Cisco Small Business AP541N Administration Manual page 83

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Table 19 Advanced Settings Field Descriptions
Field Description
This field is available only if the radio mode includes 802. 1 1n.
Primary
Channel
This setting can be changed only when the channel
bandwidth is set to 40 MHz. A 40-MHz channel can consist of
two contiguous 20-MHz channels in the same frequency
domain. These two 20-MHz channels are often referred to as
the Primary and Secondary channels. The Primary Channel is
used for 802. 1 1n clients that support only a 20-MHz channel
bandwidth and for legacy clients.
Select one of the following options:
This field is available only if the radio mode includes 802. 1 1n.
Short Guard
Interval
The guard interval is the dead time, in nanoseconds,
Supported
between OFDM symbols. It prevents Inter-Symbol and Inter-
Carrier Interference (ISI, ICI). The 802. 1 1n 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.
Select one of the following options:
• Upper. Set the Primary Channel as the upper 20-MHz
channel in the 40-MHz band.
• Lower. Set the Primary Channel as the lower 20-MHz
channel in the 40-MHz band.
• Yes. The access point transmits data using a 400 ns
guard Interval when communicating with clients that
also support the short guard interval.
• No. The access point transmits data using an 800 ns
guard interval.
Cisco AP541N Dual-band Single-radio Access Point Quick Start Guide
Wireless
Modifying Advanced Settings