MCS stats mismatch

Just a quick question - ePMP 5ghz sector running 2.5.2, six clients running variously 2.5, 2.5.1 and 2.5.2.

The AP reports 65% of downlink traffic over MCS14, 10% over MCS1.

But all six clients each show more than half of their downlink traffic in MCS1.

The numbers simply don't add up, and I'm trying to figure out why.


Hi.  I don't know if this is the cause of what you're seeing but this is one possibility...

When a radio transmits data, the transmit side knows about all the packet that it has sent. However, if those packets are totally lost in the air for some reason, the receiving side doesn't ever receive them and may have no knowledge of them at all.  So, the sending side may say ''I've sent 53 packets distribted on these MCS's'' and the receiving side may say ''the 27 packets I received were distributed on these MCS's"


That makes some sense, and I'm hoping it's something that innocuous.  Of course I still need to figure out why 6 clients from -46 to -69 are all doing this on that one AP, but my question was strictly about the severe mismatch in the reported stats.  (Three clients run at MCS15 up and down, two run at MCS14 up and down, but when actual traffic is flowing they all seem to drop to MCS1.)


All management traffic is running on MCS1.

Please be aware about that.

Thank you.

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Bingo, that makes sense.  The same Broadcast packet will count once on the AP, but seem to be six times as much (aggregate) at the SM ends, once for each SM.