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Standard User deleted
(deleted) Wed 22-Apr-20 21:36:27
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Re: 3db SNR - DLM Parameters?


[re: paulb100] [link to this post]
 
Pity you haven't provided any evidence to support your post. Smells to me like much of the misinformation and lies that are being posted at this time. Have your speeds dropped, are streams buffering? If not get on and enjoy what you have.
Standard User ian72
(eat-sleep-adslguide) Thu 23-Apr-20 09:55:44
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Re: 3db SNR - DLM Parameters?


[re: deleted] [link to this post]
 
I have worked in IT for many years and we have a number of frontline support staff who tell users similar sorts of things - despite the fact that they are untrue - the frontline support staff decide themselves what is causing issues with no detailed knowledge of what is actually happening in the servers, networks, etc at the core. I would always treat these sorts of comments with a very large pinch of salt.

EDIT : Spelling mistake that messed with the meaning

Edited by ian72 (Thu 23-Apr-20 14:53:22)

Standard User candlerb
(experienced) Thu 23-Apr-20 10:17:39
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Re: 3db SNR - DLM Parameters?


[re: ian72] [link to this post]
 
In general, I've found Openreach engineers on the ground are very friendly and helpful but not always knowledgeable outside their narrow training.

A few years ago, I had a guy come to my property when my FTTC had dropped from ~30M to ~20M. He came and plugged in his tester, checked wiring to the cabinet, swapped faceplate etc (and eventually I got my 30M back). However he insisted that with me being 900m from the cabinet, I ought to be getting the maximum 80Mbps.

He had to drop back later with the correct faceplate, so I showed him a graph of expected VDSL speed versus distance.

I guess his expectations were based on the fall-off of characteristics of ADSL - although where I am, I don't think I'd get the full 24M on ADSL either.


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Standard User adslmax
(knowledge is power) Thu 23-Apr-20 22:55:41
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Re: 3db SNR - DLM Parameters?


[re: BLaZiNgSPEED] [link to this post]
 
I am very lucky man indeed. My FTTC always stay as 79999k/19999k sync rate even the line max rate has drop to 83137k (spring/summer time) but around 93200k (autumn/winter season) since 2014 but I have no idea if my cabinet is 100% capacity full?

My latest stats as of now:

Max: Upstream rate = 24118 Kbps, Downstream rate = 83137 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79999 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): 6.5 14.7
Attn(dB): 11.5 0.0
Pwr(dBm): 12.4 -0.4

VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 2.5 13.1 20.2 N/A N/A 6.9 15.7 25.9
Signal Attenuation(dB): 2.5 12.6 19.6 N/A N/A 8.9 15.5 25.9
SNR Margin(dB): 14.9 14.7 14.7 N/A N/A 6.6 6.3 6.6
TX Power(dBm): -15.2 -30.0 -0.7 N/A N/A 8.0 7.9 7.0

Edited by adslmax (Thu 23-Apr-20 22:57:08)

Standard User candlerb
(experienced) Fri 24-Apr-20 07:14:31
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Re: 3db SNR - DLM Parameters?


[re: adslmax] [link to this post]
 
In reply to a post by adslmax:
I am very lucky man indeed. My FTTC always stay as 79999k/19999k sync rate even the line max rate has drop to 83137k (spring/summer time) but around 93200k (autumn/winter season) since 2014 but I have no idea if my cabinet is 100% capacity full?


When there are no free ports, this shows up as "Wait list" when you do an address check on the wholesale checker (but not a phone number check). At least, that's what I saw for my cabinet a year or so back until they put an expansion pod on it.
Standard User BLaZiNgSPEED
(member) Fri 24-Apr-20 12:43:02
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Re: 3db SNR - DLM Parameters?


[re: adslmax] [link to this post]
 
@adslmax: Indeed you are very lucky. Your line attenuation is very low at only 11.5dB!

This suggests that you have a very short line, probably less than 50 meters to your street cabinet! My line attenuation is 17.9dB at around 320 meters to the nearest cabinet.

I'm guessing in your case even if there is a fairly high capacity on your cabinet, because you are so close to it, crosstalk has a smaller impact on your speeds.

