448 CHAPTER 16: MONITORING THE NETWORK
If the SNR, Associated Clients, or Receiver Threshold column is red, this indicates that the threshold configured for this parameter has been exceeded. (See “Changing Monitoring Settings” on page 500.)When looking at graphed data, you can see the data in absolute or delta values. Delta (rate of change) values are calculated with the following equation: value at end of polling interval - value at beginning of polling interval
time difference (in seconds)
Table57 RF Trends Columns
Column Description
Radio MAP name and radio number.
SNR Signal-to-noise ratio of the last data packet received by the
radio.
Throughput Rate at which data is transmitted by the radio, in bits per
second.
Authorized Clients Number of authorized clients associated with the radio.
Client Failures Combined number of the following types of errors:
802.1X failures
association failures
authentication failures
authorization failures
802.11 Packet Errors Number of frames received by the MAP radio that had
physical layer errors on the active channel. These errors
can indicate interference from a non-802.11 device.
Non-802.11 PHY Errors Number of times the radio detected energy on the active
channel that either was not recognizable as an 802.11
frame, or was above the power level of background noise.
Re-transmits Number of retransmitted packets sent from the client to
the radio on the active channel. Retransmissions can
indicate that the client is not receiving ACKs from the MAP
radio.
Receiver Threshold Radio’s hearing sensitivity, in decibels (dB).
Noise Floor (dBm) Received signal strength at which the MAP can no longer
distinguish 802.11 packets from ambient RF noise. A value
around -90 or higher is good for an 802.11b/g radio. A
value around -80 or higher is good for an 802.11a radio.
Values near 0 can indicate RF interference.