VDSL Performance & Tuning

Forums › New Zealand Broadband › VDSL Performance & Tuning

1 | ... | 274 | 275 | 276 | 277 | 278 | 279 | 280 | 281 | 282 | 283 | 284 | ... | 285

'That VDSL Cat'
13036 posts

Uber Geek
+1 received by user: 3896

ID Verified

Trusted

Lizard Networks

Subscriber

#1916988 11-Dec-2017 20:37

freakngeek:

I don't think ddDLM is lowering your connection rate, its some sort of noise lowering your actual and attainable speeds while synced.
ddDLM would reset the connection and either raise your SNR profile or raise the Interleave depth (not visible on a Fritzbox)
Either would mean even after a resync your connection rate would remain lower.

ddDLM can also adjust PSD and such.

if you look at the line itself, Noise isn't changing but bitloading is.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

miked

207 posts

Master Geek
+1 received by user: 22

Trusted

#1917008 11-Dec-2017 21:46

But it must be a pretty transient problem then, if a re-sync puts it immediately back to 53/19. Presumably whatever caused the dropout and slower speed has gone by then... so I'm being held falsely on a slow speed just by that being the current sync speed, but the line is back to being capable of 53/19 again.

Certainly it stays at the slow 15/10 speed for as long as I am patient enough to leave it seemingly without it fixing itself. Until Mike re-synced it for me today, I had patiently left it on 15/10 for a whole week.

Up until now, I have steadfastly avoided manual re-syncs hoping Chorus or ddDLM would finally find a balance point and stay there... but not yet!

One thing I've just asked for is whether they will do a pair swap. One of the last things they did on my line (as part of the troubleshooting before they started fixing things) before finally agreeing to replace the overhead span (that fixed the rain dropouts)... was a pair swap. As it turns out, that was an unnecessary job and it actually slowed my sync speed from 25/6 to 19/5 (via and even slower 16/2!!). So I think it is pretty safe to say I got put onto a noisier pair in the underground bundle. I did ask them to swap me back before the next stage of the work kicked in, but that never happened. Since then, I've had the new overhead span installed, and the multiples/taps removed for this whole section of the street... but my remaining problems could be as simple as being shifted onto a problematic pair in that last phase of troubleshooting.

The frustrating part was the pair swap was completely unnecessary from a technical perspective, as the only place that rain could cause immediate disconnections was the overhead span (everything else having been swapped or replaced several times in the two years of problems on this line! Including a previous underground bundle pair swap!), but they had to rule it out as part of the troubleshooting. So although it was annoying and unhelpful, it was a necessary step to getting the rain-disconnects fixed... so that is at least one good outcome!

I guess if you think it is noise related, I could try moving just top option back to the right again (which as I understand it reverses the 1db noise margin change), but instead just leave (or increase) the other two. That might help stability but at a higher sync speed than 39/19.

hio77

'That VDSL Cat'
13036 posts

Uber Geek
+1 received by user: 3896

ID Verified

Trusted

Lizard Networks

Subscriber

#1917011 11-Dec-2017 21:50

pair swaps are easy, replacing a leadin requires work..

Different tech requirements etc..

one thing that the Vectoring changes will bring in, is issues like this will ideally be nullvoid. as the speed will drop while the errors spike then raise back up (SRA)

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

Chorusnz

436 posts

Ultimate Geek
+1 received by user: 603

Trusted

Chorus

#1917479 12-Dec-2017 15:05

Hi all, quick breakdown of the work we have undertaken.

We've looked at the street as a whole, as opposed to one connection. We then started a project to bring better broadband to the entire street. The overhead span was replaced (which was the source of the water ingress fault) and we then moved on to getting multiples removed. This required some digging as well as regrouping cable pairs to optimise service and reduces cross-talk.

After we did all this, we saw a marked improvement in performance of connections on the street.

We're going set impulse noise protection on miked's line to INP=2, 8 milliseconds latency and changing the noise margin from 6 to 8 (for both up and down), to tackle the current error rate.

coffeebaron

6306 posts

Uber Geek
+1 received by user: 3569

Trusted

Lifetime subscriber

#1917499 12-Dec-2017 15:46

Chorusnz:

we then moved on to getting multiples removed. This required some digging as well as regrouping cable pairs to optimise service and reduces cross-talk.

Do you want some more streets to remove multiples from?? I can advise a couple in competing UFF areas :)

Rural IT and Broadband support.

Broadband troubleshooting and master filter installs.
Starlink installer - one month free: https://www.starlink.com/?referral=RC-32845-88860-71
Wi-Fi and networking
Cel-Fi supply and installer - boost your mobile phone coverage legally

Need help in Auckland, Waikato or BoP? Click my email button, or email me direct: [my user name] at geekzonemail dot com

miked

207 posts

Master Geek
+1 received by user: 22

Trusted

#1917519 12-Dec-2017 16:19

Talking to Mike ( @ChorusNZ ) on the phone today, it turns out others in the street are also having a similar problem as mine, so I'm being used as the guinea-pig to see if the problems get resolved by these changes... and if so, these changes will be made manually to the other connections displaying problems. I'm personally hoping that if the problems go away, that we might be able to further tune the connection to drop the margin back down to 7db (and possibly even just the up direction - returning the down to 6db if it all works OK like that).

To make this all possible, I've backed out my changes in the Fritz!Box, so they are back to the default maximum speed settings. (so the modem and DLM aren't competing)

For those interested, I am currently showing 46/12Mbs on these new settings from today's tuning work with the following stats:

and Spectrum:

Mike also thinks a line swap wouldn't be necessary now, because as part of the multiple removal, they disconnected all the lines, and checked them, graded them, then re-allocated them logically after all the work, so it is unlikely to be the cause of these problems.

Thanks everyone for the input.

Miked

Dell

Shop now for Dell laptops and other devices (affiliate link).

miked

207 posts

Master Geek
+1 received by user: 22

Trusted

#1917561 12-Dec-2017 16:25

@hio77 We discussed RFI as a possible cause this morning, which would normally be Mike's hunch too in these situations, but apparently there is no evidence of RFI in this case, which makes it trickier to track down. (something like that anyway...)

Mike

Chorusnz

436 posts

Ultimate Geek
+1 received by user: 603

Trusted

Chorus

#1917565 12-Dec-2017 16:33

coffeebaron:

Do you want some more streets to remove multiples from?? I can advise a couple in competing UFF areas :)

There's always things in the pipeline to improve services, We'll release further info on upgrades as it becomes available so keep an eye on our site

hio77

'That VDSL Cat'
13036 posts

Uber Geek
+1 received by user: 3896

ID Verified

Trusted

Lizard Networks

Subscriber

#1917629 12-Dec-2017 18:22

miked:

@hio77 We discussed RFI as a possible cause this morning, which would normally be Mike's hunch too in these situations, but apparently there is no evidence of RFI in this case, which makes it trickier to track down. (something like that anyway...)

Mike

Looks like Mike has been all through it, as i suspected.

I'm personally tenative about software based fixes - generally the hardware obviously can't be up to scratch and is being covered for in that case.

However; i do have a particular situation that reacts slightly differently, low SNR on certain chipsets causing FD.

Can't really comment on specifics given that's chorus's end but at a broad angle, Seems to be low snr on some lines/modems really do struggle while the physical line is 'up to spec'

Ideally these sorts of bursts are where G.INP would help - @ChorusMike how about trailing that too ;)

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

miked

207 posts

Master Geek
+1 received by user: 22

Trusted

#1923424 21-Dec-2017 21:33

Quick status update for those interested. Last week, Mike had manually tweaked the settings which gave me 46/12Mbs. Then the next day it rose 51/14Mbs (I suspect Mike reduced the margin from 8db to 7db for that).

Not noticed what speed I've been at for the last week, but this morning the street had a powercut and reconnected afterwards at 68/25Mbs (which unfortunately lost all the router logs).

Errors are visible on the line, but it has held on at that speed all day, albeit with a very low noise margin.

Shows the potential of the line now though (speedtest.net via Wifi showed speeds of 66Mbs/24Mbs, so it is the real deal)... crazy to think just a few months back I was stuck at 12Mbs/4Mbs on this line!!

Don't think it will hold on to this speed forever though, so fully expecting to return to a slower speed in due course as the errors climb.

Stats at 68Mbs/25Mbs:

Spectrum at 68Mbs/25Mbs:

hio77

'That VDSL Cat'
13036 posts

Uber Geek
+1 received by user: 3896

ID Verified

Trusted

Lizard Networks

Subscriber

#1923608 22-Dec-2017 11:07

Looks to me like adjustments are being made to PSD levels.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

Lenovo

Shop now for Lenovo laptops and other devices (affiliate link).

olivernz

512 posts

Ultimate Geek
+1 received by user: 177

ID Verified

Trusted

Lifetime subscriber

#1935369 10-Jan-2018 10:15

Hey,

Thought I'd ask here instead of opening a new thread.

My VDSL connection (usually 4up/20down) has suddenly dropped to 0.5up/20down. This was at 4am about 3d ago. Since then Chorus must have had a look at the line remotely and changed something as it's now about 0.85up. When this drop happened there was bad weather with rain and wind (but we've had far worse). From what I see on my Fritzbox nothing has really changed. I have made no changes.

I have done the 15min reset DSLAM thing several times and actually removed my line filter (not that there is anything bar VDSL on the line). Rebooted FritzBox several times. Visually checked the line to the mast. Nothing obvious anywhere. I suspect some effect by weather i.e. branches or water ingress.

BUT. What would drop upload speeds but not affect download rate???? I find that extremely weird. I also don't think the FritzBox is bust but heck I have no other VDSL modem so can't prove that.

Maybe someone has a tip. Chorus should be round in the next days to check but haven't got a time yet.

Cheers Oliver

olivernz

512 posts

Ultimate Geek
+1 received by user: 177

ID Verified

Trusted

Lifetime subscriber

#1936049 11-Jan-2018 10:07

Update: 3d later everything is back to normal. DSLAM reset connection at 4:03AM today and voila I'm back at 2.5MBit. Not quite where I was but enough. So was all a DSLAM issue?!?

hio77

'That VDSL Cat'
13036 posts

Uber Geek
+1 received by user: 3896

ID Verified

Trusted

Lizard Networks

Subscriber

#1936232 11-Jan-2018 13:43

olivernz:

Update: 3d later everything is back to normal. DSLAM reset connection at 4:03AM today and voila I'm back at 2.5MBit. Not quite where I was but enough. So was all a DSLAM issue?!?

I've seen this happen before where bands simply turn off or software defined bridgetaps essentially show up..

Never been able to explain it...

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

CitizenErased

208 posts

Master Geek
+1 received by user: 50

#1942136 18-Jan-2018 19:42

Is the following situation unusual for VDSL: Downstream line rate 41,765 kbps and upstream line rate 1,244 kbps?

This connection was upgraded from ADSL, which had a line rate of about 20 Mbps down and 1.1 Mbps up. There was already a central splitter in place, but I plan to get the internal wiring checked and run a new line if necessary.

Here's a screenshot from the router status page with some more info:

I tested the connection with another brand of router, in case that was a factor. The results were almost identical.

1 | ... | 274 | 275 | 276 | 277 | 278 | 279 | 280 | 281 | 282 | 283 | 284 | ... | 285