Cisco 3300 Series Mobility Services Engine

Document ID: 107571

Contents

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
Background Information
Received Signal Strength Indication
Time Difference of Arrival
System Architecture
Hardware Requirements
Key Differences between Location Services Using Cisco 2710 and Context-Aware Mobility Solution
Overview: Context-Aware Location Services for Tag and Client Tracking in Indoor Environments
Deployment and Design Requirements
Designing the Wireless LAN for Location
Deployment Considerations
      General Guidelines – RSSI
      General Guidelines – TDOA
Calibration
Location Rails and Regions
Considerations for Deploying with Existing Data and Voice Services
Location Optimized Monitor Mode
Deployment Checklist
Frequently Asked Technical Questions
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Related Information

Introduction

This document provides configuration and deployment guidelines, as well as troubleshooting tips and answers to frequently asked technical questions, for those adding the Cisco Mobility Services Engine (MSE) that runs Context Aware Mobility Services to a Cisco Wireless LAN network. The purpose of this document is this:

• Explain the various elements and framework for the Cisco Mobility Solution

• Provide general deployment guidelines to deploy Cisco Mobility Solution

This document does not provide configuration details for the MSE and associated components. This information is provided in other documents and references are provided. Refer to the Related Information section for a list of documents about the configuration and design of Context Aware Mobility Services.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Background Information

The Cisco MSE provides the ability to track the physical location of wireless devices with wireless LAN controllers (WLCs) and Cisco Aironet Lightweight Access Points (LAPs). This solution allows you to track any Wi-Fi device, which includes Wi-Fi clients, Wi-Fi active RFID tags, and rogue access points (APs). It was designed with these requirements in mind:

• Manageability—Cisco Wireless Control System (WCS) is used to administer and monitor the MSE. Moreover, the MSE integrates directly into the wireless LAN architecture, which provides one unified network to manage instead of multiple disparate wireless networks.

• Scalability—The Cisco MSE series can simultaneously track up to 18,000 network elements. The WCS can manage multiple Mobility Services Engines for greater scalability. The controller, WCS, and MSE are implemented through separate devices to deliver greater scalability and performance.

• Security—The MSE, WCS, and wireless LAN controller provide robust secure interfaces and secure protocols to access data. The MSE records historical location information that can be used for audit trails and regulatory compliance.

• Open and standards based—The MSE has a SOAP/XML API that can be accessed by external systems and applications that can leverage location information from the MSE.

• Easy deployment of business applications—The MSE can be integrated with new business applications such as asset tracking, inventory management, location-based security, or automated workflow management.

There are two technologies that are used to track Wi-Fi devices with the Cisco Mobility Solution:

• Received Signal Strength Indication (RSSI)

• Time Difference of Arrival (TDOA)

For more information on these technologies, refer to the Wi-Fi Location-Based Services 4.1 Design Guide.

Received Signal Strength Indication

RSSI is the measured power of a received radio signal. The packets transmitted by any wireless device are received at multiple APs. The APs forward these packets to the WLC along with the correspondent RSSI information measured at the AP. The WLC aggregates this information on a per device basis from different APs. This data is forwarded to the MSE through the Network Mobility Services Protocol (NMSP), a protocol defined and developed by Cisco. The Context Aware Location Engines that reside on MSE use the RSSI data to determine the location of a device.

RSSI is usually preferred for indoor environments or cluttered environment, which can result into reflection of the signals. Unlike TDOA, RSSI does not require time synchronization between APs. When you calculate location with RSSI, the AP coverage at different points on the floor is considered. With this information and the measured RSSI values from different APs, the probability of a device being at different points on the floor is calculated. The location, based on this probability, is returned as the estimated location.

Time Difference of Arrival

When you track tags in outdoor and outdoor-like environments, the TDOA mechanism is used. With TDOA, the location of a WLAN device is determined based on the difference in time of arrival (TOA) of the signal that it transmits as seen by different Wi-Fi TDOA receivers. The TOAs are collected and reported to the Context Aware Engine for Tags, which computes the time-differences-of-arrival between multiple pairs of TDOA receivers. The time required for a given message to be received by different TDOA receivers is proportional to the length of the transmission path between the mobile that transmits the device and each TDOA receiver. Consequently, this mechanism of calculation device location requires time synchronization between the TDOA receivers.

