User guide

Radio and Antenna Configuration
Enterasys Wireless Standalone 802.11n AP User Guide 4-25
11b Settings (Radio 2 only)
Preamble Select a preamble for 11b-specific (CCK) rates: Short or Long.
•Select Short if compatibility with early 11b clients is not
required.
•Select Long (default) if compatibility with early 11b clients is
required.
To avoid problems with wireless communication, all APs, network
adapters, and other wireless devices should use the same
preamble. High network traffic areas should use a Short
preamble.
11g Settings (Radio 2 only)
Protection Mode Select a protection mode: None, Auto, or Always. The default
and recommended setting is Auto. Click None if 11b APs and
clients are not expected. Click Always if you expect many 11b-
only clients.
Note: The overall throughput is reduced when Protection Mode
is enabled, due to the additional overhead caused by the RTS/
CTS. The overhead is minimized by setting Protection Type to
CTS-to-Self and Protection Rate to 11 Mbps. The overhead
causes the overall throughput to be sometimes lower than if just
11b mode is used. If there are many 11b clients, it is
recommended to disable 11g support (11g clients are backward
compatible with 11b APs).
An alternate approach, although potentially a more expensive
method, is to dedicate all APs on a channel for 11b (for example,
disable 11g on these APs) and disable 11b on all other APs. The
difficulty with this method is that the number of APs must be
increased to ensure coverage separately for 11b and 11g clients.
Protection Rate Select a protection rate: 1, 2, 5.5, or 11 Mbps. The default and
recommended setting is 11. Only reduce the rate if there are many
11b clients in the environment or if the deployment has areas with
poor coverage. For example, rates lower than 11 Mbps are
required to ensure coverage.
Protection Type Select a protection type: CTS-to-Self or RTS-CTS. The default
and recommended setting is CTS-to-Self. Select RTS-CTS only if
an 11b
AP that operates on the same channel is detected in the
neighborhood, or if there are many 11b-only clients in the
environment.
11n Settings
Protection Mode Enable or disable protection mode. This protects high throughput
transmissions on primary channels from non-11n
APs and clients.
Click Disabled if non-11n APs and clients are not expected. Click
Enabled if you expect many non-11n
APs and clients. The overall
throughput is reduced when Protection Mode is enabled. The
protection mode is enabled by default.
40MHz Protection Mode Select a 40MHz protection type, CTS-to-Self or RTS- CTS, or
None. This protects high throughput transmissions on extension
channels from interference from non-11n APs and clients when a
40MHz channel is used. The default is CTS-to-Self.
Field Description