Kitz Forum

Broadband Related => Broadband Hardware => Topic started by: silentshark on September 09, 2017, 10:55:26 AM

Title: Advice to squeeze out some more speed from my VDSL line.
Post by: silentshark on September 09, 2017, 10:55:26 AM
Hi gurus,

I am looking to squeeze some more speed out of my Zen VDSL connection (their fibre1 package - up to 38Mb down, up to 9.5Mb up). Hardware today is HG612 modem and and RT-AC68U wireless combo. The 'box in the street' is huawei, and is about 800m away (at a guess). It all works quite well. But we are a bandwidth hungry household and use a lot of data, so more speed would be good.

I'm currently getting 32400 down, 6966 up. Attached is a png of more stats on my line.

Any advice from the clever folks on this forum would be helpful.. Would moving to something like a VMG8324-B10A with the BCM63168 chipset maybe buy me a few more Mb?

Many thanks in advance for any advice, thoughts etc :)

Title: Re: Advice to squeeze out some more speed from my VDSL line.
Post by: broadstairs on September 09, 2017, 12:14:52 PM
I have used both VMG8324 and VMG8924 (latter has 2.4ghz and 5ghz wi-fi), and both were OK. I now have a VMG3925 which I find much better than either previous ones although it has a few less features it does seem much better with lower error rates and has 2.4ghz and 5ghz wi-fi. Not sure any of these are going to significantly increase your sync speed though.

Stuart
Title: Re: Advice to squeeze out some more speed from my VDSL line.
Post by: Ixel on September 09, 2017, 12:37:44 PM
I don't know what RJ11 cable you use or how long it is, but if it's a flat cable that's reasonably long and you can do with a shorter cable then maybe a better quality twisted pair cable would help get a little more speed and slightly better resistance to errors.
Title: Re: Advice to squeeze out some more speed from my VDSL line.
Post by: j0hn on September 09, 2017, 01:19:08 PM
Your line is banded (capped) at 32.4Mb
Nothing you do will increase that unless the banding is removed.
Title: Re: Advice to squeeze out some more speed from my VDSL line.
Post by: silentshark on September 09, 2017, 01:29:53 PM
Your line is banded (capped) at 32.4Mb
Nothing you do will increase that unless the banding is removed.

aha, I'd wondered about this. How can you tell it's banded? Is there anything I can do to get the banding removed?
Title: Re: Advice to squeeze out some more speed from my VDSL line.
Post by: j0hn on September 09, 2017, 04:05:00 PM
The exact sync figure of 32400 is 1 of the banding figures OpenReach use. That and the SNR Margin being as high as it is (the target is 6) points to the line being banded.
Banding usually syncs at an exact figure like 54,000, or 53,999.

It should remove itself. We see quite often that it gets stuck in that state. If it doesn't remove itself then it would require an OpenReach engineer to perform a DLM reset to remove it.

Do you know how long the line has been syncing at that figure? Have you had any burst of Error Seconds on the line recently, any faults, or any time where you have resynced a large number of times in a short period of time? These can all cause the banding to be placed.

This page (https://community.plus.net/t5/Library/FTTC-DLM-What-it-is-How-it-works/ba-p/1322799) lists some of the banding levels, though I've seen lines banded at other figures too. Your line looks like it's on the 16.2 - 32.4Mb profile.

Regarding the original question, I own both a Zyxel VMG8924-B10A and a Zyxel VMG1312-B10A. Both devices use the BCM63168 chipset, which is best on my line.
The Zyxel VMG1312-B10A syncs slightly higher on both upstream/downstream on my line and is usually considerably cheaper than the VMG8x24-B10A.
My 8924 has extremely low upstream power compared to the 1312, knocking upto 1Mb off my upstream.
Title: Re: Advice to squeeze out some more speed from my VDSL line.
Post by: silentshark on September 09, 2017, 04:37:19 PM
It's been stuck on that state for a long time, since last year.

There are some error seconds logged on the upstream - 1107 total for the last 10 days, and 0 on the downstream. I have more data from the Ronski's modem stats program if that would aid diagnosis.

I haven't resync'd a large number of times - it's probably resynced 6 times this year. Way back in 2015 we had an internal wiring issue, where the main telephony cable inside the house needed replacing. Back before this issue we had 32Mb downstream, then for a while following the fault we were down to 22Mb. Back in Jan 2016 it jumped back to 32Mb downstream. And it's been there ever since. Some data from the zen portal is attached.

I'm far from an expert on this stuff, but I'd hope that some more can be squeezed from the line given the high-ish SNR.

What could be my next step? Do Zen help with things like this?

PS thanks for the pointers and the info on your Zyxel stuff. Sounds like I should stick with my 'as is' hardware whilst I have this banding thing in place.