Router stats - DMT result

I'd appreciate any comments on the DMT results shown below :-

Counters Down Up

SF: 3029671 3029669
SFErr: 0 1351
RS: 110583022 12876093
RSCorr: 106 187786
RSUnCorr: 0 0

HEC: 0 3986
OCD: 0 0
LCD: 0 0
Total Cells: 262896973 1220813143
Data Cells: 481471 5033106
Drop Cells: 0
Bit Errors: 0 212242

ES: 0 324
SES: 0 56
UAS: 30 1472

Total time = 18hours 55min 50sec
SF = 4197645 CRC = 0
LOS = 0 LOF = 0 ES = 0

Latest 1 day time = 18hours 55min 50sec
SF = 4197645 CRC = 0
LOS = 0 LOF = 0 ES = 0

Previous 1 day time = 0sec
SF = 0 CRC = 0
LOS = 0 LOF = 0 ES = 0

Router has been connected to test socket for at least 24 hours, laptop connected via ethernet.
Problem I'm having is downstream bitrate, used to be 6656 consistently but now it's been 2268 for a couple of weeks, any ideas ?

Could you post your router stats as well?

http://www.dslzoneuk.net/adsl_line_stats.php

System Date and Time
Date/Time May 12 2008 , 13 : 05 : 36
Runtime Code version F5D7633-4Av1_UK_1.00.000
Boot Code Version 1.0.37-5.15
Firewall EnabledNAT Enabled Channel 11
UPnP Disabled Security WPA-PSK

ADSL
Type
Status No Defect
Downstream Upstream
Data rate 2268 285
Noise margin 24.9 18.7
Output power 20.2 11.7
Attenuation 41.0 20.2

Although it doesn't show on the router stats, DMT shows that Interleave is ON. Normally TYPE = FAST but it's now blank.

This is taken from the test socket

Connection is fine with no dropouts.

You don't seem to be connected to an ISP that uses BT kit. Normally BT ISPs data rates, up and down, are multiples of 32kbps.

Does your ISP use LLU?

Your SNR margins (24.9/18.7) seem very high.

I won't "name names" yet but yes it's LLU.

And I believe they're trying to switch over to ADSL2+ (but they won't confirm that)because that's what the full DMT data shows me.

DMT also indicates Interleave depth is set at 32 down 8 up.

Well the reason your downstream sync is so low is because of that huge noise margin. What happens if you resync? If it is the same then either the router is ready for the bin or you have been set a huge target margin.

You keep mentioning DMT - is this the DMT software which allows target margins to be tweaked? If so then that is probably your answer - you've shot yourself in the foot by playing around with something you didn't understand. If not then it's router or ISP - it isn't the line because my betting is that with a 6dB margin that sync would be right back where you said it was originally.

Edited by kwikbreaks (Mon 12-May-08 14:09:48)

I'm not familiar with DMT so can't really interpret what it is saying. The normal target SNR margin (up and down I think) is 6dB. As the target is raised there is a corresponding drop in achievable sync rate. The only reason to increase the target from 6dB is to stabilise the line. The higher the SNR margin the lower the number of errors.

It would be useful to know how many downstream FEC/HEC/CRC errors you get in a normal day.

Correct re. DMT......but I've not "played around", I'm only using DMT to monitor not tweak because it gives more data than the router stats.

Eg, errors and the fact that Interleave is on and the depth and also that the connection is ADSL2+.

Resyncing does nothing. Occasionally SNRM drops to low 20s but that all.

When it synced at 6656, SNRM was around 11 and attenuation 39.5.

As a matter of interest is your phone line noisy?

What happens if you do the BT quiet line test (17070 option2 I think)? If you don't have a BT line this won't be possible.

I've tried 17070 and no it's...................absolutely silent.