Sudden decrease in VDSL download speed

Forums › One New Zealand (including Vodafone, WxC, Farmside) › Sudden decrease in VDSL download speed

1 | 2

sidefx

3711 posts

Uber Geek

Trusted

#1241589 18-Feb-2015 13:10

The other day I came to a traffic jam on the motorway and my car went from going at close to 100km/h down to 60km/h. I think my car has developed a fault! I'll be contacting the manufacturer forthwith.

/Tongue-firmly-in-cheek ;-)

"I was born not knowing and have had only a little time to change that here and there." | Octopus Energy | Sharesies
- Richard Feynman

Zippity

683 posts

Ultimate Geek

#1241671 18-Feb-2015 14:23

sidefx: The other day I came to a traffic jam on the motorway and my car went from going at close to 100km/h down to 60km/h. I think my car has developed a fault! I'll be contacting the manufacturer forthwith.

/Tongue-firmly-in-cheek ;-)

Ha Ha

Please keep this discussion apples to apples

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#1241681 18-Feb-2015 14:42

it pretty much is though. the slow down is due to something that is out of you or anyone else's control.

there is nothing you nor your ISP can do to change your speed. like people before in the thread have said its DLM doing what it was designed to do. Adjust your line speed to give the best compromise between errors, speed and latency.

it has done just that, you turned your modem off, its reconnected and its decided you should be connecting slightly slower to reduce the errors on your line. if you had have left it you would have more than likely stayed on 60+mbps till either the power went off or the errors got so high it had to reconnect and you would end up slower anyways.

no fault, nothing anyone can do. there is also no promised speed for VDSL, its between 15mbps and 70mbps, yours is in that range so it is what it is

stop worrying and move on to worrying about something else

sbiddle

30853 posts

Uber Geek

Retired Mod

Trusted

Biddle Corp

Lifetime subscriber

#1241700 18-Feb-2015 15:06

Zippity:

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.

There is no fault. A fault is when something doesn't work as designed. VDSL2 and DLM are working exactly as designed to give you the best possible connection.

If you'd turned your modem off for 30 seconds the same thing would have happened. Your line was probably seeing an increasing number of CRC errors, quite possibly from FEXT. After a resync occurred the ISAM selected what it believes is the best profile for your connection.

There are probably 20+ threads on here in recent months from people with the exact same issue. People need to accept that speed is NOT a measure of a quality connection, QoE is. DLM is designed to deliver an improved QoE. and if you disagree with that you should probably contact Alcatel Lucent and make your thoughts known to them.

Zippity

683 posts

Ultimate Geek

#1241774 18-Feb-2015 15:58

As I asked in my OP: "am I losing out on the lower speed?"

If the answer is NO, then I am happy.

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#1241778 18-Feb-2015 16:03

Zippity: As I asked in my OP: "am I losing out on the lower speed?"

If the answer is NO, then I am happy.

thats a slightly arguable topic.

at peak usage for you, yes you probably are missing out.

If you take average usage, ild bet it makes ZERO difference.

#include <std_disclaimer>

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

dolsen

1476 posts

Uber Geek

Trusted

Lifetime subscriber

#1241790 18-Feb-2015 16:24

Basically, there are multiple people who have all told you the same thing. This is not a fault, it is the expected scenario.

Think of motorways with a changeable limit based on traffic flows. Due to more people on the road, the overhead signs had the speed limit reduced.
If you wait until the roads are clear, the limit will probably go back up (hence my earlier suggestion to get a UPS and reconnect while the road / lines are clear). How you how you arrange the power outage is left to your imagination :-)

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#1241795 18-Feb-2015 16:32

dolsen: (hence my earlier suggestion to get a UPS and reconnect while the road / lines are clear). How you how you arrange the power outage is left to your imagination :-)

have tried that didnt make any noticeable difference :)

you are loosing out if you care for comparing speed tests, otherwise no you are not loosing out

and anyways there is nothing you can do about it anyways so....

sbiddle

30853 posts

Uber Geek

Retired Mod

Trusted

Biddle Corp

Lifetime subscriber

#1241800 18-Feb-2015 16:40

dolsen: Basically, there are multiple people who have all told you the same thing. This is not a fault, it is the expected scenario.

Think of motorways with a changeable limit based on traffic flows. Due to more people on the road, the overhead signs had the speed limit reduced.
If you wait until the roads are clear, the limit will probably go back up (hence my earlier suggestion to get a UPS and reconnect while the road / lines are clear). How you how you arrange the power outage is left to your imagination :-)

The motorway analogy isn't such a good one.

A better analogy would be to compare it to a motorway that now has a permanent speed reduction because the road condition (QoE) has changed and you'll end with damage to your car if you continue at that speed. The damage in this case is CRC errors which impact the connection.

A reboot while nobody else is connected won't make any difference - the ISAM is responsible for setting the profile and speed to what it things will offer the best outcome.

richms

28168 posts

Uber Geek

Trusted

Lifetime subscriber

#1241823 18-Feb-2015 17:19

I get signifigantly higher VDSL and in the past ADSL speeds by causing a reboot during a power outage. Still on the same profile. See the noise margin go to 0 and it stop working within minuites of power coming back on however so its not as useful as it used to be where it would hang in there with 2-3dB of margin and keep working like that for months.

Richard rich.ms

Zippity

683 posts

Ultimate Geek

#1437023 28-Nov-2015 20:59

I'm back to decent speeds again

johnr

19282 posts

Uber Geek
Inactive user

#1437026 28-Nov-2015 21:09

Zippity: I'm back to decent speeds again

Band plan change from 997 to 998 on the serving exchange / cabinet

1 | 2