In order to compute a position, this method requires a set of at least three TDOA receivers. The distance between TDOA receivers is relatively larger than the distance between APs that are required for indoor RSSI positioning. As with RSSI positioning, this method relies on unidirectional communication (beaconing tag, no association required).

Refer to the AeroScout TDOA Deployment Guide for more information.

System Architecture

The MSE integrates with the Cisco centralized wireless LAN architecture. This device sits outside of the data path of the wireless LAN and works with both the WCS and controllers to track device locations (see Figure 1).

APs can detect devices both on the channels where they service clients and on all other channels by periodically scanning, while still providing uninterrupted data access to their wireless clients. The gathered raw location data is then forwarded from each AP upstream to its controller. Communication between the MSE and WLC is carried out through the NMSP.

The Cisco WCS is used to manage and configure the MSE and is also the visual front-end of the MSE to display Wi-Fi devices that are tracked. All device details and specific historical location information can be accessed with the MSE northbound API. The WCS uses this interface to visualize the information.

The Cisco Mobility Solution consists of two location engines:

• Context Aware Engine for Clients (Cisco engine)

• Context Aware Engine for Tags (partner engine)

The Context Aware Engine for Clients is an RSSI-based solution to track Wi-Fi client devices in indoor, low-ceiling environments. This engine ships by default on all Cisco MSE servers. In addition to the Cisco MSE, you need to purchase two additional components for client tracking:

• Client tracking license with appropriate client count

• Cisco WCS with location

The Context Aware Engine for Tags uses both an RSSI and TDOA-based engine and is intended to be used when it tracks Wi-Fi devices in indoor, low-ceiling (RSSI), indoor high-ceiling (TDOA), and outdoor (TDOA) environments. This engine must be purchased separately and installed/enabled separately. You need to purchase these additional components for client tracking:

• Tag tracking license with appropriate client count

• Cisco WCS with location

For more information on client and tag licensing, refer to the Cisco 3300 Series Mobility Services Engine Data Sheet.

Hardware Requirements

Because the MSE is part of the Lightweight Access Point Protocols (LWAPP) architecture, this document assumes the user already has an LWAPP- based wireless network in place. Both an explanation of the various LWAPP components that you can use to track location, as well as a hardware compatibility matrix are provided to ensure that all required LWAPP-compatible infrastructure is in place to support location tracking.

Key Differences between Location Services Using Cisco 2710 and Context-Aware Mobility Solution

Cisco provides location-based services with the Cisco 2710-based solution. Table 4 provides a comparison between the two solutions and shows the advantages of the MSE solution.

The MSE provides the ability to track up to 18,000 devices (tags, clients, and rogue clients/APs). This floor map illustrates the scale and variety of classes of devices that can be tracked by the MSE. The WCS provides the capability to define search parameters to display only in a subset of devices. For example, a biomedical user wants to see only infusion pumps and EKG machines named with friendly identifiers rather than rogue devices or devices with cryptic MAC or IP addresses.

Client:

Tag:

Rogue AP (red=malicious, green=friendly, grey=unclassified)

Overview: Context-Aware Location Services for Tag and Client Tracking in Indoor Environments

When the Cisco centralized wireless LAN architecture and Context-Aware Location Services are used, administrators can determine the location of any 802.11-based device as well as the specific type of each device. Clients, rogue APs, rogue clients, and active tags can all be identified and located by the system.

Clients are all devices associated with controller-based LAPs on a wireless network.

A rogue AP is defined as any access point that is determined not to be part of the wireless LAN that detected it. This consists of all non-system APs within network reachability of LAPs, which includes those on the wired network or those on another wired network (such as the AP of a neighbor). Because all LAPs use a hash as part of the beacon frame with a special key, even spoofed infrastructure access points are identified as rogue APs rather than mistaken to be legitimate access points flagged in the WCS as spoof access points.

Rogue clients are all client devices that are associated to rogue APs. Active tags are Cisco CCX 802.11-based RFID tags within range of infrastructure APs.

Deployment and Design Requirements

Consider the type of devices involved and how many devices are tracked. Tracking of any of the four device types can be configured. Determine the total number of devices and plan to deploy one MSE for every 18,000 simultaneously tracked devices.

Dependent upon network requirements, the placement of the MSE in relation to the WCS can be adjusted to fit specific site needs. Where a single WCS is used for wireless LAN management, one or more MSE servers can be used to track 18,000 or more devices. When multiple WCS servers are used to manage separate wireless LANs, a single MSE can be used by all WCS servers to track each device if the aggregate number of tracked device does not exceed 18,000 elements.

Designing the Wireless LAN for Location

The Cisco Aironet 1100 and 1200 Series APs are supported by the WLCs (2106 and 4400 Series controllers, as well as the Cisco Catalyst 6500 Series Wireless Services Module (WiSM)), which forward device information to the MSE. Proper antenna configuration on these APs is important for location accuracy. Cisco Aironet 1000 Series APs for Context-Aware software are supported only with version 4.2.xxx (xxx >112)

Note: The Cisco Aironet 1000 Series APs are an End-of-Life and End of Sale product. The Cisco Aironet 1000 Series APs for Cisco Context-Aware Solution are supported only with version 4.2.xxx (xxx >112). Only the Cisco Context-Aware Solution on the Cisco 3300 Series Mobility Services Engine is supported. No other services on the Cisco 3300 Series Mobility Services Engine are and will be supported. The 5.x.xxx versions and future versions of software will not support the Cisco Aironet 1000 Series APs. Customers are encouraged to migrate to the Cisco Aironet 1300, 1240, or 1250 Series APs to utilize the benefits of the latest features introduced. Contact Cisco for more information about the replacement products.

Deployment Considerations

General Guidelines – RSSI

In order to determine the optimum location of all devices in the wireless LAN coverage areas, you need to consider the access point density and location.

Ensure that no fewer than three APs provide coverage to every area where device location is required. Optimal accuracy requires four or more APs. APs must surround the location of Wi-Fi device that is tracked. One AP must be placed every 50-70 linear feet (~17-20 meters). This translates into one AP every 2500 to 5000 square feet (~230-450 square meters). AP antennas must be placed at a minimum height of 10 feet and a maximum height of 20 feet.

Follow these guidelines to increase the likelihood that APs will detect tracked devices.

Rarely do two physical environments have the same RF characteristics. Users might need to adjust those parameters to their specific environment and requirements.

These basic rules contribute to location accuracy:

1. Place APs along the periphery of coverage areas to help locate devices close to the exterior of rooms and buildings (see Figure 3). APs placed in the center of these coverage areas provide good data on devices that otherwise appear equidistant from all other APs.

   Figure 3: Access Points Clustered Together Can Result in Poor Location Results

   

   AP:

   Wi-Fi device:

2. Increase overall access point density and move APs towards the perimeter of the coverage area to improve location accuracy (see Figure 4).

   Figure 4: Improved Location Accuracy because of Increased Density

   

3. In long and narrow coverage areas, do not place APs in a straight line (see Figure 5). Preferred deployment is to stagger APs so that each AP is more likely to provide a more unique snapshot of device location.

   Though the deployment in Figure 5 can provide enough access point density for high bandwidth applications, location suffers because the view of a single device for each AP is not varied enough. Thus, location is difficult to determine.

   Figure 5: Avoid Deployment of APs in Straight Line

   

4. Move the APs to the perimeter of the coverage area and stagger them. Each has a higher likelihood to offer a distinctly different view of the device, which results in higher location fidelity (see Figure 6).

   Figure 6: Improved Location Accuracy by Staggering Around Perimeter

   

5. A number of design factors must be accounted for when you design a wireless LAN for Context Aware Mobility Solution, as well as plan for voice. Most current wireless handsets support only 802.11b, which only offers three non-overlapping channels. As a result, wireless LANs designed for telephony tend to be less dense than those planned to carry data. Also, when traffic is queued in the Platinum QoS bucket (typically reserved for voice and other latency sensitive traffic), LAPs postpone their scanning functions that allow them to peak at other channels and collect, among other things, device location information. As such, the user has the option to supplement the wireless LAN deployment with APs set to monitor-only mode. APs that only monitor do not provide service to clients and do not create any interference. They simply scan the airwaves for device information (see Figure 7).

   Figure 7: Less Dense Wireless LAN Installations

   

   Less dense wireless LAN installations, such as those of voice networks, find their location fidelity greatly increased by the addition and proper placement of Location Optimized Monitor Mode APs.

