Here are some VDSL Line Stats...

Seeing as I've haven't seen anything published, I thought I'd post my VDSL line stats for comment. btw, you can't get these from the BT supplied device, you need a device such as the Thomson TG789n to do this. I bought mine from ADSL24, after having some nightmares (a few weeks back) with my connection and wanting to see what was going on.

Uptime: 0 days, 22:23:27
DSL Type: ITU-T G.993.2
Bandwidth (Up/Down) [kbps/kbps]: 9,999 / 19,994
Data Transferred (Sent/Received) [kB/GB]: 0 00 / 2
Output Power (Up/Down) [dBm]: 3.2 / 9.2
Line Attenuation (Up/Down) [dB]: 0.7 / 0.1
SN Margin (Up/Down) [dB]: 9.1 / 6.1
Vendor ID (Local/Remote): 0F00TMMB3C61 / 0000----0000
Loss of Framing (Local/Remote): 5 / 0
Loss of Signal (Local/Remote): 4 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 1 / 0
FEC Errors (Up/Down): 636,661,366 / 14
CRC Errors (Up/Down): 5,531 / -
HEC Errors (Up/Down): 26,646 / 0

Download sync speed drops to around 15megs at busy times such as weekends.

btw, I am around 500m of road from the cabinet.
I am subscribed to a 40/10 meg service.

Any comments on the stats?
# Obviously, the data transferred looks wrong, down to the modem firmware I expect.
# Line attenuation looks very, very low.
# SNRs don't look very good to me.

Steve

Edited by vdsl_steve (Mon 31-Jan-11 13:05:40)

Lots of errors too

Whats the in property phone wiring like, does removing all the telephone wiring, i.e. lower half of master socket make a difference to the stats.

The actual sync speed goes down at busy times? Not just the throughput?

Don't forget the attenuation is measured from the cabinet, not the exchange. But wierd even so with the upstream being so different and higher.

Can you get details of the attenuation at the different freqencies? And I wonder where the upstream ones are in relation to the downstream.

Noise margins look fine to me. What worries you about them?

Edited by RobertoS (Mon 31-Jan-11 12:43:17)

Hi Andrew,

Thanks for the reply.

I removed the phone connection from the master and rebooted the modem.
I got 9.1/10.3 dB.
I then plugged the phone connection back in and rebooted again.
I got 9.1/10.2 dB.
So whilst the SNR went up, that pretty much concludes it was only due to the reboot.
Phone wiring is all on CAT5 with RJ-45 LUAs in each room.
Output powers did not vary. Neither did sync speed.
Btw, there are no punched down extensions inside the master. So the VDSL was the only connection.

Best regards

Steve

Your upload looks nice!

>The actual sync speed goes down at busy times?
>Not just the throughput?
>
Yes. Confirmed with BT SpeedTester. The Download Profile changes.
Consequently the throughput also changes.

>Don't forget the attenuation is measured from the cabinet, not the exchange.
>
Yes. That is what the FTTC service is.

>But wierd even so with the upstream being so different and higher.
>
Upstream is likely to be higher as the upstream data runs on the lower frequencies of the link.
With a 10 meg uplink, the downloads are pushed much further up the frequency spectrum than with a 256k uplink.

>Can you get details of the attenuation at the different freqencies?
>
No facility for that on this router sadly.

>And I wonder where the upstream ones are in relation to the downstream.
>
See above.

>Noise margins look fine to me. What worries you about them?
>
6 dB is marginal. And I am only 500m of copper from the DSLAM. My sync drops in busy times to 15meg and I paid for 40 meg. If 15 is all I can reliably get, then fine, but I don't think things are quite right.

Cheers

Steve

I paid for 40 meg

you paid for a service that can go at up to 40M on lines capable of that. Price isn't a function of speed

If you read the whole sentence, you'll see I said I am happy with 15 Meg, if that is all my line can support. But that is not the purpose of this post.

This post is just meant to be some interesting reading, as there aren't many sets of line stats out there for VDSL just yet. I am hoping some people with some knowledge of VDSL might shed some light on the numbers, as they don't look like any ADSL figures I've ever had. E.g. When did you last see attenuation of under a decibel, with an SNR of less than 10?

Steve

P.S. Did you mean 'speed isn't a function of price' ?

Do you have a link for this router/modem?

I can't see it on their website and when I called them they seemed to know nothing about it?!?

Here it is...

https://adsl24.co.uk/store/ADSL-Modem-Routers/ADSL-W...

Cheers

Steve