Requirements; Site Survey - Cisco 8861 Deployment Manual

Requirements

The Cisco IP Phone 8861 and 8865 are IEEE 802.11a/b/g/n/ac devices that provide voice communications.
The environment must be validated to ensure it meets the requirements to deploy the Cisco IP Phone 8861 and 8865.

Site Survey

Before deploying the Cisco IP Phone 8861 and 8865 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 (5 GHz or 2.4 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 IP Phone 8861 and 8865 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).
The wireless LAN must be validated to ensure it meets the requirements to deploy the Cisco IP Phone 8861 and 8865.
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.
This ensures that the Cisco IP Phone 8861 and 8865 always have adequate signal and can hold a signal long enough in
order to roam seamlessly where signal based triggers are utilized vs. packet loss triggers.
Also need to ensure that the upstream signal from the Cisco IP Phone 8861 and 8865 meets the access point's receiver
sensitivity for the transmitted data rate. Rule of thumb is to ensure that the received signal at the access point is -67
dBm or higher.
It is recommended to design the cell size to ensure that the Cisco IP Phone 8861 and 8865 can hold a signal for at least
5 seconds.
Channel Utilization
Channel Utilization levels should be kept under 40%.
The Cisco IP Phone 8861 and 8865 convert the 0-255 scale value to a percentage, so 105 would equate to around 40%
in the Cisco IP Phone 8861 and 8865.
Noise
Noise levels should not exceed -92 dBm, which allows for a Signal to Noise Ratio (SNR) of 25 dB where a -67 dBm
signal should be maintained.
Also need to ensure that the upstream signal from the Cisco IP Phone 8861 and 8865 meets the access point's signal to
noise ratio for the transmitted data rate.
Packet Loss / Delay
Per voice guidelines, packet loss should not exceed 1% packet loss; otherwise voice quality can be degraded
significantly.
Jitter should be kept at a minimal (< 100 ms).
Retries
802.11 retransmissions should be less than 20%.
Cisco IP Phone 8861 and 8865 Wireless LAN Deployment Guide
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