[Rpm] [ippm] Preliminary measurement comparison of "Working Latency" metrics
Dave Taht
dave.taht at gmail.com
Tue Nov 1 00:21:39 EDT 2022
Dear Al:
OK, I took your udpst tool for a spin.
NICE! 120k binary (I STILL work on machines with only 4MB of flash),
good feature set, VERY fast, and in very brief testing, seemed
to be accurate in the starlink case, though it's hard to tell with
them as the rate changes every 15s.
I filed a couple bug reports on trivial stuff:
https://github.com/BroadbandForum/obudpst/issues/8
(Adding diffserv and ecn washing or marking detection would be a nice
feature to have)
Aside from the sheer joy coming from the "it compiles! and runs!"
phase I haven't looked much further.
I left a copy running on one of my starlink testbeds -
fremont.starlink.taht.net - if anyone wants to try it. It's
instrumented with netperf, flent, irtt, iperf2 (not quite the latest
version from bob, but close), and now udpst, and good to about a gbit.
nice tool!
Has anyone here played with crusader? ( https://github.com/Zoxc/crusader )
On Mon, Oct 31, 2022 at 4:30 PM Dave Taht <dave.taht at gmail.com> wrote:
>
> On Mon, Oct 31, 2022 at 1:41 PM MORTON JR., AL <acmorton at att.com> wrote:
>
> > > have you tried irtt? (https://github.com/heistp/irtt )
> > I have not. Seems like a reasonable tool for UDP testing. The feature I didn't like in my scan of the documentation is the use of Inter-packet delay variation (IPDV) instead of packet delay variation (PDV): variation from the minimum (or reference) delay. The morbidly curious can find my analysis in RFC 5481: https://datatracker.ietf.org/doc/html/rfc5481
>
> irtt was meant to simulate high speed voip and one day
> videoconferencing. Please inspect the json output
> for other metrics. Due to OS limits it is typically only accurate to a
> 3ms interval. One thing it does admirably is begin to expose the
> sordid sump of L2 behaviors in 4g, 5g, wifi, and other wireless
> technologies, as well as request/grant systems like cable and gpon,
> especially when otherwise idle.
>
> Here is a highres plot of starlink's behaviors from last year:
> https://forum.openwrt.org/t/cake-w-adaptive-bandwidth-historic/108848/3238
>
> clearly showing them "optimizing for bandwidth" and changing next sat
> hop, and about a 40ms interval of buffering between these switches.
> I'd published elsewhere, if anyone cares, a preliminary study of what
> starlink's default behaviors did to cubic and BBR...
>
> >
> > irtt's use of IPDV means that the results won’t compare with UDPST, and possibly networkQuality. But I may give it a try anyway...
>
> The more the merrier! Someday the "right" metrics will arrive.
>
> As a side note, this paper focuses on RAN uplink latency
> https://dl.ifip.org/db/conf/itc/itc2021/1570740615.pdf which I think
> is a major barrier to most forms of 5G actually achieving good
> performance in a FPS game, if it is true for more RANs. I'd like more
> to be testing uplink latencies idle and with load, on all
> technologies.
>
> >
> > thanks again, Dave.
> > Al
> >
> > > -----Original Message-----
> > > From: Dave Taht <dave.taht at gmail.com>
> > > Sent: Monday, October 31, 2022 12:52 PM
> > > To: MORTON JR., AL <acmorton at att.com>
> > > Cc: ippm at ietf.org; Rpm <rpm at lists.bufferbloat.net>
> > > Subject: Re: [ippm] Preliminary measurement comparison of "Working Latency"
> > > metrics
> > >
> > > Thank you very much for the steer to RFC9097. I'd completely missed that.
> > >
> > > On Mon, Oct 31, 2022 at 9:04 AM MORTON JR., AL <acmorton at att.com> wrote:
> > > >
> > > > (astute readers may have guessed that I pressed "send" too soon on previous
> > > message...)
