On Wed, 2 Sep 2020, Warren Kumari wrote:
The root issue here is that the *publicc* RFO is incomplete / unclear. Something something flowspec something, blocked flowspec, no more something does indeed explain that something bad happened, but not what caused the lack of withdraws / cascading churn. As with many interesting outages, I suspect that we will never get the full story, and "Something bad happened, we fixed it and now it's all better and will never happen ever again, trust us..." seems to be the new normal for public postmortems...
It's possible Level3's people don't fully understand what happened or that the "bad flowspec rule" causing BGP sessions to repeatedly flap network wide triggered software bugs on their routers. You've never seen rpd stuck at 100% CPU for hours or an MX960 advertise history routes to external peers, even after the internal session that had advertised the route to it has been cleared?
To quote Zaphod Beeblebrox "Listen, three eyes, don't you try to outweird me. I get stranger things than you free with my breakfast cereal."
Kick a BGP implementation hard enough, and weird shit is likely to happen. ---------------------------------------------------------------------- Jon Lewis, MCP :) | I route StackPath, Sr. Neteng | therefore you are _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
