Edit: there are some news coming from FranceIx. Here is the link to an official post with the explanation.
In the afternoon of Monday, August 18, many of us have encountered problems in communications to France. In France there is the main OVH datacenter, a provider of hosting and colocation also very popular in Italy: for about an hour, their servers were unreachable by many connectivity providers.
The inaccessibility of OVH is the symptom of the problem, but it has nothing to do with the cause. The real problem has occurred to FranceIX, the main French NAP, that is the point at which the leading providers of connectivity and services interconnect between them. Similar NAP are also present in Italy: the most important is the MIX, but there are many others like the NaMeX and the VSIX.
Well, apparently, at FranceIX yesterday there was a problem of broadcast traffic between afferents, presumably a DDOS: technicians at FranceIX instead of analyzing in detail what was happening, they thought to turn off everything!
Within a few seconds, it has gone from about 200 Gbit of exchanged traffic to zero, without any warning, so afferents have had to find alternative solutions to not remain isolated.
It ‘s true that after the reboot the problem was no longer up again, but this is definitely not the correct modus operandi you would expect from professionals: the “brutal reboot” has caused more than an hour’s block and, more important, it has erased any data useful for the problem analysis, which would have allowed them to study how to prevent it from happening again in the future.
So, either it was a problem caused by FranceIX like an incorrect configuration of network devices that then they are no longer able to remedy, then an hard reset has brought everything to the previous working configuration, or, if were an attack, we do not have the assurance that the problem does will not be again in the future.