> > > >
> > > > I also conducted upstream tests this time, here are the results:
> > > > (capacity in Mbps, delays in ms, h and m are RPM categories, High and
> > > Medium)
> > > >
> > > > Net Qual UDPST (RFC9097) Ookla
> > > > UpCap RPM DelLD DelMin UpCap RTTmin RTTrange UpCap
> > > Ping(no load)
> > > > 34 1821 h 33ms 11ms 23 (42) 28 0-252 22 8
> > > > 22 281 m 214ms 8ms 27 (52) 25 5-248 22 8
> > > > 22 290 m 207ms 8ms 27 (55) 28 0-253 22 9
> > > > 21 330 m 182ms 11ms 23 (44) 28 0-255 22 7
> > > > 22 334 m 180ms 9ms 33 (56) 25 0-255 22 9
> > > >
> > > > The Upstream capacity measurements reflect an interesting feature that we
> > > can reliably and repeatably measure with UDPST. The first ~3 seconds of
> > > upstream data experience a "turbo mode" of ~50Mbps. UDPST displays this
> > > behavior in its 1 second sub-interval measurements and has a bimodal reporting
> > > option that divides the complete measurement interval in two time intervals to
> > > report an initial (turbo) max capacity and a steady-state max capacity for the
> > > later intervals. The UDPST capacity results present both measurements: steady-
> > > state first.
> > >
> > > Certainly we can expect bi-model distributions from many ISPs, as, for
> > > one thing, the "speedboost" concept remains popular, except that it's
> > > misnamed, as it should be called speed-subtract or speed-lose. Worse,
> > > it is often configured "sneakily", in that it doesn't kick in for the
> > > typical observed duration of the test, for some, they cut the
> > > available bandwidth about 20s in, others, 1 or 5 minutes.
> > >
> > > One of my biggest issues with the rpm spec so far is that it should,
> > > at least, sometimes, run randomly longer than the overly short
> > > interval it runs for and the tools also allow for manual override of length.
> > >
> > > we caught a lot of tomfoolery with flent's rrul test running by default for
> > > 1m.
> > >
> > > Also, AQMs on the path can take a while to find the optimal drop or mark rate.
> > >
> > > >
> > > > The capacity processing in networkQuality and Ookla appear to report the
> > > steady-state result.
> > >
> > > Ookla used to basically report the last result. Also it's not a good
> > > indicator of web traffic behavior at all, watching the curve
> > > go up much more slowly in their test on say, fiber 2ms, vs starlink,
> > > (40ms)....
> > >
> > > So adding another mode - how quickly is peak bandwidth actually
> > > reached, would be nice.
> > >
> > > I haven't poked into the current iteration of the goresponsiveness
> > > test at all: https://urldefense.com/v3/__https://github.com/network-
> > > quality/goresponsiveness__;!!BhdT!giGhURYxqguQCyB3NT8rE0vADdzxcQ2eCzfS4NRMsdvb
> > > K2bOqw0uMPbFeJ7PxzxTc48iQFubYTxxmyA$ it
> > > would be good to try collecting more statistics and histograms and
> > > methods of analyzing the data in that libre-source version.
> > >
> > > How does networkQuality compare vs a vs your tool vs a vs goresponsiveness?
> > >
> > > >I watched the upstream capacity measurements on the Ookla app, and could
> > > easily see the initial rise to 40-50Mbps, then the drop to ~22Mbps for most of
> > > the test which determined the final result.
> > >
> > > I tend to get upset when I see ookla's new test flash a peak result in
> > > the seconds and then settle on some lower number somehow.
> > > So far as I know they are only sampling the latency every 250ms.
> > >
> > > >
> > > > The working latency is about 200ms in networkQuality and about 280ms as
> > > measured by UDPST (RFC9097). Note that the networkQuality minimum delay is
> > > ~20ms lower than the UDPST RTTmin, so this accounts for some of the difference
> > > in working latency. Also, we used the very dynamic Type C load
> > > adjustment/search algorithm in UDPST during all of this testing, which could
> > > explain the higher working latency to some degree.
