Advanced AP Radio Settings

The purpose of advanced radio settings for an AP is to improve data packet throughput. Frame aggregation is a feature of the IEEE 802.11e, 802.11n, 802.11ac, and 802.11ax wireless LAN standards that increases throughput by sending multiple data frames in a single transmission. Frame transmission by an 802.11 device includes significant overhead. In fact, the overhead can consume more bandwidth than the payload itself. To address the overhead issue, the 802.11n standard offers MAC Service Data Unit (MSDU) aggregation and MAC Protocol Data Unit (MPDU) aggregation. Both types of aggregation result in a single frame. Management information is specified only once per frame; therefore, the ratio of payload data to the total volume of data is higher, resulting in greater throughput.
Note

Note

You can configure radio settings for all APs in a device group from the device group Radio tab and Advanced Radio dialog. And you can override radio settings for one or more individual APs from the AP Advance Settings > Override dialog.

Radio settings are dependent on the access point model.

Table 1. Advanced Radio Settings
Field Description
(Off Channel Scan)

OCS Channels
Note: Supported on Wi-Fi 6 AP models.
Define custom channel list:
  • Channels for Radio 1 are all 2.4 GHz or both 2.4 and 5 GHz lower band channels. Channel width is selectable.
  • Channels for Radio 2 are 5 GHz channels or 5 GHz upper band channels. Channel width is selectable.
  • Channels for Radio 3 (supported on the AP4000) are 6 GHz channels. See 6 GHz Channel Allocation and Notation for more information.
OCS Interval (DTIMs)
Delivery Traffic Indication Message (DTIM) interval must be between 2-100.
  • R1 5G-L — 5.15-5.35 GHz
  • R2 5G-H — 5.5-5.925 GHz
  • R2 5G-F — 5.15-5.925 GHz
  • R1 2G-F —Channel 1 to 13 (Channel 14 for Japan)
Supported on the following 802.11ax APs:
  • AP3000/X
  • AP310i/e
  • AP310i/e-1
  • AP360i/e
  • AP4000
  • AP4000-1
  • AP410i/e
  • AP410i-1
  • AP460i/e
  • AP505i
  • AP510i/e
  • AP510i-1
  • AP560i/h
  • AP5010
  • AP5020
  • AP5050U/AP5050D
LDPC Increases the reliability of the transmission resulting in a 2dB increased performance compared to traditional 11n coding.
STBC Space Time Block Coding. A simple open loop transmit diversity scheme. When enabled, STBC configuration is 2x1 (two spatial streams combined into one spatial stream). TXBF overrides STBC if both are enabled for single stream rates. Enable this setting when you anticipate single stream clients with lower RSS power.
Guard Interval Mode The guard interval is the space between characters being transmitted (not the space between packets). The default value is Auto, which is sufficient for most indoor deployments. Consider Long or Quadruple for outdoor deployments where devices are installed more than 100 meters away. Setting the Guard Interval to Long or Quadruple, gives each AP more time to detect the received signal, improving signal quality, but sometimes reducing signal throughput. Valid values are:
  • Auto
  • Long
  • Short
  • Quadruple

    Quadruple is the longest setting. It is applicable in 802.11ax mode only.

Note: Supported on Wi-Fi 6 AP models.
Airtime Fairness Mode Enabling Airtime Fairness organizes radio traffic allocating bandwidth to faster devices. If you have older devices on your network that are hogging bandwidth, consider enabling Airtime Fairness to give priority to faster devices.
Maximum Distance Increasing the Maximum Distance can give APs in an outdoor deployment more time to receive acknowledgment messages. For outdoor deployments, where APs are installed more than 100 meters apart, consider increasing the Maximum Distance setting up to 15000 meters.
Tx Beam Forming Tx Beam Forming is a technique of re-aligning the transmitter multipath spatial streams phases in order to get better signal-to-noise ratio on the receiver side. Support is based on AP model number:
  • AP 39xx — Available on the 5 GHz radio only. The valid values are: (multi-user) MU_MIMO and Disabled.
  • Wi-Fi 6 AP models — Available on the 5 GHz radio only. Valid values are (single-user) SU_MIMO, (multi-user) MU_MIMO, and Disabled.
  • AP4000 — Available on the 5 GHz and 6 GHz radios. Valid values are (single-user) SU_MIMO, (multi-user) MU_MIMO, and Disabled.
  • WIFI 6e and WIFI 7 APs — Valid values are:
    • Disable
    • DL_SU_MIMO
    • DL_MU_MIMO
    • UL_MU_MIMO
    • DL&UL MU-MIMO

