wifi roaming

Now I am working wifi roaming, using standard 80211mac and user space wpa_supplicant.
I want to achieve this:
when current associated RSSI is below threshold, then automatically roam to new best RSSI AP
I am not sure currently mac80211 support this.
(1) how to set this RSSI threshold
(2) my assumption to achieve this, there are 2 approach.
A: wpa_supplicant with background scanning, I test this, but the performance is not so good, when roam to new AP, scan takes around 140ms per channel, I check the mac80211/scan, it seems using passive scanning, how to change to active scanning? If so, I am assuming it will decease scanning time.
B: is it possible for mac80211/ath10k driver, when associated RSSI below threshold, it automatically roams to new best RSSI ap, no need user space wpa_supplicant involved. I think user space wpa_supplicant doesn't have neighbor information, while mac80211 should have.

Hello, chrisliu, & welcome to LQ.

Have a look at this: How_To_Ask_a_Question

You give us none of the information we need to answer your query, like

• What distribution are you using?
• Have you Networkmanager or init scripts controlling the wifi?
• I presume it's wifi. What chip does it use?
• Are you working in X or without X?
• Do the different access points use the same password or different ones?

Hi business_kid, thanks for your reply, sorry for missed important information.
[*]What distribution are you using?
embedded Linux Yocto, not using normal distribution.[*]Have you Networkmanager or init scripts controlling the wifi?
no Networkmanager or init scripts, for client side, using wpa_supplicant to control wifi.[*]I presume it's wifi. What chip does it use?
QCA986x/988x 802.11ac[*]Are you working in X or without X?
without X[*]Do the different access points use the same password or different ones?
same password

Originally Posted by business_kid Hello, chrisliu, & welcome to LQ. Have a look at this: How_To_Ask_a_Question You give us none of the information we need to answer your query, like What distribution are you using? Have you Networkmanager or init scripts controlling the wifi? I presume it's wifi. What chip does it use? Are you working in X or without X? Do the different access points use the same password or different ones?

Right.

Depending on the host setup, either your dhcp server or your wpa_supplicant might be dropping out, or both. Pore over the man pages of your wpa_supplicant & dhcp client, and see which requires a restart, or if both do. If one router assigned a particular IP, another router may not talk to it.

My guess is: If there was only one central dhcp server, all traffic would get sent to that, and your assigned IP would be good anywhere in the building. That's obviously not the case, so something else has been done. Check your IP regularly while investigating. If you ever see 169.254.x.x as your IP, your lease ran out when you had NO signal. So your dhcpcd client assigned that IP. It means the signal is patchy.

Whatever your dhcp client, there's options for rebinding your lease. If they will work, use them. Otherwise make sure to get rid of lease records in places like /var/lib/somewhere/somewhere. I'd try that first.

Also, your lease lasts a preset time, then gets checked. It's possible if you leave everything alone until the lease runs out, the box will reconnect. Try it. It might save messing.

in my setup, there is no dhcp, all IPs are static
for wifi client, which is running wpa_supplicant. The client can roam between 2 APs, but it is very slow.
it seems it only roam to new AP until lose beacon, or signal is very very weak. I want to make client automatically roam to new AP when the received RSSI is below certain threshold value, for example, -65dBm.
currently I am suing wpa_suppliant bgscan, it seems not working as I expect.

Originally Posted by business_kid Right. Depending on the host setup, either your dhcp server or your wpa_supplicant might be dropping out, or both. Pore over the man pages of your wpa_supplicant & dhcp client, and see which requires a restart, or if both do. If one router assigned a particular IP, another router may not talk to it. My guess is: If there was only one central dhcp server, all traffic would get sent to that, and your assigned IP would be good anywhere in the building. That's obviously not the case, so something else has been done. Check your IP regularly while investigating. If you ever see 169.254.x.x as your IP, your lease ran out when you had NO signal. So your dhcpcd client assigned that IP. It means the signal is patchy. Whatever your dhcp client, there's options for rebinding your lease. If they will work, use them. Otherwise make sure to get rid of lease records in places like /var/lib/somewhere/somewhere. I'd try that first. Also, your lease lasts a preset time, then gets checked. It's possible if you leave everything alone until the lease runs out, the box will reconnect. Try it. It might save messing.

Unless youi have been given a fixed IP, how do you connect?