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Protecting my upstream speed - turning off aggressive downstream SNR...?

Bobsta
Grafter
Posts: 61
Thanks: 6
Registered: ‎23-12-2011

Protecting my upstream speed - turning off aggressive downstream SNR...?

Hi folks,

 

I'm in the unfortunate position of living over a kilometre away from my cabinet, meaning my connection has a lot of copper to deal with. The biggest problem with this is the lack of upstream bandwidth. When you have less than 2Mbps upstream normal day-to-day activities like making VoIP phone calls (S4B, WiFi calling from mobiles) and Zoom/WebEx sessions start becoming problematic - mainly as other actives such as sending emails and devices backing up or syncing to cloud services (iCloud, OneDrive, Dropbox, etc.) hog all the available bandwidth and send latency through the roof.

 

So - in summary, upstream bandwidth is *really* important. (and it bugs me that the whole industry is focused on downstream bandwidth when it really shouldn't - but let's not digress) 

 

My issue - how can I "protect" what little upstream bandwidth I have?

 

When our village was first FTTC-enabled I was one of the first to sign up and could get a reliable 2Mbps upstream (and around 20Mbps down). However this year I've watched my upstream sync speed drop month by month. I'm assuming this is due to increased take-up of FTTC in the village and therefore an increase in crosstalk. But I also believe it's been impacted by the rollout of G.INP and a focus on maximising downstream bandwidth with lower target SNRs (3.0dB instead of 6.0dB). My upstream sync has gone from 2Mbps to around 1.35Mbps in 12 months.

 

I left BT last month (19 Nov) to switch back to Plusnet - because I like you guys more, and you're cheaper. On switchover day my line sync speed jumped up quite a bit, and on day two I was getting a much more healthy 1.7Mbps upstream. Admittedly my downstream sync wasn't so great - but as I say, I don't care about that. This is what I was getting:

Stats recorded 21 Nov 2018 05:54:31

DSLAM type / SW version:	BDCM:0xb12d (177.45) / v0xb12d
Modem/router firmware:  	AnnexA version - A2pv6C038m.d24j
DSL mode:               	VDSL2 Profile 17a
Status:                 	Showtime
Uptime:                 	 20 hours 8 min 33 sec
Resyncs:                	4 (since 18 Nov 2018 22:37:15)
			
				Downstream	Upstream
Line attenuation (dB):  	29.6		0.0
Signal attenuation (dB):	Not available on VDSL2		
Connection speed (kbps):	17611		1705
SNR margin (dB):        	5.9		5.5
Power (dBm):            	8.9		4.5
Interleave depth:       	293		1
INP:                    	3.00		0
G.INP:                  	Not enabled		Not enabled
Vectoring status:       	5 (VECT_UNCONFIGURED)		

RSCorr/RS (%):          	0.3997		0.0000
RSUnCorr/RS (%):        	0.0002		0.0000
ES/hour:                	5.75		5.75

 

A few days later it'd shifted to:

Stats recorded 24 Nov 2018 10:17:30

DSLAM type / SW version:	BDCM:0xb12d (177.45) / v0xb12d
Modem/router firmware:  	AnnexA version - A2pv6C038m.d24j
DSL mode:               	VDSL2 Profile 17a
Status:                 	Showtime
Uptime:                 	 3 hours 43 min 28 sec
Resyncs:                	8 (since 18 Nov 2018 22:37:15)
			
				Downstream	Upstream
Line attenuation (dB):  	29.5		0.0
Signal attenuation (dB):	Not available on VDSL2		
Connection speed (kbps):	20243		1677
SNR margin (dB):        	6.0		5.6
Power (dBm):            	9.0		4.7
Interleave depth:       	4		1
INP:                    	50.00		0
G.INP:                  	Enabled		Not enabled
Vectoring status:       	5 (VECT_UNCONFIGURED)		

RSCorr/RS (%):          	0.2111		0.0000
RSUnCorr/RS (%):        	0.0000		0.0000
ES/hour:                	0.97		2.52

G.INP now enabled but downstream SNR still at 6.0.

