H3C WA2612-AGN Web-Based Configuration Manual page 189

Item
802.11n
Bandwidth Mode
Auto-switch
Client 802.11n Only
A-MSDU
A-MPDU
Short GI
Description
IMPORTANT:
The option is available only when the AP supports 802.11n and the radio mode
is 802.11n.
802.11n can bond two adjacent 20-MHz channels together to form a
40-MHz channel. During data forwarding, the two 20-MHz channels can
work separately with one acting as the primary channel and the other acting
as the secondary channel or work together as a 40-MHz channel. This
provides a simple way of doubling the data rate.
By default, the channel bandwidth of the 802.11n radio (5 GHz) is 40 MHz,
and that of the 802.11n radio (2.4 GHz) is 20 MHz.
IMPORTANT:
•
If the channel bandwidth of the radio is set to 40 MHz, a 40 MHz channel
is used as the working channel. If no 40 MHz channel is available, a 20
MHz channel is used. For the specifications, see IEEE P802.1 1n D2.00.
•
If you modify the bandwidth mode configuration, the transmit power is
automatically refreshed.
If select the Auto-switch box, the bandwidth mode of a radio can be switched.
When an 802.11gn radio operates in 40 MHz bandwidth mode, the
auto-switch is not enabled by default.
This function is supported only when 802.11n radios operate in 2.4 GHz.
If you select the Client 802.11n Only box, non-802.11n clients are prohibited
from access. If you want to provide access for all 802.11a/b/g clients, you
must disable this function.
IMPORTANT:
To allow only 802.11n clients to access the network, you must configure
mandatory MCS. For the configuration of mandatory MCS, see
802.11n rates."
Select A-MSDU to enable A-MSDU.
Multiple MAC Service Data Units (MSDU) can be aggregated into a single
A-MSDU. This reduces the MAC header overhead and improves MAC layer
forwarding efficiency.
IMPORTANT:
If 802.11n radios are used in WDS, make sure that the A-MSDU configuration of
each AP is the same.
Select A-MPDU to enable A-MPDU.
802.11n introduces the A-MPDU frame format. By using only one PHY header,
each A-MPDU can accommodate multiple Message Protocol Data Units
(MPDUs) which have their PHY headers removed. This reduces the overhead in
transmission and the number of ACK frames to be used, and improves network
throughput.
Select Short GI to enable short GI.
Delays may occur during receiving radio signals due to factors like multi-path
reception. Therefore, a subsequently sent frame may interfere with a
previously sent frame. The GI function is used to avoid such interference.
The short GI function is independent of bandwidth and supports both 20MHz
and 40MHz bandwidths.
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"Configuring