SU-MIMO is limited to one pair of wireless devices simultaneously sending or receiving multiple data streams. MU-MIMO allows multiple wireless devices to simultaneously receive multiple data streams.
Radio Share Mode Radio operates as a sensor and a traffic forwarder. Valid values are:
  • Off. When the radio mode is set to Off, the Radio Share capability is disabled.
  • Inline. AP reports to the ADSP server only multicast / broadcast traffic such as beacons and probe requests. Inline mode has minimal impact on AP performance, because the AP reports to the ADSP server only traffic that it processes.
  • Promiscuous. AP receives all packets seen on its operating channel and forwards them to the ADSP server. Promiscuous mode loads the AP resources, because AP has to process all traffic in the channel. In high-density, wireless deployments, use dedicated sensors instead of Radio Share in Promiscuous mode.
    Note: Set AP to Promiscuous mode when AP is required to perform Termination.
In-Band Discovery In-band discovery mechanisms decrease the time for channel scanning the 6 GHz frequency band. This is advantageous due to the many channel options on the 6 GHz band.

FILS (Fast Initial Link Setup) — Designed for dense environments, FILS provides fast roaming without 802.11r. An FILS frame is analogous to a condensed beacon. Only critical information such as SSID, BSSID, and channel can be found in an FILS frame. The AP4000 sends this broadcast action frame out every 20 time units (TUs), approximately 20 milliseconds.

Supported on the 6 GHz radio band (AP4000). In-Band Discovery is disabled by default.
ADDBA Support Block acknowledgment. Provides acknowledgment of a group of frames instead of a single frame. ADDBA Support must be enabled if Aggregate MPDU is enabled.
Aggregate MSDU Determines MAC Service Data Unit (MSDU) aggregation. Enable to increase the maximum frame transmission size.
802.11g protection mode Enable this rate limit to prioritize 802.11g (ERP-OFDM) transmission allowing the 802.11g device to transmit unhindered. Protection is used when the packet rate is greater than the configured protection limit rate. For example, if the protection rate is set to 11Mbps, protection will be used when sending at rates greater than 11Mbps, which means 802.11g rates.

To maintain compatibility between the older (802.11b (HR-DSSS) and the newer 802.11g (ERP-OFDM) ) technologies, a mechanism was devised to enable the older 802.11b device to understand the newer 802.11g device without significantly lowering the data rate of the 802.11g client. The 802.11g device sends an RTS/CTS frame sequence (Request To Send/Clear To Send) that should be heard by all stations, it can also use only "CTS-to-self." This sequence is understood by the 802.11b station that reads the duration field from the frame and sets its NAV timer to hold off the medium until this timer expires. This allows the 802.11g to transmit unhindered. An AP notifies all clients within its service area that there are 802.11b devices present via a bit set in its beacons. Note: It is the newer protocol (802.11g) being protected from the older (802.11b) protocol.

The protection rate limit threshold determines when to use protection.
Minimum Basic Rate

Defines the minimum data rate that must be supported by all stations in a BSS (Base Station Subsystem):

  • Select 6, 12, or 24. The default value is 6.
Aggregate MPDUs Determines MAC Protocol Data Unit (MPDU) aggregation. Enable to increase the maximum frame transmission size, providing a significant improvement in throughput.
RTS/CTS Set to Enabled or Disabled. In some cases, disabling RTS/CTS can improve data flow because of fewer dropped control packets.
Aggregate MPDU Max # of Sub-frames Maximum number of sub-frames of the MAC Protocol Data Unit (MPDU) aggregation. The value range is 2-64.
DTIM When any single wireless client associated with an access point has 802.11 power-save mode enabled, the access point buffers all multicast frames and sends them only after the next DTIM (Delivery Traffic Indication Message) beacon, which may be every one, two, or three beacons (referred to as the “DTIM interval”).
OFDMA
Specify the direction to use Orthogonal Frequency-Division Multiple Access (OFDMA). Valid values are:
  • Off
  • DL— downlink
  • UL— uplink
  • Both

802.11ax APs use OFDMA technology to partition a channel into resource units, allowing users with varying bandwidth needs to be served simultaneously. OFDMA is ideal for low bandwidth applications. Its benefits include: better frequency reuse, reduced latency, and increased efficiency. When OFDMA is enabled, the AP mandates the resource unit allocation for multiple clients for downlink and uplink OFDMA. A series of trigger frames are exchanged to allow multiple-user transmission in the downlink and uplink directions. To avoid overlapping of OFDMA symbols, specify a guard-interval. OFDMA is disabled by default.

Supported on the following 802.11ax APs:
  • AP3000/X
  • AP310i/e
  • AP310i/e-1
  • AP360i/e
  • AP4000
  • AP4000-1
  • AP410i/e
  • AP410i-1
  • AP460i/e
  • AP505i
  • AP510i/e
  • AP510i-1
  • AP560i/h
  • AP5010
  • AP5020
  • AP5050U/AP5050D
BSS Color Configures support for 802.11ax BSS coloring and assigns the BSS color associated with the radio. BSS coloring is a means by which 802.11ax radios differentiate between overlapping Basic Service Sets (BSSs) in multi-path channels. A BSS represents a set of communicating devices consisting of one AP radio and one or more client stations. In an 802.11ax-enabled wireless network, each BSS is identified by a numerical identifier (the BSS color) added to the header of the PHY frame. BSS coloring impacts channel access behavior and spatial reuse operations. Based on the BSS color detected, APs can assign a new channel access behavior. Spatial reuse is another advantage of enabling BSS color. It applies adaptive Clear Channel Assessment (CCA) thresholds for detected Overlapping BSS (OBSS) frame transmissions, which enables APs to ignore transmissions from an OBSS and transmit at the same time. BSS color support is disabled by default.
Supported on the following 802.11ax APs:
  • AP3000/X
  • AP310i/e
  • AP310i/e-1
  • AP360i/e
  • AP4000
  • AP4000-1
  • AP410i/e
  • AP410i-1
  • AP460i/e
  • AP505i
  • AP510i/e
  • AP510i-1
  • AP560i/h
  • AP5010
  • AP5020
  • AP5050U/AP5050D
Target Wake Time Enables 11ax Target Wake Time (TWT) support on the radio. The IEEE 802.11ax standard defines power-saving enhancements and improved resource scheduling features, such as scheduled sleep and wake times. TWT allows devices (APs and stations) to negotiate when and how frequently they will wake up to send or receive data. TWT increases device sleep time, thereby substantially improving the battery life of the client device. TWT is enabled by default.
Supported on the following 802.11ax APs:
  • AP3000/X
  • AP310i/e
  • AP310i/e-1
  • AP360i/e
  • AP4000
  • AP4000-1
  • AP410i/e
  • AP410i-1
  • AP460i/e
  • AP505i
  • AP510i/e
  • AP510i-1
  • AP560i/h
  • AP5010
  • AP5020
  • AP5050U/AP5050D
Cell Size Control
Probe Suppression on Low RSS Reduces the number of probe responses by preventing clients with low RSS from associating with an AP radio. This setting is configured per radio. Clients with RSS measured below the Probe Suppression RSS Threshold will not associate with the AP. This setting is disabled by default.
Probe Suppression RSS Threshold (dBm) This setting is available when Probe Suppression on Low RSS is enabled. This setting determines the RSS threshold for forced disassociation and probe suppression. The default threshold is -90 dBm. Valid value range is -50dBm to -100dBm.

Best Practice: Probe Suppression Threshold should not be greater than -70dB. The Probe Suppression Threshold defines the signal strength value that is deemed too low to be acknowledged by the AP. Setting the threshold above -70dB can result in an AP not acknowledging clients in close proximity, leading to poor connectivity or a sub-optimal roaming experience. The best practice is to follow the Site Survey methodology to determine the best value for the AP installation.
Disassociate on Low RSS This setting is supported on AP39xx, AP3xx, AP4xx, or AP5xx. It is always disabled by default. This setting forces clients with low RSS to disassociate from an AP radio. This setting is configured per radio. A client is forced off an AP radio when RSS is measured at 5dBm below the Probe Suppression RSS Threshold. Enabling this option forces a client to roam to a better AP for improved network performance.
Probe Response Retry Limit The default Probe Response Retry Limit is 4. If devices are having a problem connecting to the network, due to congestion or due to the quality of the device, consider increasing the retry limit. Maximum value is 10.
Rx Sensitivity Reduction (dB) New APs are very sensitive and can pick up unwanted channel interference. If this is an issue, add an offset of 5-10 dB, which will reduce signal sensitivity and improve signal quality.
Multicast to Unicast Delivery
Converts multicast transmission to unicast for backward compatibility. Valid values are:
  • Disable — Transmission is not converted.
  • Auto — Multicast transmission is converted to unicast for the selected AP radio.
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