Installation guide

81
Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
Deployment Best Practices
• Minimize the amount of exposure to those “flattened” areas of the signal strength versus distance
curve where there is little change in signal strength as distance increases
Therefore, in general, Cisco recommends the following:
• Antenna installation be performed at heights of 10 feet or less for optimum location fidelity.
Antenna heights in this range have been found to be most conducive to good location fidelity.
• Antenna installations above 20 feet be avoided.
Traffic Considerations
As shown in Figure 8, the Cisco Location Appliance and the Cisco WCS are members of the Cisco
Unified Wireless Network, with each deployed as a separate hardware component for optimum
scalability and maximum flexibility. This section discusses the traffic considerations to keep in mind
when deciding where to place each of these components in a network design.
In most cases, when all components are deployed via a well-designed 10/100/1000 infrastructure (a large
healthcare campus facility, for example), wired LAN bandwidth is normally sufficient for proper
operation of the LBS solution. It is definitely good practice, however, to reduce the demands on
controller CPU by avoiding excessive and unproductive polling of controllers for as described in Traffic
Between the Location Appliance and WLAN Controllers, page 81.
In deployments supporting a large number of geographically distributed locations across a WAN, further
consideration regarding data traffic load may be required. This depends on the polling categories and
intervals selected along with the overall usage and capacity of any WAN links involved. Every effort
should be made to assure sufficient WAN bandwidth is available to accommodate added SNMP traffic
from routine location server polling of controllers, as discussed in Traffic Between the Location
Appliance and WLAN Controllers, page 81. In addition, location appliance and WCS placement should
be chosen to ensure that the traffic considerations discussed in Traffic Between the Location Appliance
and WCS, page 84 are properly accommodated. This is typically achieved using LAN or high-speed
WAN technology with sufficient available bandwidth.
Traffic Between the Location Appliance and WLAN Controllers
When first installed, all polling between the location appliance and the WLAN controller is disabled by
default (shown in Figure 54); that is, the location appliance does not poll the controllers for information
regarding clients, rogues, active RFID tags, or statistics. Consequently, WCS does not display this
information in floor maps until polling is enabled and data is collected from the controllers. Polling must
be enabled via the checkboxes on Locate > Location Servers > Administration > Polling Parameters, as
shown in Figure 54.