HP MSM3xx Management And Configuration Manual page 62

Wireless configuration
Radio configuration
The AP does not use protection mechanisms (RTS/CTS or CTS-to-self) when operating in
this mode, which provides for the best throughput tor the AP and its 802.11n clients.
However, if legacy clients are using the same channel, this can lead to collisions and
potentially serious performance deterioration for all traffic (802.11n and legacy a/b/g) on
the channel.
The AP will still signal associated clients to use protection when they send data. The AP
does this via a field in the beacons that it sends. So clients sending data to the AP will use
protection, but data sent from the AP will not be protected.
Note
This mode is sometimes incorrectly called Greenfield. Greenfield is an 802.11n-specific
preamble that can be used by clients and APs. HP APs do not support this preamble and
therefore do not support Greenfield mode.
When to use this mode
Use this mode when the AP is installed in an area where there is no legacy wireless traffic
on the channel that the AP will use, and all potential wireless client devices support
802.11n.
802.11n/a
Supported on
Frequency band
Data rates
HP refers to this mode as Compatibility mode because the AP allows both 802.11n and
legacy clients to associate. The AP advertises protection in the beacon when legacy
clients are associated or operating on the same channel. This alerts associated 802.11n
clients to use protection when transmitting. The AP also uses protection mechanisms
(RTS/CTS or CTS-to-self) when sending 802.11n data to prevent disruption to legacy
clients associated on the same channel.
802.11n/g
Supported on
Frequency band
Data rates
This mode is the same as 802.11n/b/g except that 802.11b clients are prevented from
associating. The AP does not advertise 1, 2, 5.5 and 11 Mbps as supported rates in its
beacons or Probe-Responses. The AP does not tell 802.11g clients to use protection, and
3-20
MSM410, MSM422 (radio 1)
5 GHz
For 802.11n clients: Up to 300 Mbps.
For 802.11a clients: Up to 54 Mbps.
MSM410, MSM422 (radio 1)
2.4 GHz
For 802.11n clients: Up to 130 Mbps. (Up to 300 Mbps
when using a 40 MHz channel width, which is not
recommended in the 2.4 GHz frequency band.)
For 802.11g clients: Up to 54 Mbps.