Cisco Cisco Aironet 3700i Access Point 백서

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Persistent device avoidance recognizes that certain devices tend to be static in location and frequency, such as

microwave ovens and wireless video cameras. For this reason, even when these devices are not currently
detected on a specific channel at a specific location, it’s known that they are likely to return at locations where they

have been detected previously. The system tracks these kinds of devices and, when channel selection is

performed, tries to avoid channels at locations where persistent devices have been observed.

Furthermore, an access point with Cisco CleanAir technology enabled will share (or propagate) information

regarding the presence of persistent devices it has detected with neighboring Clean Air enabled access points.
In this way, the system helps those access points avoid the possibility of “channel bouncing” (that is, making a

dynamic channel assignment to a channel affected by a persistent interferer).

Cisco CleanAir enabled access points can also share information on avoiding persistent devices with neighboring

access points that do not have CleanAir enabled (assuming that all access points are connected to the same

controller).

Finally, access points in monitor mode (or with the Wireless Security and Spectrum Intelligence [WSSI] module

installed) will also detect and register persistent devices on all the monitored channels. Information on detected

devices is shared with neighboring local mode access points, preventing these access points from using channels

affected by persistent device interference. In this case, Persistent Device Avoidance (PDA) data storage is

extended to keep information about devices on all the channels, and the monitor mode access point is enhanced to

EDRRM recognizes that some interference events are severe and catastrophic in nature. For example, a cordless

phone with a continuous FM signal can cause an outage of several minutes (as long as the phone is active).

For this reason, a dramatic drop in air quality causes the system to immediately evaluate changing the channel for

the affected access point. Note that if a channel change occurs, it is done only for the affected access point, while

avoiding any cascading impact to the channel plan of neighboring access points.

Although in many cases the best response to interference is for the administrator to manually move, remove,

replace, or shield the interfering device, automated mitigation is highly desirable to maintain short-term

performance until other actions can be taken. And in certain cases, it may not be possible to remove the source of

interference - for example, if it comes from outside the building.

Extensibility to New Technologies

The fundamental features and benefits provided by Cisco CleanAir technology are directly extensible to emerging

Wi-

Fi technologies. CleanAir 80 MHz is a new capability for Cisco’s proven and unrivaled CleanAir functionality to

cover a full 80-

MHz channel width in support of 802.11ac networks. This solution continues to extend Cisco’s

patented RF interference detection, location, and mitigation via optimization for the wider channel width enabled by

802.11ac.

For example, when the 802.11ac module is installed and enabled in a Cisco Aironet 3600 Series Access Point, the

CleanAir subsystem will monitor the entire 80-MHz channel (that is, the 5-GHz 802.11n radio native to the Aironet

3600 Series monitors the full channel bandwidth being used by the 802.11ac module instead of monitoring only its

own 40-MHz-wide channel).

Furthermore, this same proven functionality is provided in the new Cisco Aironet 2700 and 3700 Series access

points. As with the Aironet 3600 Series plus the 802.11ac module, the CleanAir subsystem within the Aironet 2700

and 3700 Series will report interferers detected within the full 80-MHz channel in addition to creating AQ reports for

each of the four 20-MHz channels that form the 80-MHz channel.