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. 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. 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 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. Regards, Roland _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
