Cisco 1552 Series, Руководство по установке

Страница: 54 / 139

2-40
Cisco Aironet 1552 Series for Hazardous Locations Installation Guide
Chapter 2 Before You Begin
Installation Guidelines
•
The access points can be installed at any height, but best throughput is achieved when all the access
points are mounted at the same height. Cisco recommends installing the access points no higher than
40 feet to allow support for wireless clients on the ground.
Note
To calculate path loss and to determine how far apart to install access points, consult an RF planning
expert.
Site Surveys
Every network application is a unique installation. Before installing multiple access points, you should
perform a site survey to determine the optimum use of networking components and to maximize range,
coverage, and network performance.
Consider the following operating and environmental conditions when performing a site survey:
• Data rates—Sensitivity and range are inversely proportional to data bit rates. The maximum radio
range is achieved at the lowest workable data rate. A decrease in receiver sensitivity occurs as the
radio data increases.
•
Antenna type and placement—Proper antenna configuration is a critical factor in maximizing radio
range. As a general rule, range increases in proportion to antenna height. However, do not place the
antenna higher than necessary, because the extra height also increases potential interference from
other unlicensed radio systems and decreases the wireless coverage from the ground.
•
Physical environment—Clear or open areas provide better radio range than closed or filled areas.
•
Obstructions—Physical obstructions such as buildings, trees, or hills can hinder performance of
wireless devices. Avoid locating the devices in a location where there is an obstruction between the
sending and receiving antennas.
• Applications and type of devices to be used on the WLAN.
Before Beginning the Installation
Before you begin the installation process:
•
Ensure that a site survey has been performed.
•
Ensure that your network infrastructure devices are operational and properly configured.
• Ensure that your controllers are connected to switch trunk ports.
•
Ensure that your switch is configured with untagged access ports for connecting your access points.
• Ensure that a DHCP server with Option 43 configured is reachable by your access points, or
manually configure the controller information in the access point (for additional information, refer
to the
Appendix F, “Configuring DHCP Option 43” ).
•
Become familiar with the access point installation components (see the “Becoming Familiar with
Access Point Installation Components” section on page 2-41 ).