6. Perform a coverage verification with a wireless laptop, handheld, and possibly a phone to ensure that no fewer than three APs are detected by the device. In order to verify client and asset tag location, ensure that WCS reports client devices and tags within the specified accuracy range (10m, 90%).

General Guidelines – TDOA

With TDOA-based deployment, a minimum of three receivers is required, but four receivers yield better accuracy results. These are the general rules for TDOA receiver density:

• Outdoors—average density must be one TDOA receiver for every 20,000-50,000 square feet.

• Large indoor areas—average density must be one TDOA receiver every 5000–14,000 square feet.

In certain scenarios, large areas might need to be divided into subareas. For example, in the case where a large warehouse is sectioned off by a wall, this might need to be designed as two subareas. Best results are when line of sight is maintained between synchronization source and the TDOA receivers. Best accuracy results are obtained when line of sight is maintained between the synchronization source and the TDOA receivers.

Additional guidelines for Wi-Fi TDOA receiver placement:

• TDOA receivers must be placed along the outside perimeter and evenly spaced.

• Additional TDOA receivers might be needed within the boundary of the perimeter receivers, which depends on the size of the area.

• TDOA receivers must be evenly spaced, which forms an equilateral triangle (when three TDOA receivers are used), or squares (four or more TDOA receivers).

In reference to Wi-Fi TDOA receiver antennas, use diversity antennas to address multipath issues. Wi-Fi TDOA receivers placed along the perimeter of the covered area must include directional antennas in order to concentrate the reception in the covered area only. In the corner of a perimeter, use a 90-degree directional antenna and along the perimeter, use a 180-degree directional antenna. Omni-directional antennas must be used with TDOA receivers located within the perimeter. Receiver antennas must point both to the synchronization source (most preferably line of sight) and to the area in question.

Antennas must be placed in areas where they are not obstructed by obstacles such as concrete walls, large metallic objects, or densely covered tree areas. They must be installed with a good line of sight (as much as possible) to the covered area. The preferred mounted height is 10–16 feet above the tracked asset surface. When this is not possible due to the environment, then the coverage pattern (for example, elevation pattern - typical antennas have an elevation of approximately 35 degrees) must be adjusted accordingly. Along the perimeter, antennas at high placements must be tilted towards the coverage area (up to 30 degrees down to compensate for the elevation).

For more information, refer to the AeroScout TDOA Deployment Guide .

Calibration

Location accuracy is dependent on two factors:

• AP placement and number of APs

• Correct RF signal characteristics of AP for given environment – Accurate AP heat maps

Each environment is unique, and the signal characteristics of an AP in a given environment vary widely. The WCS provides a mechanism for a user to calibrate signal characteristics for their environment. The first step to optimize accuracy is to ensure that the AP deployment is in accordance with the location deployment guidelines summarized in the previous section. If you attempt to improve location accuracy through calibration with inadequate AP coverage, the placement potentially cannot provide adequate results.

Three default calibration models are provided with the WCS:

• cubes and walled offices

• drywall office only

• outdoor open space

Each model is based on the most common environments in a typical customer environment.

If the provided RF models do not sufficiently characterize the floor layout, calibration models can be created with the WCS and applied to the floor to better represent the attenuation characteristics of a given environment. In environments where many floors share common attenuation characteristics, one calibration model can be created and then applied to all similar floors.

Use a laptop or other wireless device (must be CCXv2 client) to perform the calibration process. Two calibration modes are supported:

• Linear calibration—data collected between 2 different points (straight line)

• Point calibration—client at fixed location

Use both mechanisms, linear calibration for large open areas and hallways and point calibration for cubes and office locations within the calibration process.

For further details on how to create and apply calibration models, refer to the Cisco Location Appliance Configuration Guide, Release 4.0.

Location Rails and Regions

Even when the correct steps are taken to ensure proper AP placement, there are cases when devices that are tracked show up in areas at the floor or building level where these devices are known to not exist. The Rails and Regions feature provides a mechanism for a network administrator to define inclusion and exclusion areas for location services. This feature allows for specific regions on a map to be defined as within or outside the scope of a valid location area.

Three types of regions can be specified:

• Location inclusion region—Tracked device cannot be outside of this polygon (Examples: Outside of building outer walls).

• Location exclusion region—Tracked device cannot be inside of this polygon (Examples: Open Atrium).

