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To me this is a very interesting topic. How devices join and roam on a network is key to its successful operation. I am a big fan of Smart-RF but Smart-RF does not replace good RF-design. Smart RF takes a good design and optimises it for the here and now.
So why on a “Roaming Assist” thread am I talking about RF design? Well it’s simple; if there is not enough time for a device to roam to a neighbouring AP then the roam will fail (too little RF). If the RF power is too high the client will stick to the AP, even if the RF-Quality is poor. If you set static power and channels you can optimise the solution while you are completing the post installation survey. This is great when the environment does not change.
So let’s look at what we have been discussing - High Density Designs:
Interestingly most high-density designs only operate in a high-density mode for a relatively short period of time. People that are 90% water have an irritating tendency to absorbing some of the RF power! If the TX power is fixed then we can do nothing to counter this problem. Smart-RF will adapt, indeed if you look at the smart RF logs you can see this happening, as more people arrive TX power is slowly increased and as people leave the power is reduced.
In addition to smart RF In WiNG we have an RFQ index, this varies from 0 (no information) to 5 which is Excellent.
Use the command:
show wireless client statistics rf on
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Retry AVG : Average retransmissions per packet
ERRORS : Error Rate of rx errors and retries over good packet per second
Q-INDEX : RF Quality Index, higher value means better quality
(I) : RF matrix index where 0,1,2,3,4,5 maps to
(II) N/A, 1) Poor, 2) Fair, 3) Average, 4) Good, 5) Excellent
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MAC SIGNAL NOISE SNR TX-RATE RX-RATE RETRY ERRORS Q-INDEX RETRY
(dbm)(I) (dbm) db(I) (Mbps)(I) (Mbps)(I) AVG (pps) (I) (%)(I)
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50-DC-E7-88-33-B7 -60(4) -96 36(5) 72(5) 65(5) 0.00 0 4 60.34(1)
D8-31-34-0B-04-9A -73(3) -99 26(4) 96(4) 81(4) 0.75 0 3 40.12(1)
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Total number of wireless clients displayed: 2
This is great to see how the client is performing on your network
Below is a smart RF-policy for US using only Non-DFS channels, note the US region has additional Non-DFS channels in unii band 3
smart-rf-policy STORES
sensitivity custom
assignable-power 5GHz min 14
assignable-power 2.4GHz min 8
channel-list 5GHz 36,40,44,48,149,153,157,161,165
channel-width 5GHz 20MHz
smart-ocs-monitoring sample-count 5GHz 10
smart-ocs-monitoring sample-count 2.4GHz 15
smart-ocs-monitoring extended-scan-frequency 2.4GHz 0
coverage-hole-recovery snr-threshold 5GHz 10
coverage-hole-recovery snr-threshold 2.4GHz 10
neighbor-recovery dynamic-sampling
This is the Channel list we normally use for Stores amended for Etsi regions
channel-list 5GHz 36,40,44,48,52,56,60,64.
If you are doing high density solution you could look at using all the channels
channel-list 5GHz 36,40,44,48,52,56,60,64,100,104,108,112,116,120,124,128,132,136,140,149,
Please minimise the number of SSID’s, only use 20Mhz Channels and remove the lower data rates.