 

 

Then a few days later things start going downhill - as downstream SNR reduces (and connection speed increases) I start losing more of my upstream:

Stats recorded 28 Nov 2018 02:45:30

DSLAM type / SW version:	BDCM:0xb12d (177.45) / v0xb12d
Modem/router firmware:  	AnnexA version - A2pv6C038m.d24j
DSL mode:               	VDSL2 Profile 17a
Status:                 	Showtime
Uptime:                 	1 day 20 hours 2 min 55 sec
Resyncs:                	9 (since 18 Nov 2018 22:37:15)
			
				Downstream	Upstream
Line attenuation (dB):  	29.5		0.0
Signal attenuation (dB):	Not available on VDSL2		
Connection speed (kbps):	20864		1565
SNR margin (dB):        	5.1		6.2
Power (dBm):            	8.9		4.8
Interleave depth:       	4		1
INP:                    	54.00		0
G.INP:                  	Enabled		Not enabled
Vectoring status:       	5 (VECT_UNCONFIGURED)		

RSCorr/RS (%):          	1.2582		0.0000
RSUnCorr/RS (%):        	0.0000		0.0000
ES/hour:                	0		0.72

 

And then to:

Stats recorded 01 Dec 2018 19:10:30

DSLAM type / SW version:	BDCM:0xb12d (177.45) / v0xb12d
Modem/router firmware:  	AnnexA version - A2pv6C038m.d24j
DSL mode:               	VDSL2 Profile 17a
Status:                 	Showtime
Uptime:                 	3 days 15 hours 28 min 14 sec
Resyncs:                	10 (since 18 Nov 2018 22:37:15)
			
				Downstream	Upstream
Line attenuation (dB):  	29.5		0.0
Signal attenuation (dB):	Not available on VDSL2		
Connection speed (kbps):	25129		1525
SNR margin (dB):        	2.9		6.3
Power (dBm):            	10.3		4.6
Interleave depth:       	4		1
INP:                    	54.00		0
G.INP:                  	Enabled		Not enabled
Vectoring status:       	5 (VECT_UNCONFIGURED)		

RSCorr/RS (%):          	468.9750		0.0000
RSUnCorr/RS (%):        	0.0000		0.0000
ES/hour:                	0.21		1.72

.. really low downstream SNR - giving me great downstream (yay!)... but poor upstream.

 

 

So - finally - to my question. Is there anything you can do (please!) to get my line to sync with less-aggressive downstream speeds in order to get me better upstream speeds? Clearly it's possible because my line was doing it two weeks ago.

 

Thanks,


Bobsta

 

23 REPLIES 23
dvorak
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?


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OskarPapa
Plusnet Alumni (retired)
Plusnet Alumni (retired)
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Registered: ‎09-10-2018

Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Hi @Bobsta, thanks for your post.

 

Unfortunately we aren't able to make any sort of meaningful change to the SNR on fibre connections, particularly when the line profile etc on the line is correct.

 

At the moment we're showing that your upstream is syncing at around 1.5mbps. Does this reflect with what you're seeing? -Owen

Bobsta
Grafter
Posts: 61
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Registered: ‎23-12-2011

Re: Protecting my upstream speed - turning off aggressive downstream SNR...?


@OskarPapa wrote:

Unfortunately we aren't able to make any sort of meaningful change to the SNR on fibre connections, particularly when the line profile etc on the line is correct.

 

OK, thanks. That's unfortunate - but worth asking.

 

At the moment we're showing that your upstream is syncing at around 1.5mbps. Does this reflect with what you're seeing? -Owen


Yup, and it seems pretty stable there. Let's hope it doesn't drop any lower.

Gandalf
Community Gaffer
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

No worries.

Fingers crossed your speeds go in the upwards direction.

Let us know if you need any further assistance.

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Plusnet
dws1900
Aspiring Pro
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Registered: ‎17-09-2018

Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Hi

Curious as to the length of your line, a GEA test will show the estimated length.

For what it is worth, mine is 1.5- 1.6 km, us 2.3 Mbs ds 20.4 Mbs. 

The line is all underground.

The line is not impacted as far as I can tell.

I have a DrayTek 2860, with Qos and Hardware (de)acceleration off.

 

SNR sits at about 4db typically.

Here are some stats

Actual Rate 22071 Kbps 2458 Kbps
Attainable Rate 22091 Kbps 2415 Kbps
Path Mode Fast Fast
Interleave Depth 1 1
Actual PSD 7. 1 dB 12. 4 dB
Bobsta
Grafter
Posts: 61
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Registered: ‎23-12-2011

Re: Protecting my upstream speed - turning off aggressive downstream SNR...?


@dws1900 wrote:

Hi

Curious as to the length of your line, a GEA test will show the estimated length.

For what it is worth, mine is 1.5- 1.6 km, us 2.3 Mbs ds 20.4 Mbs. 

The line is all underground.

 

Good point. I’d like to know the line length but I don’t think I can run a GEA test. Plusnet admins, is that something you can sort for me please?