My upstream noise margin is slightly higher than yours at 15.10dB. My downstream was sitting between 6.0-6.8dB but in recent few weeks it has dropped to 4.10dB despite no impact on the connection, this may well coincide with the corona virus period where the SNR may have slightly been impacted due to overload of customers using the internet more as they are out of work. This wasn't the case prior to the corona virus lock down but as long as the connection is stable that's all that matters.

As for crosstalk, I believe it depends really whether you live in an individual house or residential block! I have a suspicion that crosstalk has a greater impact on high rise residential buildings where the cabinet is overstuffed with too many customers taking FTTC particularly as with my case we don't have Virgin Media here or another altnet provider.

But some other council homes that are also connected with the same cabinet are on the verge of getting Hyperoptic. If you have other people having altnet providers they may put less pressure on the FTTC cabinet, thus giving you a better connection!

My connection speeds and stats in general also remain the same, as the 30 day reboot in my case does not impact connection speed as DLM does not interpret the connection drop as line noise or interference related, it is simply router programming with TalkTalk. At least I know I won't have that issue in future with a different router.
Standard User adslmax
(knowledge is power) Fri 24-Apr-20 12:55:31
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Re: 3db SNR - DLM Parameters?


[re: BLaZiNgSPEED] [link to this post]
 
In reply to a post by BLaZiNgSPEED:
@adslmax: Indeed you are very lucky. Your line attenuation is very low at only 11.5dB!

This suggests that you have a very short line, probably less than 50 meters to your street cabinet! My line attenuation is 17.9dB at around 320 meters to the nearest cabinet.


I wish it was less than 50 meters! Actually my line is approx 253 meters or 277 yards from my nearest cabinet. No chance of less than 50 meters because if it was then my BTw checker estimated for G.fast would be 330/50 easily but not the case as it was estimated at 220/32

Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Handback
Threshold(Mbps) WBC FTTC Availability Date WBC SOGEA Availability Date Left in Jumper
High Low High Low
VDSL Range A (Clean) 80 67.2 20 19 62 Available Available --
VDSL Range B (Impacted) 80 65.8 20 19 59.7 Available Available --
G.fast Range A (Clean) 220.8 166.9 32.1 13.8 144.6 Available Available --
G.fast Range B (Impacted) 177.9 122.2 21.7 10.4 109.2 Available Available --

Edited by adslmax (Fri 24-Apr-20 13:03:01)

Standard User adslmax
(knowledge is power) Fri 24-Apr-20 12:58:24
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Re: 3db SNR - DLM Parameters?


[re: candlerb] [link to this post]
 
In reply to a post by candlerb:
When there are no free ports, this shows up as "Wait list" when you do an address check on the wholesale checker (but not a phone number check). At least, that's what I saw for my cabinet a year or so back until they put an expansion pod on it.


Yeah my cabinet has been on the waiting lists five times before become available but my fibre cabinet is not yet on expansion pod on it.
Standard User BLaZiNgSPEED
(member) Fri 24-Apr-20 13:59:39
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Re: 3db SNR - DLM Parameters?


[re: adslmax] [link to this post]
 
In reply to a post by adslmax:
In reply to a post by BLaZiNgSPEED:
@adslmax: Indeed you are very lucky. Your line attenuation is very low at only 11.5dB!

This suggests that you have a very short line, probably less than 50 meters to your street cabinet! My line attenuation is 17.9dB at around 320 meters to the nearest cabinet.


I wish it was less than 50 meters! Actually my line is approx 253 meters or 277 yards from my nearest cabinet. No chance of less than 50 meters because if it was then my BTw checker estimated for G.fast would be 330/50 easily but not the case as it was estimated at 220/32

Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Handback
Threshold(Mbps) WBC FTTC Availability Date WBC SOGEA Availability Date Left in Jumper
High Low High Low
VDSL Range A (Clean) 80 67.2 20 19 62 Available Available --
VDSL Range B (Impacted) 80 65.8 20 19 59.7 Available Available --
G.fast Range A (Clean) 220.8 166.9 32.1 13.8 144.6 Available Available --
G.fast Range B (Impacted) 177.9 122.2 21.7 10.4 109.2 Available Available --
This is interesting because my line attenuation in router stats is 17.9dB
Yet these are my results for my post code Bishopsgate Cabinet 20

Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Handback
Threshold(Mbps) WBC FTTC Availability Date WBC SOGEA Availability Date
High Low High Low
VDSL Range A (Clean) 80 68.2 20 19 62.1 Available Available
VDSL Range B (Impacted) 80 64.8 20 19 56.6 Available Available

My speed estimates are actually pretty much the same as yours, but you have 11.5dB line attenuation and I have 17.9dB, this is a massive difference for speed stats that are pretty much identical! I don't understand those differences. I did a google search and another user has 11dB line attenuation similar to yours and he says it is 30 meters to his cabinet which is why I assumed yours is that much as well.

At least one measurement seems accurate from our comparison is that my cabinet is roughly 300 meters and yours is 253 meters and that is why our speed estimates for FTTC are pretty much identical.
Standard User adslmax
(knowledge is power) Fri 24-Apr-20 18:13:12
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Re: 3db SNR - DLM Parameters?


[re: BLaZiNgSPEED] [link to this post]
 
In reply to a post by BLaZiNgSPEED:
I did a google search and another user has 11dB line attenuation similar to yours and he says it is 30 meters to his cabinet which is why I assumed yours is that much as well.

At least one measurement seems accurate from our comparison is that my cabinet is roughly 300 meters and yours is 253 meters and that is why our speed estimates for FTTC are pretty much identical.


Do u have any source link to that person who has 11dB line attenuation. Last time I talk to BT Openreach via echat they say my line length to the cabinet are 135m away but OPenreach engineer who install my FTTC in 2014 say my line distance to the street cabinet are 250m away. Plusnet GEA test say my line length are 243.6m.

Two next doors of mine in a terraced house got 330/50 for G.fast, next door left of mine got 237/35 for G.fast and other next door right to mine got 237/35 for G.fast.

bkehoe compared to adslmax for VDSL2 to GFAST below:

VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 3.3 12.3 19.1 N/A N/A 7.1 15.2 24.5
Signal Attenuation(dB): 3.3 11.6 18.2 N/A N/A 7.9 15.1 24.5
SNR Margin(dB): 15.4 15.1 15.0 N/A N/A 6.6 6.6 6.8
TX Power(dBm):-15.6 -31.1 -1.5 N/A N/A 9.3 7.8 7.0

VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 2.5 13.0 20.0 N/A N/A 6.8 15.5 25.8
Signal Attenuation(dB): 2.5 12.1 19.0 N/A N/A 8.8 15.4 25.7
SNR Margin(dB): 16.8 15.2 15.2 N/A N/A 8.3 8.2 8.2
TX Power(dBm):-15.1 -30.2 -0.7 N/A N/A 8.1 7.9 7.0

Data rate: 159.443 Mbps / 29.399 Mbps (160/30 G.fast)
Maximum data rate: 397.693 Mbps / 74.580 Mbps (330/50 G.fast)
Noise margin: 19.6 / 20.9
Line attenuation: 26.7 / 0.0
Signal attenuation: 26.7 / 0.0

reO for VDSL2 to GFAST below:

VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 3.7 9.6 13.8 N/A N/A 5.5 11.4 17.7
Signal Attenuation(dB): 3.7 9.1 12.9 N/A N/A 6.5 11.3 17.7
SNR Margin(dB): 15.9 15.1 15.6 N/A N/A 6.4 6.5 6.6
TX Power(dBm):-21.0 -33.7 -6.7 N/A N/A 10.0 7.7 7.0

xDSL Port Details: Upstream Downstream
Line Rate: 330.614 Mbps 50.345 Mbps (330/50 G.fast)
Actual Net Data Rate: 329.907 Mbps 50.016 Mbps (330/50 G.fast)
Trellis Coding: ON ON
SNR Margin: 8.2 dB 9.0 dB
Actual Delay: 0 ms 0 ms
Transmit Power: 0.0 dBm 4.1 dBm
Receive Power: 3.0 dBm 4.7 dBm
Actual INP: 550.0 symbols 535.0 symbols
Attainable Net Data Rate: 406.832 Mbps 67.552 Mbps

Edited by adslmax (Fri 24-Apr-20 18:18:30)

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