> > > >
> > > > So, it's worth noting that the measurements needed for assessing working
> > > latency/responsiveness are available in the UDPST utility, and that the UDPST
> > > measurements are conducted on UDP transport (used by a growing fraction of
> > > Internet traffic).
> > >
> > > Thx, didn't know of this work til now!
> > >
> > > have you tried irtt?
> > >
> > > >
> > > > comments welcome of course,
> > > > Al
> > > >
> > > > > -----Original Message-----
> > > > > From: ippm <ippm-bounces at ietf.org> On Behalf Of MORTON JR., AL
> > > > > Sent: Sunday, October 30, 2022 8:09 PM
> > > > > To: ippm at ietf.org
> > > > > Subject: Re: [ippm] Preliminary measurement comparison of "Working
> > > Latency"
> > > > > metrics
> > > > >
> > > > >
> > > > > Hi again RPM friends and IPPM'ers,
> > > > >
> > > > > As promised, I repeated the tests shared last week, this time using both
> > > the
> > > > > verbose (-v) and sequential (-s) dwn/up test options of networkQuality. I
> > > > > followed Sebastian's calculations as well.
> > > > >
> > > > > Working Latency & Capacity Summary
> > > > >
> > > > > Net Qual UDPST Ookla
> > > > > DnCap RPM DelLD DelMin DnCap RTTmin RTTrange DnCap
> > > > > Ping(no load)
> > > > > 885 916 m 66ms 8ms 970 28 0-20 940 8
> > > > > 888 1355 h 44ms 8ms 966 28 0-23 940 8
> > > > > 891 1109 h 54ms 8ms 968 27 0-19 940 9
> > > > > 887 1141 h 53ms 11ms 966 27 0-18 937 7
> > > > > 884 1151 h 52ms 9ms 968 28 0-20 937 9
> > > > >
> > > > > With the sequential test option, I noticed that networkQuality achieved
> > > nearly
> > > > > the maximum capacity reported almost immediately at the start of a test.
> > > > > However, the reported capacities are low by about 60Mbps, especially when
> > > > > compared to the Ookla TCP measurements.
> > > > >
> > > > > The loaded delay (DelLD) is similar to the UDPST RTTmin + (the high end of
> > > the
> > > > > RTTrange), for example 54ms compared to (27+19=46). Most of the
> > > networkQuality
> > > > > RPM measurements were categorized as "High". There doesn't seem to be much
> > > > > buffering in the downstream direction.
> > > > >
> > > > >
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: ippm <ippm-bounces at ietf.org> On Behalf Of MORTON JR., AL
> > > > > > Sent: Monday, October 24, 2022 6:36 PM
> > > > > > To: ippm at ietf.org
> > > > > > Subject: [ippm] Preliminary measurement comparison of "Working Latency"
> > > > > > metrics
> > > > > >
> > > > > >
> > > > > > Hi RPM friends and IPPM'ers,
> > > > > >
> > > > > > I was wondering what a comparison of some of the "working latency"
> > > metrics
> > > > > > would look like, so I ran some tests using a service on DOCSIS 3.1, with
> > > the
> > > > > > downlink provisioned for 1Gbps.
> > > > > >
> > > > > > I intended to run apple's networkQuality, UDPST (RFC9097), and Ookla
> > > > > Speedtest
> > > > > > with as similar connectivity as possible (but we know that the traffic
> > > will
> > > > > > diverge to different servers and we can't change that aspect).
> > > > > >
> > > > > > Here's a quick summary of yesterday's results:
> > > > > >
> > > > > > Working Latency & Capacity Summary
> > > > > >
> > > > > > Net Qual UDPST Ookla
> > > > > > DnCap RPM DnCap RTTmin RTTVarRnge DnCap Ping(no
> > > load)
> > > > > > 878 62 970 28 0-19 941 6
> > > > > > 891 92 970 27 0-20 940 7
> > > > > > 891 120 966 28 0-22 937 9
> > > > > > 890 112 970 28 0-21 940 8
> > > > > > 903 70 970 28 0-16 935 9
> > > > > >
> > > > > > Note: all RPM values were categorized as Low.
