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Occasional Contributor II

802.11ac snfifer options and cli output

Hello,

 

I need some help sniffiing 802.11ac.

 

1) Is the a cli tip to show the modulation being used by 802.11ac clients (16-QAM, 256, etc? Can I debug this? How can I see this from the cli?

 

2) Any recommendations on a free or paid 802.11ac sniffer?

 

Thank you,

Jay

Guru Elite

Re: 802.11ac snfifer options and cli output

"show ap association client-mac <mac address of client>" will show you the spatial streams, whether sgi is in play and the channel width.  There is not anything that will show you the QAM.

 

Wireshark is a free sniffer.  MAC OSX has a built in wireless sniffer, as well.

 

The controller can do packet captures as well:  http://community.arubanetworks.com/t5/forums/searchpage/tab/message?include_tkbs=true&location=category:Support-Documentation-Downloads&q=packet%20capture


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Occasional Contributor II

Re: 802.11ac snfifer options and cli output

Yes, i would prefer to use wireshark but I beleive it needs the ngpcap and radiotap headers. I do not now how to get the radiotap headers to install on wireshark running on windows?

 

Any instructions/ link?

 

Thank you,

Jay

Re: 802.11ac snfifer options and cli output

you won't easily get that kind of packet capture for free under windows, use wirehshark on linux on a laptop (boot from USB rather than installing it on the laptop), or, use a mac.

 

You can also consider to use an AP as a packet sniffer and send the resulting stream to a any machine running wireshark (windows or otherwise), this procedure will be floating around in the forum and will work well enough to show radio headers.

 

Failing that, you can infer the QAM rates being used, to some extent, by looking into the tx/rx rates being used by the client and referring to the "ht or vht rate table" for the bssid.

 

This approach is not perfect because some rates are the same despite being different MCS and #ss, but it's about as close as you can get using the controller only, but it's good enough to tell you something about expected throughput.

 

relevant commands for the controller (you can find a MCS to #QAM X/Y chart online in various places)

show ap ht-rates <bssid>
show ap vht-rates <bssid>

show ap debug client-stats <mac> | include Mbps show ap debug radio-stats radio X ap-name Y | include Mbps clear ap debug client-stats <mac> clear ap debug radio-stats radio X ap-name Y * where radio 0 is 5 GHz, radio 1 is 2.4 GHz * use the clear to reset the stats, unused rates don't get displayed, ergo you can run a test and then check the "histogram" that was used. * beware SM MIMO Powersave which can cause some clients to turn off a radio and thus spray unexpected rates into the histogram, samsung phones especially

hth.

 

 

Occasional Contributor II

Re: 802.11ac snfifer options and cli output

Thank you. Good input and that is about what i have figured out. Only difference is I'm running Instant so I need commands for that..:)

 

Thanks,

Guru Elite

Re: 802.11ac snfifer options and cli output

http://community.arubanetworks.com/t5/Controller-less-WLANs/How-to-IAP-wireless-packet-capture/ta-p/205035


*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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