Yes, network operators (should) participate in centralized black hole services like UTRS[1]. If you can identify the specific IPs that are under attack you make a BGP announcement to other participating networks asking them to drop traffic to that IP within their networks.
As a participant you can avoid paying to send outbound attack traffic, and also identify attack sources within your own network.
- You need to identify the traffic to be filtered and the post states: "Due to always different destinations (IPs, ports, packet size) (..)"
- You need to maintain some agreement with a large number of ISPs
- You need to maintain some gossiping infrastructure to these ISPs
- ISPs may not care about your DDoS attack