Controller Based WLANs

How does the client locate function and triangulation work?

Aruba Employee

Product and Software: This article applies to all Aruba controllers and ArubaOS 3.x and later.

The air monitoring (AM) process on all Aruba APs continuously monitors the RF spectrum for wireless devices (APs and clients). This monitoring happens whether or not the AP is a "valid" AP (that is, part of the controller) or the client is associated to one of the Aruba APs on this controller. When a wireless device is detected, the details of the clients including the signal-to-noise ratio (SNR) are sent to the master controller or to the management platform (AirWave) if wireless management system (WMS) off-load is enabled. This information is stored in the WMS database.

When a network administrator attempts to "Locate" a client in RFPlan on the controller WebUI or in VisualRF on AirWave, the WMS database is searched. If at least three recent entries for the MAC address of this wireless device (client or AP) have been reported by three different sources (APs), the location of the device will be reported, based on the SNR as reported by these APs.

To troubleshoot this issue, ensure that enough APs are in use to supply the signal strength information for a wireless device. Three reporting APs is the minimum. The primary function of an AP is to serve wireless clients, so it spends most of the time on one channel. An AP will go off-channel regularly to scan for wireless device. For an AP to detect wireless devices on a different channel, the wireless device must be transmitting when the AP is listening on the channel where the wireless device is transmitting. RF monitoring is less effective if the monitoring AP is actively serving a client. Therefore, to approve the accuracy of client location functionality, the use of dedicated AM is recommended.

To check the WLAN device SNR which is reported by the AP/AM on the controller, issue the following command:

