H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 740)

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When the AP operates in monitor mode or hybrid mode, it can locate wireless clients or other
wireless devices that are not associated with it. H3C does not recommend this mode because
frequent channel change might affect Tag locating performance.
NOTE:
•
For more information about monitor mode and hybrid mode, see " Configuring WLAN security ."
• An AP operates in normal mode when it functions as a WLAN access point. For more information, see
"
Configuring access services ."
After the processes, the AP begins to collect Tag and MU messages.
Upon receiving Tag messages (assume that the Tags mode has been configured on the AC, and
the location server has notified the AP to report Tag messages), the AP checks the Tag messages,
encapsulates those passing the check, and reports them to the location server. The AP
encapsulates Tag messages by copying all the information (including the message header and
payload) except the multicast address, and adding the BSSID, channel, timestamp, data rate,
RSSI, SNR, and radio mode of the radio on which the relevant Tag messages were received.
Upon receiving MU messages (assume that the MUs mode has been configured on the AC, and
the location server has notified the AP to report MU messages), the AP checks the messages,
encapsulates those that pass the check, and reports the messages to the location server. The AP
encapsulates an MU message by copying its source address, Frame Control field, and
Sequence Control field, and adding the BSSID, channel, timestamp, data rate, RSSI, SNR, and
radio mode of the radio on which the relevant Tag messages were received.
3. Calculate the locations of Tags or MUs:
After receiving Tag and MU messages from APs, the location server uses an algorithm to calculate
the locations of the Tag and MU devices according to the RSSI, SNR, radio mode, and data rate
carried in the messages, and displays the locations on the imported map. Typically, a location
server can calculate the locations if more than 3 APs report Tag or MU messages.
Wireless location protocols
An AP supports the following wireless location protocols:
• AeroScout protocol—A protocol made by AeroScout for communications between location servers
and APs. It supports both dynamic and static wireless location methods.
• General wireless location protocol—A protocol made by H3C for communications between
location servers and APs. It supports only the static wireless location method.
Wireless location rate limiting
The AeroScout protocol uses the dilution feature to reduce the MU messages when a WLAN is busy.
However, when the network is not busy, the dilution feature might cause location failures that result from
MU message loss.
To resolve this problem, you can configure wireless location rate limiting to prevent excessive MU
messages from affecting the operation of the network and location server.
• AP-based rate limiting—Rate limits the MU messages from all APs.
• Client-based rate limiting—Rate limits the MU messages for each client.
CUPID location
Capturing User Positioning Including Direct path (CUPID) location can precisely locate multiple clients. It
is more immune to interferences, multipath effect, deployment density, and environment changes than
other location methods.