VDSL Download Sync Rates Dropped From 37.5Mbps to 27.1Mbps (28%)

Forums › New Zealand Broadband › VDSL Download Sync Rates Dropped From 37.5Mbps to 27.1Mbps (28%)

gravitini

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#145317 14-May-2014 18:58

Hi everyone,

I'm hoping someone can help me understand this better.

Switched over to Voyager Naked VDSL 1TB plan for my home office on 15th April 2013 and it's been pretty great on all levels for both work and personal.

Recently my download sync rates have dropped significantly.

I only have two historical stats samples and in hindsight I should have kept regular stats samples.

On the 16th June 2013 my sync rates were:

Profile UP Speed Down Speed SNR Upstream SNR Downstream
8b 10336 (Kbps) 37529 (Kbps) 167 (0.1dB) 124 (0.1dB)

Until recently my download sync rates have always been around 35-37 Mbps and I have been able to fully utilise that with Voyager.

On the 2nd May 2014 my sync rates were:

Profile UP Speed Down Speed SNR Upstream SNR Downstream
8b 10330 (Kbps) 32031 (Kbps) 145 (0.1dB) 57 (0.1dB)

On the 5th May 2014 my sync rates were:

Profile UP Speed Down Speed SNR Upstream SNR Downstream
8b 10349 (Kbps) 27271 (Kbps) 152 (0.1dB) 115 (0.1dB)

Nothing has changed on my side.

How do you suddenly lose 8-10 Mbps on your download sync rate?

My setup is:

dedicated line with single jack < 1m from demarc
router to post is 40m and post is 380m walk distance to cabinet = 420m
Draytek Vigor 2750
no other devices
no other jacks
no changes or recent road works

After seeing the drop to 27Mbpps I requested a VDSL line check with Voyager on 5th May 2014.

Chorus tech visited on 8th May 2014 around 10:30am:

no issues with internal wiring, jack or post to demarc (identical results with Chorus test modem at jack and post)
rough distance calculation was just under 500m
expectation would be close to 40Mbps
will try a port swap then escalate to cable

Port swap was a complete fail and was disconnected with the modem attempting to train on a 30a profile.

Voyager escalated and was reconnected at 6pm on 9th May 2014.

After the port swap my current sync rates initially dropped to 25.4Mbps then stabilised around:

Profile UP Speed Down Speed SNR Upstream SNR Downstream
8b 10349 (Kbps) 27126 (Kbps) 154 (0.1dB) 115 (0.1dB)

Response from Chorus was:

"Hi team, cable trace shows the distance is approximately 567 meters from the cabinet, with a bridge multiple of approximately 39.4 meters. prequal shows the download rate range for VDSL is between 18.8 and 26.9 mbps, current sync rate is 27128/10352kbps, connection rate is within specifications."

That statement conveniently matches my current sync rates.

My download sync rates have been 35-37 Mbps until very recently. How does this match up with what Chorus is saying???

That distance estimate is significantly higher than expected.

How do they estimate the distance? Is that reliable with a degraded line?

Chorus closed the fault and I've asked Voyager to reopen again:

requesting a pair swap
highlighting my historical stats over 27Mbps
requesting clarification on the cable trace distance (actual vs estimate)
requesting an explanation of why the recent drop in download sync rates

There is no fibre planned for this area so VDSL is my only option and I want my full service restored.

Thanks,
Mike

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#1045051 14-May-2014 18:58

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.

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johnr

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#1045059 14-May-2014 19:01

As more users connect to VDSL rates will drop due to cross talk and another ISP connecting users to VDSL with no master filter (Not Vodafone)

RunningMan

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#1045060 14-May-2014 19:02

As more customers in the same feeder get VDSL then crosstalk from adjacent pairs increases, background noise goes up, and the speed goes down to maintain stability.

There's plenty of threads around from early adopters of VDSL who have seen the same thing as it becomes a mainstream product - it's just the way the technology works.

EDIT: Beaten to it by johnr!

