RSSI values are negative because that's the nature of the dBm scale. The unit "dBm" means Decibels (dB) relative to a standard of 1 milliwatt (m).
A decibel scale is logarithmic. Your reference unit is always 0 dB. 10 times the reference unit is 10 dB. 100 times the reference unit is 20 dB. 1000 times the reference unit is 30 dB, and so forth.
As signal goes down, your dB values become negative: 1/10th of the reference unit is -10 dB, 1/100th of the reference unit is -20 dB, 1/1000th of the reference unit is -30 dB.
So when we're dealing with RSSI, as you get farther and farther away, your numbers become more and more negative. The FCC limits broadcast power to 100 mW... that's 20 dBm. But a single receiver will never absorb more than a tiny fraction of that energy, and that amount decreases as you get further and further from the transmitter.
In the real world, your wireless device will almost never absorb more than about a thousandth of a milliwatt even when you're right on top of the AP... that's -30 dBm. As you get farther away, signal strength drops off and the dBm values become even more negative. Remember that each -10 dBm means that the wattage of the signal has been divided by 10. So, where -30 dBm means 0.001 mW, -40 dBm means 0.0001 mW, -50 dBm means 0.00001 mW, and so forth.
it depends on what your looking for, RSSI is a measure of the received power as seen by the radio, which means that includes the gain of the antenna and such.
there is no standard correlation between RSSI and Signal Strength Percentages and you can't directly compare a transmit power of 20dbm to a -65dbm signal strength except that if you follow the standard logarithmic equation you can figure it out.
100mw = 20dbm
so to get to -64dbm is approximately 0.00000037 mw
Transferring Crash file from standby:
Login to the Active WLC in HA.
(Cisco Controller) >transfer upload datatype crash
(Cisco Controller) >transfer upload filename <Desired filename>
(Cisco Controller) >transfer up...
This is the start of a display filter cross reference between Wireshark and OmniPeek.
The 1st installment is a table of advanced filters. More filters will be added as time allows.
It is a living doc, so check back for changes every so often
Please feel ...
I have created a Powershell script to automatically add a Wireless Guest User on Cisco WLCs. (tested on 2500 Series)
The script should be completely self explanatory.
Powershell SNMP Module (Install-Module -Name SNMP)
SNMP Write Access to...