User's Manual

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Fortress ES-Series CLI Guide: Networking and Radio Configuration
62
Mbps
. On a radio using any of the 5 GHz 802.11a settings,
including 802.11na options, the default
MinRate is
6 Mbps
.
3.4.9.5.1 Actual Unicast Transmission Rates
If the Band setting is 802.11a or 802.11g, the fixed unicast
transmission rate you can expect is exactly the
MaxRate you
have entered. However, if the
Band setting is one of the
802.11n options, the fixed unicast transmission rate you can
expect is different depending on certain configuration settings
of the radio on which you are configuring the BSS:
MIMO (see Section 3.4.5),
Force STBC (see Section 3.4.6),
Channel Width (ht20, ht40, ht10; see Section 3.4.2).
When you specify the rate in 802.11n, you are actually
specifying a particular Modulation and Coding Scheme (MCS),
which yields different rates depending on the width of the
channel and the number and use of spatial streams you have
previously specified for the radio.
Example 1: if you pick a fixed
MaxRate of 26, and your radio
has
MIMO enabled and you have not chosen to Force STBC,
you are requesting MCS 11. If your
Band is 802.11n ht40 (40
MHz wide), MCS 11 means the unicast transmission rate for
your BSS will always be 108 Mbps.
Example 2: With everything the same as Example 1 (fixed
MaxRate of 26, MIMO enabled, and Band 802.11n ht40),
enabling
Force STBC will give you MCS 3 and 54 Mbps. The
Force STBC means although you are still using 2 spatial
streams (
MIMO), both are transmitting the same data; Force
STBC
means you are giving up throughput for range and
reliability.
Table 3.8 shows the expected output transmission rates for
each
MaxRate for the combinations of radio configuration.