New VDSL2 - Strange speed issues. Request advice.

Forums › Spark New Zealand (including Skinny and BigPipe) › New VDSL2 - Strange speed issues. Request advice.

davidvg

16 posts

Geek

#146836 30-May-2014 14:30

I changed from ADSL (was getting 8 down) to VDSL2 on 5th May. The Chorus installer fitted a line splitter and said he measured the speed at 26 down and when I first checked the modem stats after he left it was at 28 down. Within a matter of 30 minutes this dropped to 15 down. After no improvement for a week I called Telecom and was told to give it another 2 weeks whereupon some magic would happen and things would improve. The Telecom minion had spoken with a forked tongue - it stayed at 15 max. I called and escalated the problem. Today I received a message that 18 was the max that the line would take and there had been some adjustment at their end . I rebooted the new Telecom modem and was thrilled to see that I was connected at 28 see below:

Alas within the half hour:

So, are Telecom/my Modem behaving like a bank and offering me a teaser rate, just to disappoint me later?

Why the sudden (30 mins) drop - if the modem can connect at 28 then why is it throttling back to 15?

I am in rural Northland 600m from a local cabinet. I changed to the new unlimited plan when the VDSL was installed.

Thanks.

PeterReader

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#1056556 30-May-2014 14:30

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.

nigelj

856 posts

Ultimate Geek

#1056576 30-May-2014 14:44

21db Down Attentuation seems a tad high for VDSL especially for 600m from a cabinet (is there more than one cabinet in your area, or prehaps a roundabout method of wiring that Chorus may have taken to your property?).

What were your pre-VDSL stats?

davidvg

16 posts

Geek

#1056636 30-May-2014 16:32

nigelj: 21db Down Attentuation seems a tad high for VDSL especially for 600m from a cabinet (is there more than one cabinet in your area, or prehaps a roundabout method of wiring that Chorus may have taken to your property?).

What were your pre-VDSL stats?

There's only one cabinet that I know of.
On the old ADSL I noted down these stats:

Data Rate 8160 640
SNR Margin 18 12
Line Attenuation 17 7

The line does have a subterranean journey under a couple of paddocks which probably adds another 150 m to the distance so
probably 750m from the cabinet in total.
Cheers

RunningMan

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#1056641 30-May-2014 16:42

With an ADSL downstream attenuation of 17dB, you are a lot higher than the rule of thumb limit of 10.8dB for VDSL. I'm surprised that VDSL was installed.

That attenuation correlates well with the 21dB attenuation you are seeing on VDSL, which looks about right for your sync rate.

Do a search for "DLM" - Dynamic Line Management. It basically fine tunes your line to get the most reliable connection, in your case at the sacrifice of speed. This will be causing the drop from 28 to 15.

Basically, be happy that you have a much better upload speed, and don't expect much more. I'd expect the physical cable run to be higher than 750m to the cabinet.

hio77

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#1056670 30-May-2014 17:40

it would appear like you shouldnt have really gotten VDSL at all due to your distance, although i have heard rural lines are a little more relaxed on this requirement.

prevdsl, looks like you might even have been connecting on adsl1 or your line was just horrid in the first place (which your line stats do point towards).

sounds like you got a really nice sync, but it was FAR too much for your line, and DLM pulled it back.

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RunningMan

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#1056702 30-May-2014 18:33

Any electric fences anywhere near the cable route?

They're never a good thing for xDSL...

michaelmurfy

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#1056707 30-May-2014 18:42

RunningMan: Any electric fences anywhere near the cable route?

They're never a good thing for xDSL...

My thought also, I've seen electric fences drop a 10mbit ADSL2+ connection to 2mbit...

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davidvg

16 posts

Geek

#1056778 30-May-2014 19:16

RunningMan: Any electric fences anywhere near the cable route?

They're never a good thing for xDSL...

yep - lots of electric fences and the cable travels under a couple of 'em. I can't get rid of them (much as the critters would like
me to) and I know it plays hell with line quality.
The sudden drop in speed is more likely to be DLM as RunningMan suggests so it would appear that I'm stuck with what I've got
which is an improvement on what I had!
Thanks to all who replied
Cheers.

nigelj

856 posts

Ultimate Geek

#1056869 30-May-2014 21:05

davidvg:
RunningMan: Any electric fences anywhere near the cable route?

They're never a good thing for xDSL...

yep - lots of electric fences and the cable travels under a couple of 'em. I can't get rid of them (much as the critters would like
me to) and I know it plays hell with line quality.
The sudden drop in speed is more likely to be DLM as RunningMan suggests so it would appear that I'm stuck with what I've got
which is an improvement on what I had!
Thanks to all who replied
Cheers.

Is your farmland/block in a way (large enough for instance) that you could isolate the fences near the phone cable for a few days? (I.e. move the stock to other paddocks and disconnect the fence to a couple of paddocks), if so, you could try and apply the 'isolation test' theorum to the running of your fence, ask your DLM to be reset to scratch (clean slate basically) and see if that impacts your line. At least then you'd be able to tell if there may be anything you can personally do to improve the quality.

RSM have a quick guide on fences and RFI that you may find interesting http://www.rsm.govt.nz/cms/pdf-library/customer-support/5-step-electric-fence-interference.pdf/view if you decide to put a couple of days leg work into fence improvement. True no-8 wire work!

quickymart

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#1056875 30-May-2014 21:12

Problem is (in a rural area, anyway) quite often the fence isn't yours and your neighbour doesn't want to know. I speak from experience on this one.

nigelj

856 posts

Ultimate Geek

#1056880 30-May-2014 21:21

quickymart: Problem is (in a rural area, anyway) quite often the fence isn't yours and your neighbour doesn't want to know. I speak from experience on this one.

Agreed, but from one of OP's earlier posts:

The line does have a subterranean journey under a couple of paddocks which probably adds another 150 m to the distance so probably 750m from the cabinet in total.

20% of the cable is under a fence that potentially he controls (wording sounds like it's just a cable up a long rural driveway), so if he has control over that energiser, then it's worth a shot to try and optimise it.

davidvg

16 posts

Geek

#1056884 30-May-2014 21:58

nigelj:
davidvg:
RunningMan: Any electric fences anywhere near the cable route?

They're never a good thing for xDSL...

yep - lots of electric fences and the cable travels under a couple of 'em. I can't get rid of them (much as the critters would like
me to) and I know it plays hell with line quality.
The sudden drop in speed is more likely to be DLM as RunningMan suggests so it would appear that I'm stuck with what I've got
which is an improvement on what I had!
Thanks to all who replied
Cheers.

Is your farmland/block in a way (large enough for instance) that you could isolate the fences near the phone cable for a few days? (I.e. move the stock to other paddocks and disconnect the fence to a couple of paddocks), if so, you could try and apply the 'isolation test' theorum to the running of your fence, ask your DLM to be reset to scratch (clean slate basically) and see if that impacts your line. At least then you'd be able to tell if there may be anything you can personally do to improve the quality.

RSM have a quick guide on fences and RFI that you may find interesting http://www.rsm.govt.nz/cms/pdf-library/customer-support/5-step-electric-fence-interference.pdf/view if you decide to put a couple of days leg work into fence improvement. True no-8 wire work!

Thanks for the link. I can, in fact, turn off the fence energizer to the affected area ( I do know the subterranean route of the cable) for a week or more soon and I'll do as you suggest - it's certainly worth a shot.
Many thanks.