Cisco UNIFIED 9971, Руководство по развертыванию

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Cisco Unified IP Phone 9971 Wireless LAN Deployment Guide
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Cisco Unified IP Phone 9971 Overview
The Cisco Unified IP Phone 9971 is the platform that provides communication within enterprises. The levels of voice quality
performance that have come to be expected from Cisco products are maintained in the Cisco Unified IP Phone 9971 with the
inclusion of Cisco Compatible eXtensions (CCX).
Cisco's implementation of 802.11, employing CCX, permits time sensitive applications such as voice to operate efficiently
across campus wide wireless LAN (WLAN) deployments. These extensions provide fast roaming capabilities and an almost
seamless flow of voice traffic, whilst maintaining security as the end user roams between access points.
It should be understood that WLAN uses unlicensed spectrum, and as a result it may experience interference from other devices
using the unlicensed spectrum. The proliferation of devices in the 2.4 GHz spectrum, such as Bluetooth headsets, Microwave
ovens, cordless consumer phones, means that the 2.4 GHz spectrum may contain more congestion than other spectrums. The 5
GHz spectrum has far fewer devices operating in this spectrum and is the preferred spectrum to operate the Cisco Unified IP
Phone 9971 in order to take advantage of the 802.11a data rates available. Despite the optimizations that Cisco have
implemented in the Cisco Unified IP Phone 9971, the use of unlicensed spectrum means that uninterrupted communication can
not be guaranteed, and there may be the possibility of voice or video gaps of up to several seconds during multimedia
conversations. Adherence to the deployment guidelines will reduce the likelihood of these voice and video gaps being present,
but there is always this possibility. Through the use of unlicensed spectrum, and the inability to guarantee the delivery of
messages to a WLAN device, the Cisco Unified IP Phone 9971 is not intended as a medical device and should not be used to
make clinical decisions.
Requirements
The Cisco Unified IP Phone 9971 is an IEEE 802.11a/b/g device that provides voice and video communications.
The wireless LAN must be validated to ensure it meets the requirements to deploy the Cisco Unified IP Phone 9971.
Site Survey
Before deploying the Cisco Unified IP Phone 9971 into a production environment, a site survey must be completed by a Cisco
certified partner with the advanced wireless LAN specialization. During the site survey the RF spectrum can be analyzed to
determine which channels are usable in the desired band (2.4 GHz or 5 GHz). Typically there is less interference in the 5 GHz
band as well as more non-overlapping channels, so 5 GHz is the preferred band for operation and even more highly
recommended when the Cisco Unified IP Phone 9971 is to be used in a mission critical environment. The site survey will
include heatmaps showing the intended coverage plan for the location. The site survey will also determine which access point
platform type, antenna type, access point configuration (channel and transmit power) to use at the location. It is recommended
to select an access point with integrated antennas for non-rugged environments (e.g. office, healthcare, education, hospitality)
and an access point platform requiring external antennas for rugged environments (e.g. manufacturing, warehouse, retail).
See the
Designing the Wireless LAN for Voice section for more information.
Refer to the Steps to Success website for additional information.
http://www.cisco.com/go/stepstosuccess
RF Validation
In order to determine if VoWLAN can be deployed, the environment must be evaluated to ensure the following items meet
Cisco guidelines.
Signal
The cell edge should be designed to -67 dBm where there is a 20-30% overlap of adjacent access points at that signal
level.