"Bless, Roland (TM)" <roland.bl...@kit.edu> writes: > Hi Luca, > > Am 28.11.18 um 11:48 schrieb Luca Muscariello: > >> And for BBR, I would say that one thing is the design principles another >> is the implementations >> and we better distinguish between them. The key design principles are >> all valid. > > While the goal is certainly right to operate around the optimal point > where the buffer is nearly empty, BBR's model is only valid from either > the viewpoint of the bottleneck or that of a single sender.
I think I agree with this, from my own experimental data. > > In BBR, one of the key design principle is to observe the > achieved delivery rate. One assumption in BBRv1 is that if the delivery > rate can still be increased, then the bottleneck isn't saturated. This > doesn't necessarily hold if you have multiple BBR flows present at the > bottleneck. > Every BBR flow can (nearly always) increase its delivery rate while > probing: it will simply decrease other flows' shares. This is not > an _implementation_ issue of BBRv1 and has been explained in section III > of our BBR evaluation paper. Haven't re-read it yet. > > This section shows also that BBRv1 will (by concept) increase its amount > of inflight data to the maximum of 2 * estimated_BDP if multiple flows > are present. A BBR sender could also use packet loss or RTT increase as Carnage! > indicators that it is probably operating right from the optimal > point, but this is not done in BBRv1. > BBRv2 will be thus an improvement over BBRv1 in several ways. I really really really want a sane response to ecn in bbr. > > Regards, > Roland > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat