Users Guide

610 | Spectrum Analysis Dell PowerConnect W-Series ArubaOS 6.1 | User Guide
requested. Each client may select up to eight different spectrum analysis charts and graphs to appear in the
spectrum dashboard.
A controller can support up to 22 active WebUI connections. If spectrum analysis clients are simultaneously
viewing WebUI data for than 22 spectrum analysis devices, any additional WebUI requests will be refused until
some clients close their WebUI browser sessions.
When you finish reviewing data from an SM or hybrid AP, you should disconnect the device from your spectrum
client. Do not forget this important step—no other user will be able to access data from that spectrum monitor or
hybrid AP until you release your subscription. Note, however, that when you disconnect a spectrum monitor from
your client, the AP will continue to operate as a spectrum monitor until you return it to AP mode by removing
the local spectrum override, or by changing the mode parameter in the AP’s 802.11a or 802.11g radio profile from
spectrum-mode back to AP-mode.
When a spectrum monitor or hybrid AP is not subscribed to any client, it will still perform all classification tasks
and collect all necessary channel lists and device information. You can view classification, device and channel
information for any active spectrum monitor or hybrid AP via the controller's command-line interface, regardless
of whether or not that device is sending real-time spectrum data to another client WebUI.
Individual spectrum analysis graphs and charts are explained in detail in “Customizing Spectrum Analysis
Graphs” on page621.
Hybrid AP Channel Changes
By default, a hybrid AP only monitors the channel specified in its 802.11a or 802.11g radio profile for spectrum
interference. If you want to change the channel monitored by a hybrid AP, you must edit the channel setting in
those profiles. There are, however, other ArubaOS features that may automatically change the channels on hybrid
APs. APs using Dynamic Frequency Selection (DFS) perform off-channel scanning to detect the presence of
satellite and radar transmissions, and switch to a different channel if it detects that satellite or radar transmissions
are present. APs using the Adaptive Radio Response (ARM) feature constantly monitor the network and
automatically select the best channel and transmission power settings for that AP. If you manually change a
channel monitored by a hybrid AP, best practices are to temporarily disable the ARM feature, as ARM may
automatically return the channel to its previous setting.
If a hybrid AP is using ARM or DFS, that hybrid AP may automatically move to a different channel in response to
changes in the network environment. If a hybrid AP changes channels while it is connected to a spectrum analysis
client, the hybrid AP will update the graphs in the spectrum dashboard to start displaying spectrum data for the
new channel, and will send a log message to the a spectrum analysis log. For details on changing the channel
monitored by a hybrid AP, see “802.11a/802.11g RF Management Configuration Parameters” on page233.
Hybrid APs Using Mode-Aware ARM
If a radio is configured as a hybrid AP and that AP is enabled with mode-aware ARM, the hybrid AP can change to
an Air Monitor (or AM) if too many APs are detected in the area. If the ARM feature changes a hybrid AP to an
Air Monitor, that AM will not provide spectrum data after the mode change. The AM will unsubscribe from any
connected spectrum analysis client, send a log message warning about the change. If mode-aware ARM changes
the AM back to an AP, the hybrid AP will not automatically resubscribe back to the spectrum analysis client. The
hybrid AP must manually resubscribed before it can appear in the client’s spectrum monitors page.
NOTE: A spectrum monitor or hybrid AP automatically disconnects from a client when you close the browser window you used to
connect the spectrum monitor to your client. However, if you are using Internet Explorer and have multiple instances of an
Internet Explorer browser open, the data-streaming connection to the spectrum monitor or hybrid AP will not be released until 60
seconds after you close the spectrum client browser window. During this 60-second period, the user will see the spectrum
monitor is still being connected to the client.