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[jaydub]

Following IDNet moving our connection onto BTw backhaul mid-December last year, we were consistently getting speed test results in the range 73-74Mbps on both single nad multi thread.  Something changed in February this year and we now get nothing greater than 70.5Mbps.

Obviously this maked no practical difference to the use of the connection, but my science/enginrering background makes me want to understand why.

Our FTTC cabinet is the other side of the garden wall, so we sync at 80/20.  I've tried different modem and router combinations, so don't think it is hardware realated.  Uninstalling the AV on the iMac makes no difference.

I know it's a real first world problem, but has anybody any ideas what might have caused this slight degradation?

[dorzb]

Following IDNet moving our connection onto BTw backhaul mid-December last year, we were consistently getting speed test results in the range 73-74Mbps on both single nad multi thread.  Something changed in February this year and we now get nothing greater than 70.5Mbps.

Obviously this maked no practical difference to the use of the connection, but my science/enginrering background makes me want to understand why.

Our FTTC cabinet is the other side of the garden wall, so we sync at 80/20.  I've tried different modem and router combinations, so don't think it is hardware realated.  Uninstalling the AV on the iMac makes no difference.

I know it's a real first world problem, but has anybody any ideas what might have caused this slight degradation?

can you post your line stats?

[jelv]

Could you post a link to a TBB speedtest result please.

Are you tests always wired?

[jaydub]

can you post your line stats?

Code: [Select]

Connection stats

adsl info --stats
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    0
Last initialization procedure status:   0
Max:    Upstream rate = 23280 Kbps, Downstream rate = 87103 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 79987 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):        8.0             6.9
Attn(dB):        6.7             0.0
Pwr(dBm):       -13.2           -13.1

                        VDSL2 framing
                        Bearer 0
MSGc:           18              150
B:              239             236
M:              1               1
T:              23              5
R:              0               16
S:              0.0955          0.3771
L:              20104           5410
D:              1               1
I:              240             255
N:              240             255

                        Counters
                        Bearer 0
OHF:            1248385124              232410
OHFErr:         1773            1458
RS:             0               3640374
RSCorr:         0               7500
RSUnCorr:       0               0

                        Bearer 0
HEC:            6107            0
OCD:            1               0
LCD:            1               0
Total Cells:    4056547819              0
Data Cells:     1684609876              0
Drop Cells:     0
Bit Errors:     0               0

ES:             1351            834
SES:            0               0
UAS:            27              27
AS:             2065022

                        Bearer 0
INP:            0.00            0.00
INPRein:        0.00            0.00
delay:          0               0
PER:            1.65            6.15
OR:             116.09          202.87
AgR:            80103.09        20203.27

Bitswap:        1043/1043               663/663

Total time = 23 days 21 hours 37 min 29 sec
FEC:            0               7500
CRC:            1773            1458
ES:             1351            834
SES:            0               0
UAS:            27              27
LOS:            0               0
LOF:            0               0
LOM:            0               0
Latest 15 minutes time = 7 min 29 sec
FEC:            0               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:            0               0
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Latest 1 day time = 21 hours 37 min 29 sec
FEC:            0               255
CRC:            51              55
ES:             35              32
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Previous 1 day time = 24 hours 0 sec
FEC:            0               342
CRC:            60              65
ES:             41              37
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Since Link time = 23 days 21 hours 37 min 1 sec
FEC:            0               7500
CRC:            1773            1458
ES:             1351            834
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0

Could you post a link to a TBB speedtest result please.

Are you tests always wired?

Test immediately before the change:
https://www.thinkbroadband.com/speedtest/1554233730425780555

And one immediately after:
https://www.thinkbroadband.com/speedtest/1554680005146683655

The (mini) step change was between 2nd & 8th April, not mid-February as I originally posted.

All tests are wired and the tests are very consistent (see attached graph)

[Postal]

Following IDNet moving our connection onto BTw backhaul mid-December last year, we were consistently getting speed test results in the range 73-74Mbps on both single nad multi thread.  Something changed in February this year and we now get nothing greater than 70.5Mbps.

Obviously this maked no practical difference to the use of the connection, but my science/enginrering background makes me want to understand why.

Our FTTC cabinet is the other side of the garden wall, so we sync at 80/20.  I've tried different modem and router combinations, so don't think it is hardware realated.  Uninstalling the AV on the iMac makes no difference.

