MCS Values

[terrywatson651]

Hi

I carried out some iperf performance tests over a Cisco WLAN.  As part of the tests I recorded the connection speed of the client to the WLC.  Afterwards I noted something unusal.  For many of the 5GHz tests the WLC reproted a connection speed of M9 SS2 on a 40MHz bonded connection.  If I refer to an MCS table I get a value of either 54Mbps or 60Mbps depending on the Guard Interval.  If I am generous and say the throughput is 50% of the connection speed, at best we could expect a throughput of 30Mbps.  However my throughput tests showed download to the client of up to 190Mbps.

I am running 8510 HA Controller Pair on version 8.3.102.0. and most APs connected to were 3702i.

The only answer is that I misinterpreting the speed vlaue as shown in the Controller, do we know if Cisco have there own MCS chart showing the actual speed represented by their M values?  Either that or am I fundamentally misinterpreting something.

Thanks in advance

[michaelblum · Accepted solution]

are you running an 11ac client and AP by any chance.

MCS9 2SS 11ac gives you above 300Mbps. 

MCS9 2SS 11n only gives you the mentioned 54 or 60Mbps

http://www.wlanpros.com/mcs-index-802-11n-802-11ac-chart-3/

[terrywatson651]

Thanks Michael, that makes a lot more sense, yes I was running an 11ac connection.