Wireless
Modifying Advanced Settings
78
Cisco AP541N Dual-band Single-radio Access Point Quick Start Guide
4
Primary
Channel
This field is available only if the radio mode includes 802.11n.
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 802.11n clients that support only a 20-MHz channel
bandwidth and for legacy clients.
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.
Short Guard
Interval
Supported
This field is available only if the radio mode includes 802.11n.
The guard interval is the dead time, in nanoseconds,
between OFDM symbols. It 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.
Select one of the following options:
•
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.
Table 19
Advanced Settings Field Descriptions
Field
Description
