5GHz radio disappears after a while (Fritzbox 4040)

Installing and Using OpenWrt Network and Wireless Configuration
1

Setup: Fritzbox 4040, running 19.07.7, upgraded to 21.02.0 without preserving config.

Before the upgrade, both radios were working fine for extended periods of time, say a couple of months. After the upgrade, I reviewed the configs, reconfigured as needed, all seemed fine.

Turns out, however, that after a while the 5GHz radio signal disappears. If I reboot, it comes back immediately. It may also come back after a while, just by waiting, meanwhile nothing suspicious in the logs:

Mon Oct  4 06:56:45 2021 daemon.notice hostapd: wlan1: interface state DFS->ENABLED
Mon Oct  4 06:56:45 2021 daemon.notice hostapd: wlan1: AP-ENABLED

(and a few connection-related entries when the signal was present... key point: last status is "ENABLED")

Has anyone observed something like this? Any ideas? To reiterate: no such funny disappearing acts with the older release.

2

Apparently I have lots of radar conflicts, but I am unconvinced because:

  1. the previous version had none
  2. the main SSID is stil online and part of the corresponding bridge, whereas "guest" and "iot" have gone dark

Seems like it doesn't recover, is that to be expected?

Excerpts from the log:

Oct  4 23:50:14 router-casa-andrea hostapd: wlan1: DFS-RADAR-DETECTED freq=5620 ht_enabled=0 chan_offset=0 chan_width=3 cf1=5610 cf2=0
Oct  4 23:50:14 router-casa-andrea hostapd: wlan1: AP-DISABLED
Oct  4 23:50:14 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1 wasn't started
Oct  4 23:50:14 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1-1 wasn't started
Oct  4 23:50:14 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1-2 wasn't started
Oct  4 23:50:14 router-casa-andrea hostapd: nl80211: deinit ifname=wlan1 disabled_11b_rates=0
Oct  4 23:50:14 router-casa-andrea kernel: [60908.496613] device wlan1 left promiscuous mode
Oct  4 23:50:14 router-casa-andrea kernel: [60908.497974] br-casa: port 3(wlan1) entered disabled state
Oct  4 23:50:14 router-casa-andrea hostapd: wlan1: interface state HT_SCAN->DISABLED
Oct  4 23:50:16 router-casa-andrea kernel: [60910.390860] br-casa: port 3(wlan1) entered blocking state
Oct  4 23:50:16 router-casa-andrea kernel: [60910.390902] br-casa: port 3(wlan1) entered disabled state
Oct  4 23:50:16 router-casa-andrea hostapd: wlan1: interface state DISABLED->COUNTRY_UPDATE
Oct  4 23:50:16 router-casa-andrea hostapd: wlan1: interface state COUNTRY_UPDATE->HT_SCAN
Oct  4 23:50:16 router-casa-andrea hostapd: wlan1: DFS-RADAR-DETECTED freq=5620 ht_enabled=0 chan_offset=0 chan_width=3 cf1=5610 cf2=0
Oct  4 23:50:16 router-casa-andrea hostapd: wlan1: AP-DISABLED
Oct  4 23:50:16 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1 wasn't started
Oct  4 23:50:16 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1-1 wasn't started
Oct  4 23:50:16 router-casa-andrea kernel: [60910.395735] device wlan1 entered promiscuous mode
Oct  4 23:50:16 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1-2 wasn't started
Oct  4 23:50:16 router-casa-andrea hostapd: nl80211: deinit ifname=wlan1 disabled_11b_rates=0
Oct  4 23:50:16 router-casa-andrea kernel: [60910.445214] device wlan1 left promiscuous mode
Oct  4 23:50:16 router-casa-andrea kernel: [60910.445390] br-casa: port 3(wlan1) entered disabled state
Oct  4 23:50:16 router-casa-andrea hostapd: wlan1: interface state HT_SCAN->DISABLED
Oct  4 23:50:18 router-casa-andrea kernel: [60912.371838] br-casa: port 3(wlan1) entered blocking state
Oct  4 23:50:18 router-casa-andrea kernel: [60912.371883] br-casa: port 3(wlan1) entered disabled state
Oct  4 23:50:18 router-casa-andrea hostapd: wlan1: interface state DISABLED->COUNTRY_UPDATE
Oct  4 23:50:18 router-casa-andrea hostapd: wlan1: interface state COUNTRY_UPDATE->HT_SCAN
Oct  4 23:50:18 router-casa-andrea kernel: [60912.376775] device wlan1 entered promiscuous mode
Oct  4 23:50:18 router-casa-andrea hostapd: wlan1: DFS-RADAR-DETECTED freq=5620 ht_enabled=0 chan_offset=0 chan_width=3 cf1=5610 cf2=0
Oct  4 23:50:18 router-casa-andrea hostapd: wlan1: AP-DISABLED
Oct  4 23:50:18 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1 wasn't started
Oct  4 23:50:18 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1-1 wasn't started
Oct  4 23:50:18 router-casa-andrea hostapd: hostapd_free_hapd_data: Interface wlan1-2 wasn't started
Oct  4 23:50:18 router-casa-andrea hostapd: nl80211: deinit ifname=wlan1 disabled_11b_rates=0
Oct  4 23:50:18 router-casa-andrea kernel: [60912.446719] device wlan1 left promiscuous mode
Oct  4 23:50:18 router-casa-andrea kernel: [60912.448080] br-casa: port 3(wlan1) entered disabled state
Oct  4 23:50:18 router-casa-andrea hostapd: wlan1: interface state HT_SCAN->DISABLED
Oct  4 23:50:20 router-casa-andrea kernel: [60914.360451] br-casa: port 3(wlan1) entered blocking state
Oct  4 23:50:20 router-casa-andrea kernel: [60914.360499] br-casa: port 3(wlan1) entered disabled state
Oct  4 23:50:20 router-casa-andrea hostapd: wlan1: interface state DISABLED->COUNTRY_UPDATE
Oct  4 23:50:20 router-casa-andrea hostapd: wlan1: interface state COUNTRY_UPDATE->HT_SCAN
Oct  4 23:50:20 router-casa-andrea kernel: [60914.365399] device wlan1 entered promiscuous mode
Oct  4 23:50:20 router-casa-andrea hostapd: wlan1: interface state HT_SCAN->DFS
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: DFS-NOP-FINISHED freq=5580 ht_enabled=0 chan_offset=0 chan_width=0 cf1=5580 cf2=0
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: interface state DFS->DFS
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: DFS-NOP-FINISHED freq=5600 ht_enabled=0 chan_offset=0 chan_width=0 cf1=5600 cf2=0
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: interface state DFS->DFS
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: DFS-NOP-FINISHED freq=5620 ht_enabled=0 chan_offset=0 chan_width=0 cf1=5620 cf2=0
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: interface state DFS->DFS
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: DFS-NOP-FINISHED freq=5640 ht_enabled=0 chan_offset=0 chan_width=0 cf1=5640 cf2=0
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: interface state DFS->DFS
Oct  5 00:20:28 router-casa-andrea hostapd: wlan1: DFS-CAC-START freq=5620 chan=124 sec_chan=1, width=0, seg0=122, seg1=0, cac_time=60s
3

Moved from channel 124 to 36, hoping to see that it makes a difference.
Edit: no more radar events, therefore stable.

Question now is: what broke? :smiley:
(meaning: with 19.07 it would after some time recover on its own... with 21.02.0 it won't)

1 Like
4

Interesting point, I dont remember having had problems on my FritzBox 4040 with 19.07, but its a while since using it. But Channel 36 on 5Ghz works just fine :slight_smile: