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command line values Airtime documentation?

  • 1.  command line values Airtime documentation?

    Posted 12-20-2018 07:53

    Anyone know where to find documentation on the commandline output? show int wifiX

    I was looking at two 2.4 radio's, and noticed a big differnce in airtime values the first one has 3 user connections, the second 10 connections. Also why one says "fair" & the other one says "High collision"?

     

     

    Rx airtime=8.30 s vs Rx airtime=3318.96 s

     

    Summary state=Fair;

    Rx airtime=8.30 s; Tx airtime=306.82 s; CRC error airtime=5.08 s;

    Rx airtime percent=2.64%; Tx airtime percent=75.35%; CRC error airtime percent=0.08%;

    Tx utilization=51%; Rx utilization=10%; Interference utilization=9%; Total utilization=70%;

     

     

    Summary state=High collision;

    Rx airtime=3318.96 s; Tx airtime=20628.65 s; CRC error airtime=2131.13 s;

    Rx airtime percent=0.25%; Tx airtime percent=1.30%; CRC error airtime percent=0.00%;

    Tx utilization=2%; Rx utilization=8%; Interference utilization=4%; Total utilization=14%;

     



  • 2.  RE: command line values Airtime documentation?

    This message was posted by a user wishing to remain anonymous
    Posted 12-20-2018 13:55

    You really have a two part question. I'll answer part 2 first, about the values of "Fair" and "High Collisions". This was taken from an Aerohive support document (of which I can't seem to find at the moment).

     

    // Show int wifi0/1 and the meaning behind if the Summary State

     

    WiFi Status Summary

     

    (This option is unavailable on Aerohive switches and VPN gateways.) HiveManager can generate a report that summarizes the status of the wireless interfaces for a selected device or devices. You can use this report to identify and correct issues such as overcrowded channels, high collision rates, and SNR (signal to noise ratio) problems.

     

    To generate a WiFi Status Summary, from either the monitor or config view, first select the check box next to a device or devices for which you want a summary, then click Utilities > Status > WiFi Status Summary. For the selected device or devices, you will see information about the WiFi interfaces specifically, and about the device (referred to as station in the summary) in general.

     

    There are five possible states for the WiFI interfaces:

     

    Good: The CRC and Tx error rates are less than 5%, and channel utilization is less than 50%.

     

    Fair: The CRC and Tx error rates are less than 10%, and channel utilization is less than 65%.

     

    Channel RF Overcrowded: The channel utilization rate is 65% or greater.

     

    High Collision: The CRC error rate is 10% or greater.

     

    High Tx Error: The transmit error ration is more than 10%, which can occur when the RF environment is overcrowded and the collision rate is high.

     

    • In some cases, the interface will meet the requirements for both Channel RF Overcrowded and High Collision. In these cases, both states are listed in the report.

    There are four states for the station. The station must meet all required conditions to be identified as being in one of these four states:

     

    Good: SNR must be greater than 20 dB. The Tx retry ratio is less than 5%.

     

    Fair: SNR is less than 20 dB, but greater than 15 dB. The Tx retry ratio is less than 10%.

     

    Poor: The SNR is less than 15 dB.

     

    High Retries: The Tx ratio is greater than 10%

     

     

    Your first inquiry about air time utilization is a bit more complex. Air time utilization comes from all sources/stations that the AP can decode on the channel(s) it is using (2.4 GHz and 5 GHz respectively). Since the 2.4 GHz is traditionally more congested (fewer channels to take advantage or, most all devices support 2.4 GHz - some exclusively) there is simply more chatter on that frequency. We can see from your output that the airtime utilization looks to be sourcing from the AP though (Tx utilization is the % amount of airtime the AP is transmitting).

     

    A few more commands that might shed more light onto things.

     

    Show station - this will tell us which frequency/SSIDs your stations are connected to on this AP. I suspect more or more heavy users on 2.4 GHz.

     

    Show acsp neighbor - this will show us what other RF this AP hears. On its respective channels as well as possibly on other channels depending on how your radio profiles are configured for it to do off channel scanning. If we hear a lot of "RF" from other hardware on the same channel, this could also be the source of a good bit of the utilisation.

     

     



  • 3.  RE: command line values Airtime documentation?

    Posted 12-20-2018 15:45

    Thank allot, that was the info I was looking for!

     

    I still don't see where the "Tx airtime = s" fits in or what it indicates. The value doesn't really move with the "Tx airtime percent" high or low value.

     

    Tx airtime percent=75.35% => i'm downloading allot of data on 2.4 => Tx airtime=306.82 s

    Tx airtime percent=1.30%; => some idle phones on 2.4 => Tx airtime=20628.65 s