thanks And yes Dave, some logged tests (if we pre-arrange what day, and you tell me the UTCs) using this particular server would be good, I'll be in touch on that, I have to setup a capture that just isolates your IP.
So Is there anything different, or detectable, on the server side for such a fully congestion aware connection, but no congestion is encountered? So on upload phase, I can see CE marks come in, but during download phase there is nothing interesting to detect and log? On Wed, Apr 20, 2016 at 10:43 PM, Jonathan Morton <chromati...@gmail.com> wrote: > >> On 20 Apr, 2016, at 09:06, jb <jus...@dslr.net> wrote: >> >> So this particular snap from the first 200 packets of a download there >> are poor RTTs but it also picked up the IP ecn_capable flag (but not >> the IP ecn congestion flag) and it picked up the TCP ece and cwr flags >> on. > > The TCP ECE and CWR flags are always set during ECN negotiation. If there > are no CE marks subsequently, they will not appear again once the data phase > begins. You can therefore distinguish between ECN capability of the host and > the network. > > For a “download” test, your sender will see ECE flags inbound and generate > CWR flags outbound *during the data phase* only if there is an ECN aware AQM > on the path at the bottleneck. It will not see the CE marks themselves, as > those are only present between the bottleneck and the receiver. > > For an “upload" test, your receiver will see the inbound CE marks from an AQM > active on the bottleneck, respond to them with ECE flags, and receive CWR > flags in reply. Again, only during the data phase. > > - Jonathan Morton > _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
