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Author Topic: Upstream test results long-term variation  (Read 2352 times)

Weaver

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Upstream test results long-term variation
« on: March 11, 2021, 06:51:54 PM »

When I measure upstream combined link effective speed with speedtest.aa.net.uk I get a lot of statistical noise, in that upstream results vary wildly in a group of back-to-back tests, for reasons unknown. I always take the max and discard the rest. Long-term, over a timescale of weeks or months, I see a really large variation, sometimes with max values in a test group that are even up to 50% higher, consistently in a test group, and at other times this variation is absent. There seem to be ‘high rate seasons’ or ‘periods’ during which all test groups will give a high max result, and then these high group max results go away. A high season result is 1.50-1.65; a low season result is 1.0-1.2.

I just have no clue why this is happening. The upstream sync rates do not change. It’s not associated with cold weather. I recently got a record high upstream of 1.65 Mbps, again from speedtest.aa.net.uk, and now a week or so later this high result has gone away, yet the temperature has not changed significantly. In any case wouldn’t a change in temperature have to cause a change in sync rate for there to be any effect?

The sync rates are currently:
  #1: down 3194 kbps, up 570 kbps
  #2: down 3030 kbps, up 528 kbps
  #3: down 2913 kbps, up 396 kbps
  #4: down 3290 kbps, up 576 kbps
Line 3 upstream is always rubbish; lines 1 and 4 are pretty good although I have seen figures over 600k on occasion.

What am I missing? How can the upstream test figures vary like this? Some weirdness in the tester?

And remember that I always do a group of tests and take only the max, so as to rule out the reducing effects of any alien competing traffic either at my end or into the speed tester. And I sometimes do speed tests in the early hours, although I suppose backups could be running, but the ‘take the max only’ rule excludes those bad results.
« Last Edit: March 11, 2021, 08:34:30 PM by Weaver »
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burakkucat

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Re: Upstream test results long-term variation
« Reply #1 on: March 11, 2021, 08:16:23 PM »

In any case wouldn’t a change in temperature have to cause a change in sync rate for there to be any effect?

Yes, exactly.

Quote
What am I missing? How can the upstream test figures vary like this? Some weirdness in the tester?

Three questions --> three answers:

[1] & [2] (I do not know.)2

[3] I regard all throughput speed testers as weird and only ever consider the synchronisation speed of a circuit.
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Weaver

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Re: Upstream test results long-term variation
« Reply #2 on: March 11, 2021, 08:36:20 PM »

I need to keep a more careful track of sync rates for starters, just in case I’m being really stupid and missing something.
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tubaman

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Re: Upstream test results long-term variation
« Reply #3 on: March 12, 2021, 08:01:11 AM »

I've just been trying speedtest.aa.net.uk on my line and I'm wondering how accurate it is. My VDSL Retx High connection is currently synced at 46473/7816 and AA's speed test has just given my speeds as 44.7/7.91 Mbps. I don't believe such high speeds should be possible with my sync rate (unless I'm missing something). Ookla speed test gave me 40.5/7.2 which seems far more realistic.
 :)

Code: [Select]
> xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    4
Last initialization procedure status:   0
Max:    Upstream rate = 7816 Kbps, Downstream rate = 45852 Kbps
Bearer: 0, Upstream rate = 7816 Kbps, Downstream rate = 46473 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State:       L0
Mode:                   VDSL2 Annex B
VDSL2 Profile:          Profile 17a
TPS-TC:                 PTM Mode(0x0)
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        2.3             5.2
Attn(dB):        26.3            0.0
Pwr(dBm):        12.0            6.4

                        VDSL2 framing
                        Bearer 0
MSGc:           -6              26
B:              227             239
M:              1               1
T:              0               41
R:              10              0
S:              0.0000          0.9756
L:              12202           1968
D:              4               1
I:              238             120
N:              238             240
Q:              4               0
V:              0               0
RxQueue:                112             0
TxQueue:                28              0
G.INP Framing:          18              0
G.INP lookback:         28              0
RRC bits:               0               24
                        Bearer 1
MSGc:           122             -6
B:              0               0
M:              2               0
T:              2               0
R:              16              0
S:              8.0000          0.0000
L:              32              0
D:              1               0
I:              32              0
N:              32              0
Q:              0               0
V:              0               0
RxQueue:                0               0
TxQueue:                0               0
G.INP Framing:          0               0
G.INP lookback:         0               0
RRC bits:               0               0

