This weekend went my Internet (VDLS) down. The DSL part was still up, but the IPv4 connectivity (over PPPoE) was down. When I checked the Fritzbox (7340) I saw that the DLS had 'trained' on ~100Mbps down and ~30Mbps up. Connection speeds I could only dream of......
Trying to re-establish the IPv4 connection I restarted the DSL modem. Upon reboot, it trained on about 70Mbps download and 30Mbps upload, and the PPPoE tunnel for IPv4 established nicely..... for about 5 minutes.
It turned out that the DSL connection tried to get a better connection, and got it. So starting off at 70Mbps, it could establish a 74Mbps a couple of seconds later, and 75Mbps a bit later after that, and so on, and so on. During this time the PPPoE connection worked like a charm. Until the DSL reached the magical 100Mbps rate. That's when the PPPoE (and the actual IPv4 connection to the Internet) failed.
I tried resetting the modem a couple of times, but every time the same weird behavior.
Checking my ISP revealed that there were some issues on several locations in the Netherlands AND there was some work on the DSL network scheduled this weekend. This could all be related to my problem, so I asked. The ISP said that my problem was not related to any existing problems, so i had to log a support ticket (on Whit Sunday - *sigh*).
Not having the patience to wait for an answer I tried to get an older firmware. The one I was running was version 06.25 (some lab version), and the last stable version I could find on the Internet (by using 4g Internet) was version 06.06.
Installing the lower version meant that the DSL modem goes back to its factory defaults, so I saved the config to file for future reference, and started the downgrade. After the downgrade and the reconfiguration the DSL and PPPoE was stable at around 55Mbps download and 24Mbps upload.
After a couple of hours, Internet was down again.....
It turned out the the software had been upgraded (remotely) by the service provider, and the original v06.25 software was reinstalled. This resulted in the same problem. So I had the challenge to prevent those remote initiated upgrades.
Thankfully, the v06.06 software has a way of preventing this upgrading feature hidden in the web GUI of the Fritzbox, but this is NOT visible by default. It's hidden in the 'Advanced' settings..
To enable the 'Advanced' view of the GUI click on the 'View: Standard' link at the bottom of the GUI.
When the view is set to 'Advanced', go to 'Internet' -> 'Account Information' -> 'Provider Services', and disable the update settings.
After this, the IPv4 connection stayed up. The IPv6 connection doesn't come up, but I can live with that for the next couple of days, since I don't actively use that connection at the moment. All I can do now is wait for my new modem to arrive.
I'm not sure what this does for your IP Telephony (VoIP) or IPTV services from your provider, since I don't have any of those. Could be that those stay down as well.