Just to summarize.
The laptop I name ‘Klystron’ has as one of its problems, that when I simply close the lid, the WiFi looses its connectivity, even though no error messages are displayed, and even though its GUI does not indicate that a new connection ever needed to be negotiated with my router. Yet, when I open the lid, this connectivity – i.e. signal – is reestablished immediately.
Previously, my router was set for 802.11 b/g/n mode, Automatic, and the ‘N Mode’ could not be realized, because my Guest Network was set to a simpler form of encryption than WPA2. At one point in time, I set the Guest Network to WPA2 encryption in a way unified with the main network, and this enabled 802.11n mode for the first time.
Also, I had some success in maintaining the connectivity of the laptop with its lid closed, just by changing the screensaver settings, so that its display was off, 100% of the time the lid was closed.
But then what I discovered, was that the speed with which this laptop was connected, dropped from 802.11n speed to 802.11 b/g speeds, because I had closed the lid.
Because I know that to have a single device on the WiFi that is not at 802.11n speeds, will reduce the connection speed of all my wireless devices to b/g speeds, I next set my router to ‘802.11n mode only’.
This ensured that Klystron was connected at 802.11n speeds again.
But it also brought back the behavior, that this laptop will lose its connectivity, whenever I just close its lid.
This is not due to any power-saving modes being enabled.
A while back, when I set up this laptop for the first time, there was the sporadic behavior, that it could lose its connection while I was busy downloading, with the lid up of course. This problem has since disappeared, but may have gone away for two reasons:
- I have undergone a number of kernel updates. Those kernel updates may have improved the stability of the hardware encryption of my WiFi chipset, which to the best of my knowledge is On.
- I have disabled any use that the laptop may make of IPv6, when connecting to this one router.
Either way, the chipset seems to be stable now. My kernel version is ‘4.4.0-22-generic’.
And while I could set my router back to b/g/n Automatic mode, for the moment I am keeping my eye on the fact, that one slow device, or one laptop with its lid closed, would also drop the speed of my other devices – including my phone, my tablet, and my Sony Web-enabled Blu-Ray player. And so I am keeping my router set to ‘N Only’ for now. ‘Klystron’ will simply have to remain without a WiFi capability, while its lid is closed.