 

 

The disappointing thing is that I had this line newly installed about 2 years ago. I deliberately kept my old line active and ordered a new line, meaning a lovely Openreach engineer came round and ran some new copper from my house, across a couple of poles and then underground. I suspect the underground run - which is most of the length - is old, wet and generally pretty nasty. But it’d be good to have an official estimate on the line length.

 

 

I’m connected to a Huawei cab so am using a Huawei HG612 modem to try to get the best sync. But am open to suggestions if folks feel there’s better kit out there these days.

adamwalker
Plusnet Help Team
Plusnet Help Team
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Hi Bobsta, here's the info you've asked for I've included a full GEA and I've highlighted line length for you:

 

If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
dws1900
Aspiring Pro
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Hi

For comparison see attached.

Note on yours there appears to be some interference detected, and your retransmission is high compared to mine.

I have crosstalk, you appear to be clear.

You are 28m closer to the dslam than me.

My house has an extension to the office where the modem is, using the BT approved cable and faceplate.

As stated in my previous post my line is all underground.

Hope this helps

 

 

 

 

Bobsta
Grafter
Posts: 61
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Registered: ‎23-12-2011

Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Thanks Adam and dws1900. That makes interesting reading.

 

My line has about 100m above ground and the rest below. The above ground bit is 2yrs old and comes straight into my master socket, then filter and modem. No extensions, no potential for interference in the property.

 

I know the below ground bit is old and probably quite suspect. My neighbours have had numerous Openreach visits this past 12 months and have been switched to a new pair ... I think it's just the luck of the draw with long copper runs. If only they'd build us a cabinet or pole-mounted DSLAM out here. Or do FTTPoD at a more reasonable price point.

ejs
Aspiring Hero
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

I think the only property with no potential for interference would have no electricity, so you wouldn't even be able to power the modem.

dws1900
Aspiring Pro
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Interference can come from many sources, radio transmissions, vehicles, atmospherics and electrical equipment to name a few.

It can be spatial or conductive.

Telephone lines on posts make good antenna's

ADSL/VDSL use radio signals in the LF/MF/HF bands.

This is the reason the signal drops off the longer lines, this is called attenuation.

The Kitz site has a wealth of information, see REIN for example.

A battery powered modem would still potentially suffer from external interference, crosstalk and contention.

dws1900
Aspiring Pro
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

@Bobsta

Your modem seem to be a bit slack on providing some information, what make is it.

Some of the line attenuation figures are missing, for completeness these are mine

 

Attenuation 31 dB downstream 37 dB upstream

 

 

Bobsta
Grafter
Posts: 61
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Registered: ‎23-12-2011

Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Thanks chaps. Yep, I’m very aware of how electrical signals, interference and attenuation work - I have a degree in electronic engineering from the ‘90s and can still remember a few bits of it. Wink

My comment about no sources of interference in the house was intended to avoid the usual suggestions you get when discussing this stuff (disconnecting extensions, using master socket, unplugging fax machine, etc.)

I actually had severe issues with suspected interference on a (now unused) line when I first moved into the house 7 years ago. Spent months trying to understand why my ADSL connection would suddenly re-sync to half its speed and then jump back again hours later. Looked at whether it was weather related, tried to ascertain if it could be caused by radio transmissions from a nearby small airport, or potentially from the nearby industrial unit that may have high load induction motors, arc welding equipment, etc.

In the end it turned out the copper pair had been damaged by years of rubbing against moving trees and had microscopic breaks in it, which also created crackling on the phone line. Once I spotted that Openreach were happy to replace the copper (although it did take them 9 months of faffing around with planning road closures to get a cherry picker in, etc.)

Anyway, I digress. What I’m slightly mystified about is why this (new) line would sync quite happily at over 2Mbps upstream 12 months ago but now won’t go above 1.5Mbps.
My previous assumption was increased crosstalk but it looks like that’s not correct, and the regular daily/constant interference pointed out in the GEA report seems more likely. The question now is can I get Openreach out to look into this, or are they just going to say “it’s working within tolerances” and refuse to help?
dws1900
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Re: Protecting my upstream speed - turning off aggressive downstream SNR...?

Interference is a pain to detect, but hopefully not stating the obvious, power down every thing, do a test, using the master socket

Also strongly recommend the Kitz site and the REIN topic (having suffered interference whilst on ADSL prior to Plusnet, I actually spoke to an OR REIN guy, interesting, it turned out to be a dodgy psu in a house down the road)

The symptoms for me were a drop of 2mbs on the downstream , and the snr up by 3db.