I understand that there are network and IP-level mitigations for DDoS attacks, but I'm not clear on how they work in practice.
My hope is that this question and answer will help to frame how the core transit routers handle these attacks, and also how a single client host (be it a proxy or end-device) can handle it, without basically removing it from the Internet.
P.S. I've edited this question to address the "too broad" flag. If this is still "too broad", I'll take it down if this doesn't fit SE's goals. Cheers.