#show ap monitor ap-list ap-name <Name of detecting AP>

Example

(rn-pilot-hk) #show ap monitor ap-list ap-name hk-rap-ap65

Monitored AP Table
------------------
bssid essid chan ap-type phy-type dos mt it load-balance nstas avg-rssi curr-rssi wired-macs
----- ----- ---- ------- -------- --- -- -- ------------ ----- -------- --------- ----------
00:0b:86:53:15:c8 rn-pilot-hk 40 valid 80211a disable 1167081 0 disable 0 60 60 15
00:0b:86:53:15:ca Guest 40 valid 80211a disable 1167081 0 disable 0 60 60 1
00:0b:86:53:15:cb Family-a 40 valid 80211a disable 1167081 0 disable 0 60 60 0
00:0b:86:53:15:c2 Guest 1 valid 80211b/g disable 1166916 0 disable 0 60 60 1
00:0b:86:53:15:cc phome 40 valid 80211a disable 1167081 0 disable 0 60 60 0
00:0b:86:53:15:c1 Family 1 valid 80211b/g disable 1166916 0 disable 0 60 60 0
00:0b:86:53:15:c3 phome 1 valid 80211b/g disable 1166916 0 disable 0 60 60 0
00:0b:86:53:15:c9 Family 40 valid 80211a disable 1167081 0 disable 0 60 60 1
00:0b:86:53:15:c0 rn-pilot-hk 1 valid 80211b/g disable 1166914 0 disable 0 60 60 15
00:25:12:69:9f:91 pccw2009 2 interfering 80211b/g disable 5186 0 disable 1 0 16 0
36:23:7d:ac:8d:db hpsetup 6 interfering 80211b disable 2357 0 disable 0 0 8 0
00:16:01:2d:8c:18 tomhome 2 interfering 80211b/g disable 769 0 disable 0 0 14 0
00:14:d1:44:39:86 TRENDnet 6 interfering 80211b/g disable 1080 1 disable 0 0 18 0
00:1d:0f:d0:04:2e tuna 7 interfering 80211b/g disable 227 1 disable 0 0 26 0
00:25:86:d0:10:60 099 6 interfering 80211b/g disable 1080 3 disable 0 0 12 0
00:14:78:b9:6c:6e Jason and LXD 6 interfering 80211b/g disable 1080 0 disable 0 0 21 0
00:1c:df:05:b1:10 Au_N1 6 interfering 80211b/g-HT-40 disable 1080 0 disable 0 0 20 0
00:22:6b:df:6b:e6 kezhk 6 interfering 80211b/g disable 1080 0 disable 0 0 16 0
00:23:cd:d7:8e:18 happyic 6 interfering 80211b/g disable 1080 1 disable 0 0 13 0
00:40:05:5a:76:b7 default 6 interfering 80211b disable 1080 4 disable 0 0 16 0
00:25:86:bd:a0:7c wowwow 6 interfering 80211b/g-HT-40 disable 1080 0 disable 0 0 15 0
00:18:39:82:f2:ef Turboturd 6 interfering 80211b/g disable 1079 0 disable 0 0 12 0
00:e0:fc:12:8e:0b HSPAWirelessGateway00e0fc128e0b 8 interfering 80211b/g disable 227 0 disable 0 0 14 0
00:24:01:b8:a8:ab sunying 6 interfering 80211b/g disable 833 0 disable 0 0 8 0
00:22:93:28:8f:69 9 interfering 80211b/g disable 226 0 disable 0 0 14 0
00:1c:df:17:4b:f2 SIL 11 interfering 80211b/g disable 4559 0 disable 1 0 8 2
00:1e:73:b6:b6:18 9 interfering 80211b/g disable 221 0 disable 0 0 13 0
00:1e:73:b6:b6:16 FELIX 9 interfering 80211b/g disable 221 0 disable 0 0 13 0
00:15:eb:4d:86:ed wongsochun8 3 interfering 80211b/g disable 217 6 disable 0 0 16 0
00:25:12:69:9f:93 2 interfering 80211b/g disable 207 1 disable 0 0 17 0
00:22:93:28:8f:67 Default 9 interfering 80211b/g disable 152 4 disable 0 0 16 0
00:1a:70:d3:0a:f9 HK HOME 1 interfering 80211b/g-HT-40 disable 17013 0 disable 0 8 10 4
00:1b:2f:f5:4f:c4 DUCKDUCKNETGEAR 11 interfering 80211b/g disable 1339 0 disable 0 0 5 0
00:0d:0b:5e:7f:f8 000D0B5E7FF8 11 interfering 80211b/g disable 1117 5 disable 0 0 9 0
00:0f:a3:58:c8:5d LSTLKKC 6 interfering 80211b/g disable 127 0 disable 0 0 15 1
00:1f:c6:75:4a:b2 Family_CHEN 11 interfering 80211b/g disable 120 1 disable 0 0 15 0
00:1b:63:24:22:11 JB 10 interfering 80211b/g disable 113 5 disable 0 0 6 0
00:01:38:db:da:c1 Nvidia_PCCW09 1 interfering 80211b/g-HT-40 disable 14834 0 disable 0 10 11 1
00:01:38:db:da:c0 1 interfering 80211b/g-HT-40 disable 14390 0 disable 0 10 11 1
00:0f:a3:58:cb:56 LSTLKKC 2 interfering 80211b/g disable 98 0 disable 0 0 6 2
00:1e:e5:90:30:68 linksys 6 interfering 80211b/g disable 81 0 disable 0 0 15 0
00:24:82:22:cf:78 ONE PACIFIC HEIGHTS 6 interfering 80211b/g disable 68 0 disable 0 0 15 0
00:23:f8:08:15:02 6 interfering 80211b disable 68 1 disable 0 0 8 0
00:17:9a:2d:e0:6a BrokenWireless 1 interfering 80211b/g-HT-40 disable 7580 0 disable 0 9 10 0
00:19:cb:4e:80:ec blanc 6 interfering 80211b/g disable 51 1 disable 0 0 5 0
00:25:12:69:9f:94 2 interfering 80211b/g disable 45 1 disable 0 0 17 0
00:11:6b:1e:60:14 WBR-3408 11 interfering 80211b/g disable 43 1 disable 0 0 6 0
00:1c:10:56:1c:07 1PDCYDH5VQ 11 interfering 80211b/g disable 41 7 disable 0 0 1 0
00:0f:a3:58:ca:53 LSTLKKC 10 interfering 80211b/g disable 39 2 disable 0 0 6 1

Version history
Revision #:
1 of 1
Last update:
‎07-05-2014 03:51 AM
Updated by:
 
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