> > > > > >
> > > > > > networkQuality downstream capacities are always on the low side compared
> > > to
> > > > > > others. We would expect about 940Mbps for TCP, and that's mostly what
> > > Ookla
> > > > > > achieved. I think that a longer test duration might be needed to achieve
> > > the
> > > > > > actual 1Gbps capacity with networkQuality; intermediate values observed
> > > were
> > > > > > certainly headed in the right direction. (I recently upgraded to
> > > Monterey
> > > > > 12.6
> > > > > > on my MacBook, so should have the latest version.)
> > > > > >
> > > > > > Also, as Sebastian Moeller's message to the list reminded me, I should
> > > have
> > > > > > run the tests with the -v option to help with comparisons. I'll repeat
> > > this
> > > > > > test when I can make time.
> > > > > >
> > > > > > The UDPST measurements of RTTmin (minimum RTT observed during the test)
> > > and
> > > > > > the range of variation above the minimum (RTTVarRnge) add-up to very
> > > > > > reasonable responsiveness IMO, so I'm not clear why RPM graded this
> > > access
> > > > > and
> > > > > > path as "Low". The UDPST server I'm using is in NJ, and I'm in Chicago
> > > > > > conducting tests, so the minimum 28ms is typical. UDPST measurements
> > > were
> > > > > run
> > > > > > on an Ubuntu VM in my MacBook.
> > > > > >
> > > > > > The big disappointment was that the Ookla desktop app I updated over the
> > > > > > weekend did not include the new responsiveness metric! I included the
> > > ping
> > > > > > results anyway, and it was clearly using a server in the nearby area.
> > > > > >
> > > > > > So, I have some more work to do, but I hope this is interesting-enough
> > > to
> > > > > > start some comparison discussions, and bring-out some suggestions.
> > > > > >
> > > > > > happy testing all,
> > > > > > Al
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > _______________________________________________
> > > > > > ippm mailing list
> > > > > > ippm at ietf.org
> > > > > >
> > > > >
> > > https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/ippm__;!!Bhd
> > > > > >
> > > > >
> > > T!hd5MvMQw5eiICQbsfoNaZBUS38yP4YIodBvz1kV5VsX_cGIugVnz5iIkNqi6fRfIQzWef_xKqg4$
> > > > >
> > > > > _______________________________________________
> > > > > ippm mailing list
> > > > > ippm at ietf.org
> > > > >
> > > https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/ippm__;!!Bhd
> > > > > T!g-
> > > FsktB_l9MMSGNUge6FXDkL1npaKtKcyDtWLcTZGpCunxNNCcTImH8YjC9eUT262Wd8q1EBpiw$
> > > >
> > > > _______________________________________________
> > > > ippm mailing list
> > > > ippm at ietf.org
> > > >
> > > https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/ippm__;!!Bhd
> > > T!giGhURYxqguQCyB3NT8rE0vADdzxcQ2eCzfS4NRMsdvbK2bOqw0uMPbFeJ7PxzxTc48iQFub_gMs
> > > KXU$
> > >
> > >
> > >
> > > --
> > > This song goes out to all the folk that thought Stadia would work:
> > > https://urldefense.com/v3/__https://www.linkedin.com/posts/dtaht_the-mushroom-
> > > song-activity-6981366665607352320-
> > > FXtz__;!!BhdT!giGhURYxqguQCyB3NT8rE0vADdzxcQ2eCzfS4NRMsdvbK2bOqw0uMPbFeJ7PxzxT
> > > c48iQFub34zz4iE$
> > > Dave Täht CEO, TekLibre, LLC
>
>
>
> --
> This song goes out to all the folk that thought Stadia would work:
> https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981366665607352320-FXtz
> Dave Täht CEO, TekLibre, LLC
--
This song goes out to all the folk that thought Stadia would work:
https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981366665607352320-FXtz
Dave Täht CEO, TekLibre, LLC
More information about the Rpm
mailing list