Cisco Cisco WAP351 Wireless-N Dual Radio Access Point with 5-Port Switch 관리 매뉴얼

다운로드
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Wireless
Radio
Cisco WAP131 and WAP351 Administration Guide
76
5
referred to as the primary and secondary channels. The primary channel is 
used for 802.11n clients that support only a 20-MHz channel bandwidth and 
for legacy clients.
Choose one of these options:
-
Upper—Sets the primary channel as the upper 20-MHz channel in the 
40-MHz band.
-
Lower—Sets the primary channel as the lower 20-MHz channel in the 
40-MHz band. Lower is the default selection.
Channel—The portion of the radio spectrum that the radio uses for 
transmitting and receiving.
The range of available channels is determined by the mode of the radio 
interface and the country code setting. If you select Auto for the channel 
setting, the WAP device scans available channels and selects a channel 
where the least amount of traffic is detected.
Each mode offers a number of channels, depending on how the spectrum is 
licensed by national and transnational authorities such as the Federal 
Communications Commission (FCC) or the International Telecommunication 
Union (ITU-R).
STEP  5
In the Advanced Settings area, configure these parameters:
Short Guard Interval Supported—This field is available only if the selected 
radio mode includes 802.11n. The guard interval is the dead time, in 
nanoseconds, between OFDM symbols. The guard interval prevents Inter-
Symbol and Inter-Carrier Interference (ISI, ICI). The 802.11n mode allows for 
a reduction in this guard interval from the a and g definition of 800 
nanoseconds to 400 nanoseconds. Reducing the guard interval can yield a 
10 percent improvement in data throughput. The client with which the WAP 
device is communicating must also support the short guard interval. 
Choose one of these options:
-
Yes—The WAP device transmits data using a 400-nanosecond guard 
interval when communicating with clients that also support the short 
guard interval. This is the default selection.
-
No—The WAP device transmits data using an 800-nanosecond guard 
interval.