Not ideal, sure, but if it’s only for the SYN (as you seem to indicate), splitting the flow shouldn’t have material performance degradation?
> On Nov 13, 2019, at 11:51, Toke Høiland-Jørgensen <t...@toke.dk> wrote: > > > >> On 13 November 2019 17:20:18 CET, Matt Corallo <netad...@as397444.net> wrote: >> This sounds like a bug on Cloudflare’s end (cause trying to do anycast >> TCP is... out of spec to say the least), not a bug in ECN/ECMP. > > Even without anycast, an ECMP shouldn't hash on the ECN bits. Doing so will > split the flow over multiple paths; avoiding that is the whole point of doing > the flow-based hashing in the first place. > > Anycast "only" turns a potential degradation of TCP performance into a hard > failure... :) > > -Toke
