 149 in 80MHz mode for P2P wifi (same with AirDrop) so if you have a ton of Apple devices, it's best to use other wifi channels.

Here's a good article summarizing these findings: https://it.bytea.net/2018/airplay-in-enterprise-networks/

[brian_powers]

@Michael,

You said "Our Gurus say to leave AP tx power at maximum."

Is there some public document that goes into details around the "whys" of this?  This is a bit different than the industry norm of trying to match the output power of the AP with the client devices.  A higher AP output power also causes much larger ACI/CCI footprints that could lead to decreased WLAN performance.  And BeamFlex is not the right answer here TBH.  Management and Control frames are not BeamFlex'd IIRC and those frames that are Tx'd all include the same duration values/NAV timers that would cause contention in the entire RF cell for the AP which would be the source of the added ACI/CCI.

Thanks

[michael_brado]

Touche Brian, environment drives the design.  "Typically" is a much better adjective.  Examine AP coverage overlap and manage location or power levels to prevent over-saturation.  If you have mission critical devices that do not have equal Tx power, you may need to decrease APs to match.