Coil

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#1045062 14-May-2014 19:05

I can merely say good luck.

Chorus will probably trump all efforts and say "VDSL is a best effort service, To specification"
Your line might have had high errors or alike and DLM has done its work. My line once connected at 49Mbp/s, Now im lucky to get 42/43... Many factors, I have 375m cable run and 2 neighbors with VDSL.
Your line at 500m you would expect around 25-35Mbp/s. Given cable quality, join quality and crosstalk.

Please what ever you do dont get hopeful as you will be let down..

Cheers

Edit..

Beaten by the above buggers :)

Inphinity

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#1045068 14-May-2014 19:20

As far as I'm aware there's no guarantees as to VDSL speed, other than if it's no better than ADSL2 on the same line you can roll back... so, good luck but, I don't see anything being done. Chances are, as above, it's just crosstalk and such.

Jase2985

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#1045071 14-May-2014 19:28

i lost 9mbps when my modem reconnected the other day when my UPS failed.

not much you can do about it if there are no wiring issues. just have to suck it up and unfortunately live with it

its a best effort service

as pointed out by someone else these types of threads are popping up 1-2 times per week by people who think that their speed when they joined is the speed they will/should always have.

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LittleDude

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#1045075 14-May-2014 19:32

I also experienced a similar drop recently. I was able to download at 8MB/s...now only 5MB/s(speedtests showed a similar decrease). Sadly you're not alone.

LittleDude

charsleysa

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#1045087 14-May-2014 19:56

Add me to the depressed list, mine went from 40 down to 30.

Regards
Stefan Andres Charsley

gravitini

11 posts

Geek

#1045098 14-May-2014 20:14

Hi everyone, thanks for the replies.

Small drops over time I was expecting not sudden big drops and I understand the impact of crosstalk.

The first step was to eliminate all the fault options:

modem (no issue)
internal wiring (no issue)
post to demarc (no issue)
port swap (no change)
pair swap (tbd)
DLM (tbd)

The one area I would like to understand is the Chorus cable trace and how they calculate distance, bridge multiple, etc.

I would pay for fibre if it was available... sadly it's not planned and the current planned rollout in June 2016 passes by on 3 sides (closest point is 150m).

What makes it even sadder is that I already have old unlit fibre at the post from a cancelled trial.

sbiddle

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#1045106 14-May-2014 20:26

I'd take a stab and say you're probably about the 20th person to start a thread on here in the last month or so raising such an issue..

Good luck to the Australians who haven't yet started building their FTTN network to replace the canned fibre and think that VDSL is a replacement for fibre!

Peppery

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#1045110 14-May-2014 20:28

I would say there's probably not a whole lot you can do - just the way the technology works. 27/10 is still very decent.

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hio77

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#1045658 15-May-2014 16:45

sounds like crosstalk has caused DLM profiles to jump around, and your sync rates have dropped from that.

unfortunately, vdsl is a copper product, and degradation overtime as more jump on board and such.

#include <std_disclaimer>

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

gravitini

11 posts

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#1351258 24-Jul-2015 17:22

After a year of download rates almost dropping below 20Mbps this has finally been resolved :-)

Profile

State

UP Speed

Down Speed

SNR Upstream

SNR Downstream

Showtime

8688 (Kbps)

50348 (Kbps)

80 (0.1dB)

63 (0.1dB)

The major cause seems to have been a nearby faulty external power service box with a 60A fuse that eventually melted into a black blob and was replaced by Vector.

hio77

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#1351259 24-Jul-2015 17:24

based off that snr, things look at bit funny still. looks likely the switch to 998 has hit you too.

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Jase2985

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#1351261 24-Jul-2015 17:31

gravitini:The major cause seems to have been a nearby faulty external power service box with a 60A fuse that eventually melted into a black blob and was replaced by Vector.

im going to say that wasnt whats caused your speed to go up, it was the switch to the new chours 998 band plan.

do you happen to live out howick ways?

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