Hmm, this is an interesting one. I`m not sure who did this or how they did it. I can`t accuse any country of being responsible for this attack but I can share some ideas on how they did it. I have 2 ideas for this problem, and my first idea is the country has placed a filter on pipes going from the main ISP. I`m not sure how they would do this, and I`m pretty sure this is impossible. But keep in mind these are just ideas. Furthermore, my seccond idea is that the country responsible tracked the pipe traffic and then sent many packets of data. Adding on to my 2nd point, doing this would crash the ISP because it would probably exceed the pipes maximum limit. In conclusion, there are many ways that people could do this and we have yet to find out who could do this.
Regards,
Nexus Rudolph