I know it's a real first world problem, but has anybody any ideas what might have caused this slight degradation?

AFAIK we have always been on a BTw backhaul with IDNet.  We had the same sort of drop at the start of May this year when our sync remained at 79999 while the download speedtests dropped from 72+ to 69+.  Then a week later there was a silent re-connection and the sync dropped to 74963 and download speeds to 64+.  The BTw IP profile was at 74.01 when we sync'd at 79999 and then dropped to 70.61 then 65.62.  IDNet say that the line now has re-transmission high and that BTOR will not do a DLM reset as their systems show that the line is in spec.

I've no idea why the re-transmission high was implemented - there have certainly been no indoor changes so there was presumably some sort of interference outside which has made the systems think the line is unstable.

Not much help to you but it might be a grain of comfort that you are not alone!

[RealAleMadrid]

In the Op's case it isn't related to retransmission high because there is no G.Inp so presumably a very short line to an ECI cab. What does the BT profile say using further diagnostics on the wholesale speed checker? I can't get mine because the checker just hangs and also reports zero upload speed so it's a bit broken!

[Postal]

In the Op's case it isn't related to retransmission high because there is no G.Inp so presumably a very short line to an ECI cab. What does the BT profile say using further diagnostics on the wholesale speed checker? I can't get mine because the checker just hangs and also reports zero upload speed so it's a bit broken!

Currently sync'd at 74083, SNR 3.4.  Tested with wired connection and further diagnostics shows:

Download speed achieved during the test was - 58.79 Mbps
 For your connection, the acceptable range of speeds is 40 Mbps-64.84 Mbps .
 Additional Information:
 IP Profile for your line is - 64.84 Mbps

Upload speed achieved during the test was - 15Mbps
 Additional Information:
 Upstream Rate IP profile on your line is - 20 Mbps

Using the AA speedtest, I am consistently showing between 64 and 65 download (average 64.39) and just over 18 upload (average 18.14).  From the enthusiastic amateur's point of view the AA download looks high when compared with the IP Profile.

[jaydub]

In the Op's case it isn't related to retransmission high because there is no G.Inp so presumably a very short line to an ECI cab. What does the BT profile say using further diagnostics on the wholesale speed checker? I can't get mine because the checker just hangs and also reports zero upload speed so it's a bit broken!

Downstream Test:

Download speedachieved during the test was - 68.78 Mbps
For your connection, the acceptable range of speeds is 40 Mbps-73.77 Mbps .
Additional Information:  IP Profile for your line is - 73.77 Mbps

Upstream Test:

Upload speed achieved during the test was - 14.98Mbps
Additional Information:  Upstream Rate IP profile on your line is - 20 Mbps

We were unable to identify any performance problem with your service at this time.

And yes it is a very short line to an ECI cabinet.  It's the other side of our front garden wall!

[jaydub]

I had IDNet support run a GEA test, which confirmed that my line is on a full 80/20 IP profile (or at least it was on 31st October!)

Profile Name    0.128M-80M Downstream, Error Protection Off - 0.128M-20M Upstream, Error Protection Off
Time Stamp      2019-10-31T09:00:00 

So not sure why the BT Speedtest was reporting an IP Profile of 73.77 Mbps.  Will try running from the test socket when back at home tomorrow to see if that makes any difference.

Not a biggy anyways.  Just trying to understand what is the limiting factor in terms of througput on the TBB speedtest.

[jaydub]

Having done a bit more reading, I think I understand the position a bit better.

The line has a connection profile and the line syncs at a speed of up to the maximum speed of the connection profile.

In my case, the GEA test confirm that I am on a 80/20 Connection Profile:

Profile Name    0.128M-80M Downstream, Error Protection Off - 0.128M-20M Upstream, Error Protection Off

My line syncs at 80:20 so that is aligned to the connection profile.  Good news so far!

According to this Kitz page my IP profile should automatically be 96.8% of the sync speed.  A similar Plusnet post suggests the figure is 96.7%.

This means at worst case my sync speed should be 77344 kbps, not the 73.77 that the BT speedtester is reporting

Additional Information:  IP Profile for your line is - 73.77 Mbps

Why would the IP Profile be below the 96.8/96.7% figure and is there anything that the iSP (IDNet in my case) can do about it?