• Rails—Tracked device must be within defined area with narrow band. Typically used within exclusion region (for example: Conveyor belt).

After Rails and Region areas have been defined in the WCS, the floor update needs to be pushed from the WCS to the MSE through the synchronization process.

Note that Location Rails and Regions only works with Context Aware Engine for Clients.

Considerations for Deploying with Existing Data and Voice Services

In customer environments where current wireless networks are in place, the overlaying Context Aware Mobility Solution requires a re-evaluation of the overall deployment for accuracy and potential coverage holes. These are general guidelines that must be used:

• Maximum effective AP: spacing in most sites is 40-70 feet

• Minimum of three APs within the transmission range of every client (recommend four APs for redundancy)

• Place perimeter APs first. APs must surround the desired areas of location coverage.

• Next, place interior APs to minimize coverage gaps.

• In quadrilateral area, a minimum of four APs must be installed at the four corners of the area.

• Factors that affect accuracy: AP placement, wall materials, large moving objects, RF interference.

• You might need to floor space into sub-areas and design sub-areas independently to account for large barriers that obstructs RF signals.

• APs can preferably be positioned along and within the perimeter of an enclosed area.

• APs must be distributed evenly. For example, APs must be relatively equal distance from each other.

• Physical placement of APs must be non-colinear, even when placed at equal distances from each other.

• Use Location Readiness Tool in the WCS to gauge effectiveness of overall floor coverage.

• Geometric shapes formed by the distribution of APs affects accuracy:

  • Equilateral triangle placement yields better accuracy than APs that form an obtuse triangle.

  • Square deployment placement yields better results than APs that form rectangles.

Location Optimized Monitor Mode

Starting with software version 5.0, Cisco Aironet 1100 and 1200 APs can operate as Location Optimized Monitor Mode (LOMM) APs. This feature can be used for these reasons:

• Location and voice co-existence: With monitor mode AP in a mixed deployment, there is no negative impact on voice because location needs increased the AP density.

• Low touch, does not impact current infrastructure.

LOMM for location can be used when you track clients or tags.

LOMM APs are good to improve coverage when you track locations, regardless of where Wi-Fi coverage gaps exist, either in the perimeter or within the convex hull. LOMM APs do not interfere with local mode AP operation. In order to optimize the monitoring and location calculation of tags, LOMM can be enabled on up to four channels within the 2.4GHz band (802.11b/g radio) of an AP. This allows you to focus channel scans only on those channels on which tags are usually programmed to operate (such as channels 1, 6, and 11).

Deployment Checklist

• Verify that Wi-Fi coverage utilizes the site survey tool, as well as the WCS (Location Readiness tool).

• Verify that AP density guidelines are met. Ensure proper AP perimeter coverage.

• Verify AP placement to eliminate coverage holes. Utilize Location Optimized Monitor Mode APs to fill in coverage holes.

• Use the calibration tool in the WCS to calibrate signal characteristics for the specific environment.

• Use Location Rails and Regions (for client tracking) to include or exclude specific areas on the floor map where Wi-Fi clients can and cannot appear.

Use this checklist as a guideline when you consider the deployment of Context-Aware Services on your network architecture:

AP/Controller Software Compatibility for MSE Software 5.1.xxx

WCS Software Compatibility for MSE Software 5.1.xxx

5.1.xxx or later

What does the customer want to track (Circle One): Tags, Clients, or both

What are the accuracy requirements for this deployment?

The deployment of the Context-Aware Services is not complete unless all questions listed here are answered as Yes:

• Has an RF site survey been conducted?

• Do APs surround the desired coverage area?

• Has the density requirements (of APs) for every 50-70 feet been met?

• Has the environment been calibrated for Context-Aware Mobility Services?

• Has the WCS built-in Location Readiness tool verified the absence of coverage holes?

• Do the APs and wireless controller hardware and software versions conform to the requirements of the Context-Aware Software requirements?

• Is the number of tracked devices less than or equal to the maximum license purchased?

• Have the QoS settings of the controller been set for Context-Aware services?

• Have the accuracy requirements of the deployment been met with the Location Accuracy Tool in the WCS?

