Question

how to speed up the roaming speed between two aerohive 230?

  • 8 July 2021
  • 2 replies
  • 65 views

Userlevel 2

I deploy two aerohive ap230 on the same floor, here is the result of `show acsp neighor | inc aerohive` and `show acsp`
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AH230(bigroom)#show acsp

Interface Channel select state Primary channel Channel width Power ctrl state Tx power(dbm) Use Last Selection
--------- --------------------- ---------------- ------------- --------------------- ------------- ---------------------
Wifi0 Enable 11 20 Enable 14 Channel:No Power:No
Wifi1 Enable 44 40 Enable 13 Channel:No Power:No

AH230(bigroom)#show acsp neighbor | inc aerohive
Bssid Mode Ssid/Hive Chan Rssi(dBm) Aerohive AP CU CRC STA Channel-width VID NVID
9c5d:1249:2bd4 Access aerohive 1 -75 yes 25 25 1 20 9 9
Bssid Mode Ssid/Hive Chan Rssi(dBm) Aerohive AP CU CRC STA Channel-width VID NVID
4018:b129:26e9 Access aerohive 157 -69 yes 0 0 0 40+ - -
9c5d:1249:2be4 Access aerohive 157 -76 yes 5 12 4 40+ 9 9


AH230(jkzq-core)#show acsp

Interface Channel select state Primary channel Channel width Power ctrl state Tx power(dbm) Use Last Selection
--------- --------------------- ---------------- ------------- --------------------- ------------- ---------------------
Wifi0 Enable 1 20 Enable 14 Channel:No Power:No
Wifi1 Enable 157 40 Enable 14 Channel:No Power:No

AH230(jkzq-core)#show acsp neighbor | inc aerohive
Bssid Mode Ssid/Hive Chan Rssi(dBm) Aerohive AP CU CRC STA Channel-width VID NVID
4018:b129:26d4 Access aerohive 6 -81 yes 31 0 0 20 - -
9c5d:1249:1614 Access aerohive 11 -76 yes 19 94 2 20 9 1
Bssid Mode Ssid/Hive Chan Rssi(dBm) Aerohive AP CU CRC STA Channel-width VID NVID
9c5d:1249:1624 Access aerohive 44 -73 yes 7 84 4 40+ 9 1


---

I walk with android running two tools(termux and wifi魔盒), walk from one ap zone to another ap zone, and rear back. Here are the results:

 

  •  ping

running termux on android, and ping the subnet's gateway

ping result of roaming


it seems there are 3 packets lost when roaming.

 

  • wifi魔盒(Developed by a chinese corp, so I translate the chinese to english)

the result indicate that there is one packet lost when roaming, the latency is huge big: 698ms

wifi魔盒 roaming result


it seems there are 5 packets lost when roaming

question:

  1. what utilitis how do you guys use to evaluated roaming?
  2. how to tune the roaming speed up?

2 replies

Userlevel 7

Hello, I ran this question by our XIQ engineers and they requested that you open a case for this so we can dig in a bit deeper with you to see what can be done to improve the roaming speeds.

Userlevel 2

After google around, I found a useful blog:
https://www.sniffwifi.com/2018/08/roam-if-you-want-to-as-long-as-your.html

I change the channel width from 40Mhz to 20Mhz, the roaming peroid change dramatically from Hundreds to dozens, but I don't understand how it works. here are some piece from that post:


My experience, on the other hand, is that design cannot overcome some of the issues that arise when 40 or 80 MHz wide channels are used in high mobility environments.  Even with an "optimal" design, an AP or client device could stubbornly transmit using higher-than-expected data rates, thus causing data frame failures even with a "good" SNR.  When the SNR signal has to be at double (for 40 MHz wide channels) or quadruple (for 80 MHz) the level in order for frames to be successful, the problem of stubbornly high data rates is exacerbated.  Or, client devices may be "sticky", and stay connected to a low SNR signal AP, even though the client has moved close to a higher SNR signal AP.

Obviously, I have not seen every Wi-Fi environment.  From the enterprise Wi-Fi environments I have seen, 20 MHz wide channels helps roaming.  The reality is that low SNR instances may occur when people are on the move, and the exclusion of 40 or 80 MHz wide channels can prevent that movement from causing short term Wi-Fi connectivity outages.
 

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