Cisco Cisco Catalyst 6000 Multilayer Switch Feature Card MSFC2 White Paper
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will be sent. The highest mandatory rate is the speed at which multicast will be broadcast. The design for a
high-density WLAN should use a minimum mandatory data rate of 18 or 24 Mbps.
Wireless=>802.11a/802.11b=>RRM
RRM should be used to manage both power and channel within a high-density WLAN. This will ensure that power
levels and channel selection are optimized. RRM will monitor the OTA propagation and utilization metrics and
adjust all APs based on their view of one another for optimal bandwidth/performance. Refer to the WLC
Configuration Guide for a complete discussion regarding configuration.
Specific recommendations for high-density WLAN deployments include:
Transmit Power Control Algorithm (TPC)
●
Min/Max power sets a limit on the minimum and maximum power that a radio can use. It overrides TPC
recommendations and effects only the local controller and associated APs.
●
TPC power threshold is used to adjust the power at the edge of the cell. The default is -70 dBm. Tune for
specific installation requirements. It may be necessary to adjust the TPC power threshold in an
environment with a ceiling over 25 feet high.
Dynamic Channel Assignment (DCA) Algorithm
●
Defaults should suffice with the following exceptions:
◦
Avoid foreign AP interference. This tells the DCA to accommodate channels in use by a foreign AP and
to attempt to work around that assignment. If on the border with another coverage zone under a
separate RF group, enable this (default). Disable this if there are other networks operating that are
outside of your control.
◦
DCA channel sensitivity (medium is the default) should work fine in most applications. Set to low to
make a channel change highly unlikely. Set to high to encourage channel changes in response to
environmental changes.
◦
In 802.11a only environments with a channel width of 20 MHz/40 MHz, most high-density environments
will benefit more from more available channels. But certain applications, such as video, will utilize 40
MHz effectively.
◦
DCA channels 100-140 and 165 disabled by default enable extended UNII-2 channels to select 100-140
automatically.
Coverage Hole Detection Algorithm
●
Coverage threshold: Data RSSI should be set for the minimum acceptable RSSI level to support the
minimum data rate required in the high-density coverage area. This will allow Coverage Hole to report
instances where a client exceeded that threshold.
Note:
Default values should be sufficient for client exception levels. Enabling a realistic threshold will allow the
system to track and report clients by MAC address that fall below the threshold. If location services are available,
this can be plotted on the map display. This can be very useful in troubleshooting the final deployment or to
identify a new client type that has different RF capabilities.