Wireless Access

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[TUTORIAL] [ArubaOS 6.3 and Above] [802.11ac] - Enable VHT even if you are running 20mhz channels

It is well known that 802.11ac produces high data rates, and most people assume that you can only take advantage of higher rates when you are running 40 or 80mhz channels.  Some people cannot run 40 or 80 mhz channels due to their high density requirements.   Enabling Very High Throughput (VHT) on your 802.11a radio profile even when running 20mhz channels will also increase performance for 802.11ac clients that are connecting to those same 20mhz channels:

vht.png

Here is the output of two devices connecting to an access point running 20mhz channels with VHT turned off (802.11n or HT is turned on):  One is 3 spatial stream 802.11ac MacBook Pro and the other is a single spatial stream 802.11ac smartphone:

vht-before-2.png

 

Note the  TX and RX rates of those two devices when VHT is turned off:

 

vht-before-1.png

 

When VHT is enabled, there is no change in channel width, but we recognize clients that can take advantage of 802.11ac when VHT is enabled and we put VHT in the phy type column:

vht-after-1.png

 

Both of those clients also receive a bump in their TX and RX rate when VHT is enabled:

vht-after-2.png

 

The access point is only running 20 mhz channels, but just enabling VHT in the 802.11a radio profile will give a boost to 802.11ac capable clients connecting to an 802.11ac access point with VHT enabled.

 

(host) #show ap ht-rates bssid 00:1a:1e:1e:5a:10
 
AP "AL12" Radio 0 BSSID 00:1a:1e:1e:5a:10 High-throughput Rates (Mbps)
----------------------------------------------------------------------
MCS  Streams  20 MHz  40 MHz  40 MHz SGI
---  -------  ------  ------  ----------
  0   1          6.5    13.5    15.0
  1   1         13.0    27.0    30.0
  2   1         19.5    40.5    45.0
  3   1         26.0    54.0    60.0
  4   1         39.0    81.0    90.0
  5   1         52.0   108.0   120.0
  6   1         58.5   121.5   135.0
  7   1         65.0   135.0   150.0
  8   2         13.0    27.0    30.0
  9   2         26.0    54.0    60.0
 10   2         39.0    81.0    90.0
 11   2         52.0   108.0   120.0
 12   2         78.0   162.0   180.0
 13   2        104.0   216.0   240.0
 14   2        117.0   243.0   270.0
 15   2        130.0   270.0   300.0

 

(host) # show ap vht-rates bssid 6c:f3:7f:e6:52:f1
AP "Corp-ac" Radio 0 BSSID 6c:f3:7f:e7:51:f0 Very-high-throughput Rates (Mbps)
------------------------------------------------------------------------------
MCS  Streams  20 MHz  20 MHz SGI  40 MHz  40 MHz SGI  80 MHz   80 MHz SGI
---  -------  ------  ----------  ------  ----------  ------   ----------
0    1          6.5     7.2        13.5    15.0        29.3     32.5
1    1         13.0    14.4        27.0    30.0        58.5     65.0
2    1         19.5    21.7        40.5    45.0        87.8     97.5
3    1         26.0    28.9        54.0    60.0       117.0    130.0
4    1         39.0    43.3        81.0    90.0       175.5    195.0
5    1         52.0    57.8       108.0   120.0       234.0    260.0
6    1         58.5    65.0       121.5   135.0       263.3    292.5
7    1         65.0    72.2       135.0   150.0       292.5    325.0
8    1         78.0    86.7       162.0   180.0       351.0    390.0
9    1         --      --         180.0   200.0       390.0    433.3
0    2         13.0    14.4        27.0    30.0        58.5     65.0
1    2         26.0    28.9        54.0    60.0       117.0    130.0
2    2         39.0    43.3        81.0    90.0       175.5    195.0
3    2         52.0    57.8       108.0   120.0       234.0    260.0
4    2         78.0    86.7       162.0   180.0       351.0    390.0
5    2        104.0   115.6       216.0   240.0       468.0    520.0
6    2        117.0   130.0       243.0   270.0       526.5    585.0
7    2        130.0   144.4       270.0   300.0       585.0    650.0
8    2        156.0   173.3       324.0   360.0       702.0    780.0
9    2         --      --         360.0   400.0       780.0    866.7
0    3         19.5    21.7        40.5    45.0        87.8     97.5
1    3         39.0    43.3        81.0    90.0       175.5    195.0
2    3         58.5    65.0       121.5   135.0       263.3    292.5
3    3         78.0    86.7       162.0   180.0       351.0    390.0
4    3        117.0   130.0       243.0   270.0       526.5    585.0
5    3        156.0   173.3       324.0   360.0       702.0    780.0
6    3        175.5   195.0       364.5   405.0        --       --
7    3        195.0   216.7       405.0   450.0       877.5    975.0
8    3        234.0   260.0       486.0   540.0       1053.0   1170.0
9    3        260.0   288.9       540.0   600.0       1170.0   1300.0

 

 


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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