                        Counters
                        Bearer 0
OHF:            0               1415456
OHFErr:         1208            1094
RS:             3201237868              2803133
RSCorr:         466836372               0
RSUnCorr:       0               0
                        Bearer 1
OHF:            143936747               0
OHFErr:         2               0
RS:             1151493478              0
RSCorr:         3289            0
RSUnCorr:       2               0

                        Retransmit Counters
rtx_tx:         43618319                0
rtx_c:          27683880                0
rtx_uc:         320264          0

                        G.INP Counters
LEFTRS:         7383            0
minEFTR:        46479           0
errFreeBits:    3271869095              0

                        Bearer 0
HEC:            0               0
OCD:            0               0
LCD:            0               0
Total Cells:    270973507               0
Data Cells:     1108737199              0
Drop Cells:     0
Bit Errors:     0               0

                        Bearer 1
HEC:            0               0
OCD:            0               0
LCD:            0               0
Total Cells:    0               0
Data Cells:     0               0
Drop Cells:     0
Bit Errors:     0               0

ES:             879             1485
SES:            67              4
UAS:            137             91
AS:             2312635

                        Bearer 0
INP:            51.00           0.00
INPRein:        1.00            0.00
delay:          0               0
PER:            0.00            10.03
OR:             0.01            25.50
AgR:            46575.30        7841.36

                        Bearer 1
INP:            2.00            0.00
INPRein:        2.00            0.00
delay:          0               0
PER:            16.06           0.01
OR:             63.75           0.01
AgR:            63.75   0.01

Bitswap:        1246127/1246132         24744/24752

Total time = 39 days 20 hours 57 min 20 sec
FEC:            1051594432              0
CRC:            4929            1647
ES:             879             1485
SES:            67              4
UAS:            137             91
LOS:            1               0
LOF:            7               0
LOM:            36              0
Latest 15 minutes time = 12 min 20 sec
FEC:            118989          0
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Previous 15 minutes time = 15 min 0 sec
FEC:            248033          0
CRC:            1               0
ES:             1               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Latest 1 day time = 20 hours 57 min 20 sec
FEC:            16156547                0
CRC:            39              53
ES:             32              51
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Previous 1 day time = 24 hours 0 sec
FEC:            22442403                0
CRC:            42              36
ES:             30              32
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Since Link time = 26 days 18 hours 23 min 53 sec
FEC:            466836372               0
CRC:            1208            1094
ES:             630             1030
SES:            9               3
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
 >
« Last Edit: March 12, 2021, 08:40:18 AM by tubaman »
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j0hn

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Re: Upstream test results long-term variation
« Reply #4 on: March 12, 2021, 01:04:20 PM »

It's been discussed before but the AA speed test (and the LibreSpeed test it is based on) often gives results that are above what are possible from a line.
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burakkucat

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Re: Upstream test results long-term variation
« Reply #5 on: March 12, 2021, 05:35:12 PM »

It's been discussed before but the AA speed test (and the LibreSpeed test it is based on) often gives results that are above what are possible from a line.

b*cat nods in agreement. That tester is deliberately inflating the values. Basically it's just junk. For your own sanity, do not use it.
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Alex Atkin UK

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Re: Upstream test results long-term variation
« Reply #6 on: March 12, 2021, 06:35:46 PM »

b*cat nods in agreement. That tester is deliberately inflating the values. Basically it's just junk. For your own sanity, do not use it.

That's interesting as I have a local copy I use on the LAN and a copy on my VPS and its always seemed very accurate, for downstream at least.

ALL testers in my experience are hit and miss with upstream, not sure why.
« Last Edit: March 12, 2021, 06:37:49 PM by Alex Atkin UK »
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