Frequently Asked Technical Questions

Q. What is RF fingerprinting? Is it the same as RF triangulation?

A. RF fingerprinting is a method of location determination with two focuses: to understand how radio waves interface in a specific environment of the wireless LAN, and to apply these attenuation characteristics to device signal information, so a location can be determined. Triangulation does not take environmental variables into account, and instead relies only on signal strength readings to approximate device location. RF fingerprinting takes specific building characteristics into account because they can affect the propagation of RF signals and the accuracy of location determination.

Q. What kind of location fidelity can I expect?

A. Location is statistical in nature. Cisco cites location accuracy specifications to within ten meters 90% of the time and five meters 50% of the time.

Q. Is the information real time?

A. The response time of location information, as well as associated client information, is primarily a function of system processing. Response times can typically range from a few seconds to a few minutes.

Q. How scalable is the MSE?

A. The Cisco MSE 3350 can track up to 18,000 devices. For support of more devices, additional MSEs can be added to the same system. The upper limit for simultaneous devices is based on the processing capacity of the MSE.

Q. How long can I store location history?

A. The amount of location history that the MSE can store and replay is configurable. The default value is 30 days.

Q. How does location traffic impact my network?

A. The amount of location traffic is dependent on the number of controllers, APs, and ultimately the number of devices that are tracked by a given network infrastructure. As the network grows, more traffic is forwarded from the APs to wireless controllers, which, in turn, are forwarded to the MSE. The amount of traffic for an individual measurement is very small, but the number of measurements is dependent upon the number of devices and how often measurements are taken.

Q. How is the MSE managed?

A. In the case of client tracking with the Context Aware Engine for Clients, all configuration and management of the MSE is performed through the WCS, beyond the initial CLI command-driven setup. When the Context Aware Engine for Tags is used (tracking tags in indoor and outdoor/outdoor-like environments), both Cisco (WCS) and AeroScout (System Manager) network management solutions are required.

Q. What is required of my wireless LAN architecture to support the MSE?

A. The MSE only works with Cisco Centralized Wireless LAN architecture, such as an LWAPP-enabled infrastructure. Proper AP placement is imperative to location. APs must be placed close to the perimeter of coverage areas and internally as described in this document. See the section entitled Considerations for Deploying with Existing Data and Voice Services. WCS with a Context Aware Engine license is required.

Q. What is the difference between the location provided in the WCS versus the MSE?

A. The WCS base indicates which AP can detect a given device, as well as the signal strength at which that device is detected. WCS with Location uses advanced RF fingerprinting and can pinpoint the location of a single device in on-demand fashion. The MSE uses the same location method as the WCS with location, but it can track up to 18,000 devices simultaneously when it uses the Cisco MSE 3350. This allows third-party applications to leverage device information history for applications such as asset tracking.

Q. Do I need client software to locate clients?

A. Client software is not needed. Because location is directly integrated into the wireless LAN infrastructure, APs listen to Wi-Fi devices as they normally do for data, voice, and other applications. CCX Clients are tracked better than non-CCX clients. Consequently, Cisco recommends that you purchase clients that are CCX compatible (v4 or v5).

Q. How long can Wi-Fi tags be operational before the battery needs to be replaced?

A. Tag battery life is a function of specific device battery longevity, as well as how often they beacon or blink. The tags can last anywhere from 100 days to a year or even longer. Some manufacturers advertise that they can last 3-5 years, but it is dependent on the beacon rate.

Q. What is the cost of Wi-Fi tags?

A. Contact a tag manufacturer. Cisco does not manufacture or resell tags. Also, tag prices are variable and depend on volume. These tags are higher priced than passive RFID tags because they provide more continuous location visibility and reusable battery-powered tags. They actively send signals, that typically provide greater ranges (several hundred feet), and come in a variety of form factors with multiple mounting options. The use of active RFID is generally associated with more continuous tracking of more mobile high value assets or high liability assets relative to items that are generally tracked by passive RFID.

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Related Information

• Cisco 3350 Mobility Services Getting Started Guide
• Cisco 3300 Series Mobility Services Engine Configuration Guide, Release 5.1
• Cisco Wireless LAN Controller Configuration Guide
• AeroScout Support
• Indoor Deployment Guide for Wi-Fi Access Points
• AeroScout Exciter Deployment Guidelines
• AeroScout Engine for Cisco Mobility Services Engine
• TDOA Deployment Guide
• Technical Support & Documentation - Cisco Systems