Flowspec is the current method of signaling unwanted connectivity to a DDOS clearance center.
The FRR project has also a basic support for flowspec:
https://github.com/FRRouting/frr/blob/master/doc/user/flowspec.rst
It would be a huge benefit for VyOS if it would be able to receive flowspec information and allow the filtering for those.
There is also a nice presentation here:
https://docs.google.com/presentation/d/1ekQygUAG5yvQ3wWUyrw4Wcag0LgmbW1kV02IWcU4iUg/
Regards
Markus