I've used 14.04 until last week and did a fresh install of 18.04. To be clear, the disk with my home folders was not changed and remounted after the install.
However, since then my wifi connection is unstable as hell, i.e., randomly disconnects with no obvious pattern at all. Since I do a lot of ssh tunneled remote work this is quiet annoying.
Also the ping to the router is often unreasonably high, jumping form ~1ms to ~250ms.
After a disconnect (ping to router is not successful) I have to restart network-manager manually to reconnect.
I emphasize that other devices in the same wireless network do not suffer from this phenomenon and with 14.04 I did not have this problem.
journalctl around the time of a disconnect:
Mai 16 07:50:59 home wpa_supplicant: wlx08bd438912c4: WPA: Group rekeying completed with 30:91:8f:03:c8:f9 [GTK=TKIP] Mai 16 08:00:59 home wpa_supplicant: wlx08bd438912c4: WPA: Group rekeying completed with 30:91:8f:03:c8:f9 [GTK=TKIP] Mai 16 08:03:38 home systemd: Started Run anacron jobs. Mai 16 08:03:38 home anacron: Anacron 2.3 started on 2018-05-16 Mai 16 08:03:38 home anacron: Normal exit (0 jobs run) Mai 16 08:10:59 home wpa_supplicant: wlx08bd438912c4: WPA: Group rekeying completed with 30:91:8f:03:c8:f9 [GTK=TKIP] Mai 16 08:11:15 home NetworkManager: <info> [1526451075.8675] manager: NetworkManager state is now CONNECTED_SITE Mai 16 08:11:15 home dbus-daemon: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.13' (uid=0 pid=975 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined") Mai 16 08:11:15 home whoopsie: [08:11:15] offline Mai 16 08:11:15 home systemd: Starting Network Manager Script Dispatcher Service... Mai 16 08:11:15 home dbus-daemon: [system] Successfully activated service 'org.freedesktop.nm_dispatcher' Mai 16 08:11:15 home systemd: Started Network Manager Script Dispatcher Service. Mai 16 08:11:15 home nm-dispatcher: req:1 'connectivity-change': new request (1 scripts) Mai 16 08:11:15 home nm-dispatcher: req:1 'connectivity-change': start running ordered scripts... Mai 16 08:11:26 home whoopsie: [08:11:26] Cannot reach: https://daisy.ubuntu.com
NetGear, Inc. WNA1100 Wireless-N 150 [Atheros AR9271]
wlx08bd438912c4 IEEE 802.11 ESSID:"A1-03C8F9" Mode:Managed Frequency:2.412 GHz Access Point: 30:91:8F:03:C8:F9 Bit Rate=72.2 Mb/s Tx-Power=20 dBm Retry short limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=52/70 Signal level=-58 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:9 Invalid misc:409 Missed beacon:0 lo no wireless extensions. enp3s0 no wireless extensions.
[connection] wifi.powersave = 2
Most of the problems connected to wifi I found in the web are connected to suspending or power management of wifi adapter. I think neither of those is the cause here. For me it looks as if network-manager randomly crashes without logging the cause... but I'm really no network expert :D
As suggested I disabled usb-auto-suspend by blacklisting the wifi adapter.
This seems to improve stability as I had just 2 disconnects during several hours. However, the remaining disconnects where accommodated by the following
error message in
wlx08bd438912c4: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-38 noise=9999 txrate=58500
After the disconnects i had to restart network-manager to reestablish the connection. Can it be that for some reason the connection is lost for a very short period (due to a drop in signal quality) and network-manager fails to automatically reconnect? If so was network-manager configured differently in 14.04?