Cisco 2700 Series Wireless Location ApplianceDeployment GuideThis document provides configuration and deployment guidelines as well as troubleshooting tips andanswers to frequently asked technical questions for those adding the Cisco 2700 Series WirelessLocation Appliance (hereafter referred to as the location appliance) (Figure 1) to a Cisco wireless LANnetwork. The existing installation and configuration guides for this appliance are available at thefollowing 6/tsd products support series home.htmlNoteThis document assumes an indoor installation of the location appliance, and any guidelines andaccuracies cited are consistent with that assumption.Figure 1Cisco 2700 Location ApplianceThe location appliance tracks 802.11 devices directly from a wireless LAN infrastructure usingadvanced RF fingerprinting technology. Additionally, the appliance records information so that you canestablish location trends and resolve problems regarding RF capacity.By design, the location appliance is directly integrated into the wireless LAN infrastructure and isconfigured through its command-line interface and then managed through WCS. The location appliancetracks the physical location of wireless devices using wireless LAN controllers and Cisco AironetCorporate Headquarters:Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA 95134-1706 USA 2005 Cisco Systems, Inc. All rights reserved.
lightweight access points. This appliance tracks any Wi-Fi device, including Wi-Fi clients,standards-based Wi-Fi active RFID tags, rogue access points, and clients. It was designed with thefollowing requirements in mind: Manageability—The same browser-based interface that is used for the Cisco WCS is also used forthe appliance. Moreover, the location appliance integrates directly into the wireless LANarchitecture, providing one unified network to manage instead of multiple disparate wirelessnetworks. Scalability —The appliance was built to simultaneously track up to 1500 wireless devices. WCS canmanage multiple location appliances for greater scalability. Security—The controller, WCS, and the location appliance were separated to deliver the most securearchitecture possible. The appliance records historical location information that can be used foraudit trails and regulatory compliance. Open and standards based—The appliance has a SOAP/XML API that can be integrated by partnerswith other business applications and can track any standards. Easy deployment of business applications—The appliance can be integrated with new businessapplications such as asset tracking, inventory management, location-based security, or automatedworkflow management.Location TrackingThe location appliance calculates the location of tracked devices using RF fingerprinting. This techniqueuses RF characteristics such as reflection, attenuation, and multi-path to impact signal strength readingsof devices in specific environments.To detect the RF signal at each location in an enterprise, the system must first understand how the RFinteracts with an installation's environmental variables, such as building materials, walls, doors, andfurniture. As such, an RF calibration is required (post wireless LAN installation) to determine thecharacteristics of that specific RF environment.When an RF calibration is performed, the attenuation of walls and other building characteristics is takeninto account. The extent of RF reflection and multi-path is also calculated for every coordinate, or grid,on a floor map in the management system for each access point. For a single point on the grid, manydifferent access points detect devices; however, each access point detects these devices at different signalstrengths.At the conclusion of calibration, a database is populated inside of the management system. That databasecontains each coordinate and how each access point views that coordinate from the standpoint of signalstrength.When devices' locations are requested by the management system, each controller replies on behalf ofits access points with the signal strengths at which they detect them. The management system thenmatches the information it gathers from the controllers against its database of location RF fingerprints.Devices' locations are then plotted visually on a floor map.Performing a CalibrationYou can generate the location of coordinates of tracked devices by using prediction. The locationcoordinates generated in this case are predicated from RF models that the engine already has in itsknowledge base. However, if the location resolution is not within specifications, it can be further tunedusing a technique known as calibration.Cisco 2700 Series Wireless Location Appliance Deployment Guide2OL-8478-01
Calibration is the process whereby sample signal strength measurements are physically taken in theactual environments in which you wish to perform location tracking as inputs to tune the locationtracking rather than using the canned or simulated environment’s inputs. Calibration is performed on aper-floor basis with a wireless laptop using RSSI measurements.The goal of the calibration process is to refine location accuracy to be within the specifications (10 m,90%). The calibration is done by taking site specific measurements into account and narrowing the deltabetween the actual and the predicted location coordinates of a tracked device. The calibration process iscomplete when the actual and predicted location coordinates converge. On a per-floor basis, a wirelesslaptop takes RSSI measurements. The calibration wizard, embedded in the WCS version of the product,is launched from the laptop and guides the user through the calibration process.AccuracyBecause location fidelity is statistical, the location coordinates can be either more or less accurate than10 meters the other 10% of the time. The location coordinates that fall into this other 10% are known asoutliers. Making adjustments to the deployments of access points to provide more optimal placement, inaddition to performing a calibration, can sometimes yield more accurate results; however, the results arevery dependent on environment and deployment.Software RequirementsAccess points and controllers must be installed with a version of WCS using embedded location.Table 1WCS VersionsPart NumberDescriptionAIR-LOC-2700-L-K9Cisco wireless location appliancesAIR-WCS-LL-1.0-K9Cisco WCS with location v1.0 with up to 50Cisco Aironet 1000 series access points running LinuxAIR-WCS-WL-1.0-K9Cisco WCS with location v1.0 with up to 50 Cisco Aironet 1000series access points running Windows 2000/2003 serverExpansion licenses are available if greater scale is necessary. Visit the following location for more s/4.1/configuration/guide/wcswarr.htmlHardware RequirementsBecause the location appliance participates in a Lightweight Access Point Protocols (LWAPP)architecture, this guide assumes the user already has or is in process of putting an LWAPP- capablewireless LAN in place. Both an explanation of the various LWAPP components you can use to dolocation tracking as well as a hardware compatibility matrix is provided to ensure all requiredLWAPP-compatible infrastructure is in place to support location tracking.Cisco 2700 Series Wireless Location Appliance Deployment GuideOL-8478-013
The following Cisco wireless LAN controllers are available.Table 2ControllersPart NumberDescriptionAIR-WL C2006-K9Cisco 2000 series wireless LAN controller for up to six CiscoAironet 1000 series lightweight access pointsAIR-WL C4402-12-K94400 series WLAN controller for up to 12 Cisco Aironet 1000series access pointsAIR-WL C4402-25-K94400 series WLAN controller for up to 25 Cisco Aironet 1000series access pointsAIR-WL C4402-50-K94400 series WLAN controller for up to 50 Cisco Aironet 1000series access pointsAIR-WL C4404-100-K94400 series WLAN controller for up to 100 Cisco Aironet 1000series access pointsThe following Cisco Aironet access points are available.Table 3Access PointsPart NumberDescriptionAIR-AP1010-X-K91000 series 802.11 a/b/g access point with integrated antennas,x regulatory domainAIR-AP1020-X-K91000 series 802.11 a/b/g access point with integrated antennaand RP-TNC, x regulatory domainAIR-AP1030-X-K91000 series 802.11 a/b/g remote edge access point withintegrated antenna and RP-TNC, x regulatory domainAIR-LAP1131AG-x-K9802.11 a/g Non-modular LWAPP AP: Integrated AntennasAIR-LAP1232AG-x-K9AIR-AP1210 platform with AIR-MP21G and AIR-RM22Aradio modulesAIR-LAP1242AG-x-K9802.11 a/g Non-modular LWAPP APThe Difference Between WCS with Location and the Location ApplianceWCS without the use of the location appliance supports on-demand or query-based location. Thisversion visually displays a single device's location at a time, placing each single device on the floor mapassociated with the floor it is on. Location determination using this version of WCS with location iscaptured in Figure 2 where the blue icon is the only visual presented of a Wi-Fi client device.Cisco 2700 Series Wireless Location Appliance Deployment Guide4OL-8478-01
Figure 2NoteLocation DeterminationTo add the location appliance, the WCS version with location must be installed. You cannot add thelocation appliance to the WCS base version.Additional Functionality with Location ApplianceFigure 3 illustrates the scale and variety of classes of devices that can be tracked by the locationappliance. You can narrow the search parameters if you are interested only in a subset of devices. Forexample, a biomedical user may want to see only infusion pumps and EKG machines named withfriendly identifiers rather than rogue devices or devices with cryptic MAC or IP addresses.Cisco 2700 Series Wireless Location Appliance Deployment GuideOL-8478-015
System ArchitectureFigure 3Scale and Variety of DevicesSystem ArchitectureThe location appliance integrates with Cisco's centralized wireless LAN architecture. The appliance sitsout of the data path of the wireless LAN, working with both the WCS and the controllers to track devicelocations (see Figure 4).Cisco 2700 Series Wireless Location Appliance Deployment Guide6OL-8478-01
Location-Based Services OverviewFigure 4System ArchitectureAccess points can detect devices both on the channels where they service clients and on all otherchannels by periodically scanning, while still providing uninterrupted data access to their wirelessclients. The gathered raw location data is then forwarded from each access point upstream to itscontroller. The location appliance polls controllers via SNMP for this raw location information.To understand this gathered device information, the location appliance works with WCS to determineaccess point and device locations, based on input network diagrams that consist of floor maps. The visualfront-end of the location appliance is provided through WCS where either a single device's location oran entire floor's devices may be depicted simultaneously. All device details and specific historicallocation information is accessed through WCS as well.Location-Based Services OverviewUsing Cisco's Centralized wireless LAN architecture and location-based services, administrators candetermine the location of any 802.11-based device, as well as the specific type of each device. Clients,rogue access points, rogue clients, and asset tags can all be identified and located by the system.Clients are all devices associated with controller-based, lightweight access points on your network.Rogue access point is any access point that is determined not to be part of the wireless LAN that detectedit. This consists of all non-system access points within earshot of lightweight access points, includingthose on the wired network or those on another wired network (such as a neighbor's access point).Because all lightweight access points hash a portion of the beacon frame with a special key, even spoofedinfrastructure access points are identified as rogue access points, rather than mistakenly indicated to belegitimate access points flagged in WCS as spoof access points.Cisco 2700 Series Wireless Location Appliance Deployment GuideOL-8478-017
Deployment and Design RequirementsRogue clients are simply all client devices that are associated to rogue access points.Asset tags are any vendors' 802.11-based RF ID tags within range of infrastructure access points.Deployment and Design RequirementsConsider the type of devices involved and how many devices will be tracked. Tracking of any of the fourdevice types can be configured. Determine the total number of devices and plan to deploy one locationappliance for every 1500 simultaneously tracked devices.Depending on network requirements, placement of the location appliance in relation to WCS can beadjusted to fit specific site needs. Where a single WCS is used for wireless LAN management, one ormore location appliances can be used to track 1500 or more devices. When multiple WCS are used tomanage separate wireless LANs, a single location appliance can be used by all WCSs to track eachdevice if the total number of tracked devices among them all does not exceed 1500.NoteIf WCS and controllers are not physically co-located or have fast connections between them, deploy thelocation appliance(s) as close as possible to WCS. Network diagrams (floor plan maps and the accesspoint locations on those maps) are synchronized between both devices.Designing the Wireless LAN for LocationThe Cisco Aironet 1000 series access points are supported by the Wireless LAN Controllers (2000-,4100, and 4400-series controllers as well as Cisco Catalyst 6500 Series Wireless Services Module(WiSM) which forward device information up to the location appliance. Antenna configuration on theseaccess points is important. The internal antenna of the Cisco Aironet 1000 series access point allows fordevice location tracking, as do external antennas supported on both those acc