Hi Mikael,
On Feb 25, 2015, at 14:36 , Mikael Abrahamsson <[email protected]> wrote: > On Wed, 25 Feb 2015, Sebastian Moeller wrote: > >> The only argument for ingress shaping on the CPE is that this allows >> the end user to define her own QOS criteria independent of the ISPs wishes. >> Best of both worlds would be user configurable QOS-shaping on the >> slam/bras/whatever… > > As I said before, doing FQ_CODEL in the AR is an expensive proposition for > medium and high speed access. Well a vectoring DSLAM is not too wimpy and needs to do plenty of processing per line, so fq_codel on there should be more finically sane than on a device with more concurrent users, I would guess... > So if this could successfully be pushed to the CPE it would mean it would be > more widely deployed. But there we face the same problem, the wimpy CPEs that ISPs like to distribute do not have enough pomp for shaping a reasonably fast lane, the saving grace might be that end customers can upgrade on their own cost. And I notice a number of specialized home routers appearing on the market targeting people wiling to spend $$ for better behavior under load. > > I am very much aware that this is being done (I have done it myself), but my > question was if someone had actually done this in a lab and found out how > well it works in RRUL tests etc. Not in the lab, no; I have no lab, but I used RRUL iteratively to figure out empirically what shaping percentage I need on my line to keep latency under load in bounds I consider reasonable. In my case DTAG vdsl50 this turned out to be 90% of downlink sync and 95% of uplink sync (but I since learned that DTAG has a BRAS policer that has a lower rate than the VDSL-line, so I guess I was closer to 95% and 99% percent of the BRAS policer, but heaven knows which encapsulation the BRAS accounts for…) So I would guess the collection of cerowrt users should be able to cough up a number of empirical shaping percentages for different link speeds and technologies. Here is my data, the empirically derived shaping values puzzled me until I learned about the BRAS policer. I had expected that the uplink shaper could run almost at 100%, which turned out to be correct if referenced to the BRAS policer and not the vdlx sync. Anyway here is my data, maybe others want to add their’s: Tech downlink_kbps uplink_kbps CPE_shaper sync ISP_policed CPE_shaped sync ISP_policed CPE_shaped overhead_B linklayer VDSL2.vectoring 51390 45559 46178 10047 9460 9500 16 ethernet Best Regards Sebastian > > -- > Mikael Abrahamsson email: [email protected] _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
