Wireless Access Point
350 Configuring the Wireless AP
Procedure for Configuring Global 802.11ac IAP Settings
1. 802.11ac Mode: Select Enabled to allow the AP to operate in 802.11ac 
mode. If you select Disabled, then 802.11ac operation is disabled on the 
AP. 
2. 80 MHz Guard interval: This is the length of the interval between 
transmission of symbols (the smallest unit of data transfer) when you are 
using 80MHz bonded channels. (See “80 MHz and 160 MHz Channel 
Widths (Bonding)” on page 48.) Select Short to increase the data 
transmission rate by decreasing wait intervals in signal transmission. 
Select Long to use the standard interval. The default is Short. 
3. Max MCS: Select the highest Modulation and Coding Scheme level that 
may be used with 1 or 2 Spatial Streams. For models with 3x3 radios, 
there is also a setting for 3 Spatial Streams. This setting may be used to 
limit the highest level of modulation to 64-QAM, or allow 256-QAM with 
its higher data rate. It also determines the coding scheme used for error 
correction. Higher MCS levels allocate fewer bits to error correction, and 
thus a higher proportion is used for data transfer. The default Max MCS
value is MCS9. 
The higher the MCS values, the higher the data rate, as shown in 802.11ac 
Supported Rates, below. Higher MCS levels require higher signal-to-
noise ratios (i.e., a less noisy environment) and shorter transmission 
distances. See “Higher Precision in the Physical Layer” on page 47.
The maximum number of separate data streams that may be transmitted 
by the antennas of each IAP is determined by whether the AP has 2x2 or 
3x3 radios. For a device that has 2x2 radios, such as the XR-620, the 
settings for three spatial streams are not shown. See “Up to Eight 
Simultaneous Data Streams — Spatial Multiplexing” on page 44.
4. 802.11ac Supported Rates: This list shows the optimum data rates that 
can be expected, based on the number of spatial streams that a station can 
handle, and on your settings for Max MCS, Guard Interval, and the use of 
bonded channels, up to 80MHz wide.