On Thu, 29 Aug 2019 at 23:10, <[email protected]> wrote: > All this time watching the thread I'm thinking if it's just coincidence that > in some cases no matter how good the hash value is the available buckets > skew the balancing. (and I guess that's why three are knobs to shift the > hash around.
Obviously there is no perfect solution, but alarm bells should ring if you notice pattern when there is imbalance, such as closely grouped flows. With ideal diffusion the pattern would be random any 5tuple is equally likely to collide with any other 5tuple. With CRC it seems some 5tuples are far more likely to collide with some other 5tuples, and closely group, high volume traffic naturally occurs in very typical network scenarios. Like CDN network internal traffic or SP VOD distribution etc. Bear in mind solution NOK owner found for his problem, adding completely static set of input bits! Which does support (or add confirmation bias at least:) to the explanation that the hash has poor diffusion quality. -- ++ytti _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
