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Mesh Status Neighbor Info

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Mesh Status Neighbor Info

I'm confused by some of the information displayed in mesh status on the newer firmware.  The current docs are not explicitly clear and the help on the node is not either.

We have LQ, NLQ, SNR, Quality, TxMbps, and Distance

LQ and NLQ is understood, this is the % packets that do not have to be retransmitted in both directions.
SNR now has two numbers XX/XX so I assume this is SNR from   your node/the other node ??
What is Quality?  How is this determined?  When you set LQM to a quality to accept, I thought that was the LQ but is it LQ or "Quality"?
TxMbps and Distance are understood.

Thanks,  Ed
w6bi's picture
Ed, TxMbps is misunderstood by most people.  It's not throughput.  From the Help File:

Transmitted Mbps (TxMbps) is calculated with the formula (TxMbps = rate x EWMA) where rate is the 802.11 data rate in use by the transmitter and EWMA is the Exponentially Weighted Moving Average or the current time-weighted chance that a packet at this rate will reach the remote station. If no traffic is being routed to the neighbor, this value may be '0' until data is available to measure and determine the optimal rate. For further details: Rate Control Algorithm

So basically it's the modulation rate (MCS0-14) times the percentage of packets making it through without being retransmitted.

There's a good explanation of the modulation rates in the middle of the Wikipedia article on 802.11n:

I'll have to get back to you on Quality - there's nothing in the help file about it :-/

Orv W6BI
Quality metric definition
From the online documentation:

Quality is the Link Quality calculated as the moving average of (total sent packets) divided by (total sent packets plus retransmissions), expressed as a percent. For example, if the node had to send every packet twice for it to be successfully received, the link quality would be 50%. An additional penalty is subtracted if the neighbor node is unpingable, which is explained in the Advanced Configuration section under “Ping Penalty”. Be aware that the LQ/NLQ metrics are calculated differently, so there may not be a perfect alignment when comparing the two quality metrics.
[Tim KN6PLV created this metric as part of LQM]

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