We have this VDSL2 line at one of our customer sites, which aquired high packet loss from one day to the other ...

we are using a fritzbox 7390 at the site and according to its log there are no problems, also the DSL Information tab does no count a high number of errors ...

Here are the smokeping observations of the link

http://oss.oetiker.ch/smokeping-demo/?displaymode=n;start=2013-01-15%2013:50...

Any hints on getting this fixed.

Thanks to Matthias Herzog for pointing me in the right direction. It seems that 2-3 months ago, AVM has released a new firmware for the Fritz!Box which does (non configurable) rate limiting on ICMP packets.

The worst about this is, that they seem to be looking at the overall number of ICMP packets, not per sender or somethhing like this.

By raising the ping interval in smokeping to 5 seconds, the problem went away ...

cheers tobi