How to influence VDSL latency (DLM) profile?

Forums › New Zealand Broadband › How to influence VDSL latency (DLM) profile?

ctucks

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#201363 15-Aug-2016 17:32

As above. Our VDSL connection has been a little strange with changing DLM profiles. It started on DLM-1 (1ms), giving us the lowest possible latency, much like being on an un-interleaved ADSL connection. However, a few weeks later, the modem reset and the latency increased by about 16ms, probably bumping us up to DLM-2. It has remained at DLM-2 for quite a while now. Although, the other day our profile did drop back down to DLM-1 for 4 days, then last night, the modem reset once again and it shifted back up to DLM-2. I'm not too sure why it won't just stay on DLM-1? It's been 100% stable while on DLM-1, and the decreased ping is something I really appreciate.

Our modem is generally very stable, no random resets except for these DLM profile swaps. Speed has been the same on all DLM profiles too, so shifting to a higher latency profile for speed benefits isn't the case at all. I'm not sure if there is anything the ISP can do, but as far as I can tell its out of my hands.

PeterReader

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#1612071 15-Aug-2016 17:32

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:

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darylblake

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#1612098 15-Aug-2016 17:52

No there is nothing you/they can really do.

You can have your port reset, but they will only do it if there are problems with your line. This will reset the profile, but it will be crappier after a reset and have to and learn DLM again.

The best thing you can possibly do is not to keep plugging/unplugging it. I about 100m from the cabinet, plugged into an ikanos card. With my 17a profile I get 65mbit down and 25 up. Its plenty and my ping is about 4ms to the B-RAS. It will go the best it can do with time provided you leave it and don't fiddle with it.

thecatsgoolies

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#1612103 15-Aug-2016 18:14

Don't request a port reset

ctucks

34 posts

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#1612110 15-Aug-2016 18:22

Should I just sit it out and see if it changes?

thecatsgoolies

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#1612114 15-Aug-2016 18:29

You can't do anything else anyway

hio77

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#1612115 15-Aug-2016 18:38

sit it out and wait.

To influence it you have two things you can do.

Avoid DSL resyncs
Ensure your connection is as clean as possible on your internal wiring (this is to avoid errors)

Pray for the best always helps..

Do not get a reset, depending on how this is done it can actually in the long run loose a fair chunk of your top speed. Why isn't exactly logical to figure out, but it does happen. Many of us have been burnt..

#include <std_disclaimer>

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

ctucks

34 posts

Geek

#1612116 15-Aug-2016 18:42

Yeah...

VDSL is so frustrating! It's bad enough that we're not that close to the exchange, I think there is a closer cabinet to us that we're not connected to. Our downstream line attenuation is like 25db! I hope fibre comes sooner rather than later, that's one thing I miss about living in the UK, my fibre connection.

hio77

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#1612117 15-Aug-2016 18:43

ctucks:

Yeah...

VDSL is so frustrating! It's bad enough that we're not that close to the exchange, I think there is a closer cabinet to us that we're not connected to. Our downstream line attenuation is like 25db! I hope fibre comes sooner rather than later, that's one thing I miss about living in the UK, my fibre connection.

VDSL is purely an stepping stone, fibre is the future.

MDF layouts aren't always logical in a distance situation.

#include <std_disclaimer>

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

coffeebaron

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#1612164 15-Aug-2016 19:36

Do you have a master filter installed?

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