Default, Supported, and Recommended for Voice Device Settings

Besides those specific recommendations which would need careful examination, most of the device's default settings are already optimized for voice connectivity. For that reason, it is recommended to keep the defaults and let the device dynamically adjust the WLAN network dynamic feature-selection levels. Device configuration should change only if there are WLAN network (wireless LAN controller (WLC), access points (AP)) features that mandate respective changes on the device side to allow proper inter-operation.

Note the following:

Pairwise master key identifier (PMKID) is disabled on the device by default. If your infrastructure configuration is configured for PMKID, enable PMKID and disable the opportunistic key caching (OKC) configuration.
The Subnet Roam feature allows you to change the network IP of the WLAN interface when the network is configured for a different subnet on the same extended service set identification (ESSID).
In execution of default fast transition (FT) (also known as FT Over-the-Air), in case that other non-FT Fast Roaming Methods might be available on the same SSID, see Fast Roam Methods in Table 5 and relevant notes in General WLAN Recommendations.
Use mobile device management (MDM) agents to change settings. Use the user interface (UI) to change parameter subsets.
For voice applications, and for any highly-dependent client-server communication apps, it is not recommended to use the Android battery optimization feature (also known as Doze Mode) in device management tools. Battery optimization interrupts communication between dependent endpoints and servers.

Default, Supported, and Recommended Voice Device Settings

Feature	Default Configuration	Supported Configuration	Recommended for Voice
State11d	Country selection set to Auto	Country selection set to Auto Country selection set to Manual	Default
ChannelMask_2.4 GHz	All channels enabled, subject to local regulatory rules.	Any individual channel can be enabled or disabled, subject to local regulatory rules.	Device Mask matches the exact set of network side operating channels configuration. It is recommended to configure both the device and the network to a reduced set of channels 1, 6, and 11, if WLAN SSID is enabled on 2.4 GHz.
ChannelMask_5.0 GHz	All non-dynamic frequency selection (DFS) channels enabled, subject to local regulatory rules.	Any individual channel can be enabled or disabled, subject to local regulatory rules.	Device Mask matches the exact set of network side operating channels configuration. It is recommended to configure both the device and the network to a reduced set of only non-DFS channels. For example, in North America, configure the network channels to 36, 40, 44, 48, 149, 153, 157, 161, 165.
Band Selection	Auto (both 2.4 GHz and 5 GHz bands enabled)	Auto (both bands enabled) 2.4 GHz 5 GHz	5 GHz
Band Preference	Disabled	Enable for 5 GHz Enable for 2.4 GHz Disable	Enable for 5 GHz, if WLAN SSID is on both bands.
Open Network Notification	Disabled	Enable Disable	Default
Advanced Logging	Disabled	Enable Disable	Default
User Type	Non-Restricted	Enable Disable	Default
Cisco Centralized Key Management (CCKM)	Enabled	Enable Disable	Default
FT	Enabled	Enable Disable	Default
OKC	Enabled	Enable Disable	Default
PMKID	Disabled	Enable Disable	Default
Power Save	NDP (Null data power save)	NDP Power save polling (PS-POLL) Wi-Fi multimedia power save (WMM-PS)	Default
11k	Enabled	Enable Disable	Default
Subnet Roam	Disabled	Enable Disable	Default
11w	Disabled	Enable / Mandatory Enable / Optional Disable	Default or Enable / Optional
Channel Width	2.4 GHz - 20 MHz 5 GHz - 20 MHz, 40 MHz and 80 MHz	Not configurable	Default
FT Over The DS	Enabled	Enable Disable	Default
11n	Enabled	Enable Disable Note: Disabling this also disables 11ac.	Default
11ac	Enabled	Enable Disable	Default
11v	Disabled	Enable Disable	Enable