How Cloudflare blocked a monumental 7.3 Tbps DDoS attack

A DDoS gets some fraction of the entire internet to attack a single host.

As the internet gets more users and more devices connected, the ratio of DDoS volume to a single connections volume will only get larger.

Is there any kind of solution?

Not a 100% solution but would help greatly if ISPs:

1) performed egress filtering to prevent spoofing arbitrary source addresses

2) temporarily shut off customers that are sending a large volume of malicious traffic

> sending a large volume of malicious traffic

How would an ISP determine egress is malicious? Genuinely curious.