Sudden decrease in VDSL download speed

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Zippity

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Topic # 165713 18-Feb-2015 10:50

One of VF's Moderators has suggested that I post on this Forum, as someone here may be able to help me

A couple of weeks ago I posted the following on VF's Community Services Forum:

"Since July 2014, I have been averaging a download speed of around 60.35 Mb/s and an upload of 9.69 Mb/s.

Last Friday, before heading away for a long weekend, I switched both my PC and Router off at the wall.

Upon returning late Sunday, I switched them both on again.

Today after running several Speedtests, my download speed has decreased to 48.48 Mb/s whilst the upload speed has remained static.

Will I be able to return to the higher download speed, am I losing out on the lower speed?"

Unfortunately, the "slower" download speed continues

Any comments/suggestions would be appreciated.

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Reply # 1241394 18-Feb-2015 10:50

Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

If you are posting regarding DSL speeds please check that

- you have reset your modem and router

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

- you are not being throttled by your ISP due to going over the monthly cap

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

- you read this topic and follow the instructions there.

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

- Your ISP and plan

- Type of connection (ADSL, ADSL2, VDSL)

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

- Your general location (or street)

- If you are rural or urban

- If you know your connection is to an exchange, cabinet or conklin

- If your connection is to a ULL or wholesale service

- If you have done an isolation test as per the link above

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

I recommend you read these two blog posts:

- Is your premises phone wiring impacting your broadband performance? (very technical)

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?

I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.

sbiddle

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Reply # 1241435 18-Feb-2015 11:00

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The simple answer to your question is that nothing is wrong. There is also nothing that can be done to get that higher speed back, because there is nothing wrong.

Sync speeds are determined by many thing including line attenuation, the quality of the line, and external factors such as noise from other connections within the same MPF.

Every time you power cycle your modem it has to resync with the ISAM. DLM software on the ISAM monitors a connection and determines connection settings that will deliver the best connection quality. Best quality does NOT mean best speed.

Right now DLM and the ISAM have determined that this is the best profile and speed for your connection, and nothing will change that. Over time there is a slim chance speeds could go back up, but that's certainly not guaranteed. Resetting the DLM profile may be suggested by others but that probably do anything significant because as I said in my first sentence there is nothing wrong. DLM has determined this is the best profile for your connection at this time.

Over the past year VDSL2 sync speeds have gradually dropped for many people, in part due to far end crosstalk impacting connections within the same MPF. This is the real world reality of xDSL and it's performing exactly as designed.

Your best hope of a speed increase again is the Chorus 997/998 bandplan change later in the year.

DarkShadow

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Reply # 1241437 18-Feb-2015 11:01

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First world problems lol, I can't even get 30Mbps on my VDSL.

4possm

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Reply # 1241442 18-Feb-2015 11:05

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DarkShadow: First world problems lol, I can't even get 30Mbps on my VDSL.

I'm sitting at 13Mbps on VDSL.... FML First world problems for sure.

xpd

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Reply # 1241444 18-Feb-2015 11:06

Had similar twice at home late last year - first time was a branch rubbing on the line exposing the core to the world. Second time was the line was looped around the telephone pole a few times and had frayed against that. Chorus fixed both issues (and we removed the tree causing the first time) and its bene fine since.

So check for any damaged cabling that could be exposed to the elements.

XPD / Gavin / DemiseNZ

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https://www.xpd.co.nz - Games, geeks, and more.

Sideface

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Reply # 1241459 18-Feb-2015 11:18

DarkShadow: First world problems lol, I can't even get 30Mbps on my VDSL.

VDSL envy

I got 14/4 Mbps when I tried VDSL - despite perfect house wiring and a master filter.
Went back to ADSL2.

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Jase2985

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Reply # 1241460 18-Feb-2015 11:19

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you would have have a very stable connection at 60mbps, when you dicsonnected (powered off the router) its reconnected, and when its reconnected its decided that the noise/other factors on the line is a little higher and its dragged back the download speed to compensate.

I had a similar thing, want from 63/10 to 50/10 and im back at 55/10.

all you can do is wait and see if you get the speed back, but there is nothing anyone can really do to get you speed back.

lesson learned, dont turn off your modem if you are on VDSL

dolsen

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Reply # 1241485 18-Feb-2015 11:56

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Get a UPS. Wait for a power outage in your area. Reboot the modem at that time and hope for the best :-)

Zippity

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Reply # 1241487 18-Feb-2015 11:58

What could I expect if I turn the Router off at the wall again and leave it off for a couple of hours?

A worse or better download rate?

hio77

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Reply # 1241495 18-Feb-2015 12:07

Zippity: What could I expect if I turn the Router off at the wall again and leave it off for a couple of hours?

A worse or better download rate?

Likely no change.

Normally a few disconnections in a day is enough to blow DLM-1 but it sounds like you have actually lost your 17a bandplan - ild check if this is actually the case.

Although it seems unlikely, maybe interference simply increased while you were away?

#include <std_disclaimer>

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

johnr

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Reply # 1241524 18-Feb-2015 12:21

As above this is not a fault and as more users connect up to VDSL the speeds will decrease further

sbiddle

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Reply # 1241531 18-Feb-2015 12:30

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Zippity: What could I expect if I turn the Router off at the wall again and leave it off for a couple of hours?

You could expect to be without internet for a couple of hours and will very likely have the exact same speed when you turn it back on.

Without trying to offend you I'm not sure how much clearer people need to be before you'll simply accept that what you're experiencing isn't a fault, that VDSL2 and DLM are working exactly as designed, and there is nothing you can do to influence the speed.

Zippity

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Reply # 1241566 18-Feb-2015 12:53

Sbiddle,

I accept that what happened has happened.

The excuse that it is not a fault, is BS.

If the simple act of my turning off the power for 2 days caused the change, then of course there is a fault, but I guess the suppliers would rather that I believe otherwise.

Thank you for your comments.

I will go back to being an idiot!

hio77

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Reply # 1241577 18-Feb-2015 13:00

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as i said, look into if your bandplan has changed.

If it has (which at first sight, i would say it likely has) This is a unpleasant thing to deal with, but there is physically no way an ISP can ask it to be put back persay, DLM handles it all and chorus don't allow isps to disable and go around that.

So unfortunately, you might never get that speed back, or it might just be a wait it out and see what happens game.

sure, its a fault from the point of view as it was working like this and then suddenly changed... but from an is it working as expected/designed point of view, there is no fault at all unfortunately.

#include <std_disclaimer>

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

Zippity

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Reply # 1241584 18-Feb-2015 13:05

Thanks hio77

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