A Chronicle of My Migration and Problems

[#1]

The new router turned up and was a Netgear DG834UK (V4), not the V5 that they said was.
Still, I'm happy with that - at least it's a proven release.

[#2]

H'mm, not so sure about the last post......
Although the label on the router says V4, when I've installed this and had a look at the frirmware version it says V5 something or other.
However, the Netgear router is now up and running. (well, for the past hour or so)
I have just managed to get RouterStats running too (could only use RouterStats light on the Linksys)
Now it might just be me, and it is early days yet, but the Linksys was showing a NM of about 10 before I switched it off to fit the Netgear.
RouterStats is showing the Netgear with a down NM of 6.3 to 6.5 at the moment and an up of 6.3
The sync speed has not changed much though - showing as 9726 instead of 9725
The Linksys was also showing (according to RouterStats Lite) fluctuations of NM between 8 and 11, whereas, at the moment the Netgear is showing marginal fluctautions in the order of of 0.1 or 0.2 as indicated above.
Is there anything else that I can get access to now that I have got the full version of Routerstats installed and running?
Let's leave this for now - it's nearly 2am and I have to get up for work in the morning.
Graham

[#3]

The current firmware version for the DG834V4 is V5.01.14, I think it is V6.x.x for a V5. However the Netgear support website doesn't mention a V5 for the non-wireless product so possibly there isn't one. I regard being a V4 is good news.
Onto Routerstats. As you seem to have found, it is easy to configure it for this router. I think it automatically detects the Version on most pages, but occasionally it is necessary to select V4. You should be able to access the more hidden information by enabling Routerstats' telnet interface. This is done via the Experimental Settings tab on the Configuration -> Telnet tab (make sure you mark the V4 radio button on this page). A Telnet Router tab will then appear on the main display page. The various tabs that gives should include one showing the Bits and SNR per Tone, which can be illuminating.
One of the tabs is for Setting Target SNR; tinker with that at your peril. From the experience posted by others I think it is fair to say that doing so confuses the DLM and it can take a long time for it to forgive your indiscretion and react normally.
In fact leaving things alone is my suggestion for the moment, let's see what the DLM makes of the new configuration. It would be interesting to see the full router stats from the Netgear and SNR history daytime and after dark.
David

[#4]

Well it would appear that the DSM didn't like me changing routers............
Switched on PC tonight to see that down sync was down to 5689 and originally the NM was 6.
Just after 10.00 pm the NM shot up to 19.5 and it is currently hovering around 19.
I've also got DMT installed and working, so if there's any info hidden in there please let me know what to look for

[#5]

The upstream bits plot looks reasonable but downstream is peculiar, shouldn't have the large dips centred around tones 113 and 200. that is possibly where your speed disappears to (so to speak) even when the target noise margin is lower.
For the moment I think the way forward is to let the DLM get on with its line management activities. Increasing the target noise margin as it has done seems to be part of its logic and before long (can be 7 to 14 days) it should come down again. Looking at the bits/tone plot again would then be useful - a similar shape to the present one could indicate a broadband fault.
I don't think DMT gives more information than Routerstats for the DG834V4, some regard the plots from DMT as easier to read. It's not a program I am very familiar with.
David

[#6]

Following advice from the "techies" (there is a ticket open on this and has been for a while) I have done a hard reboot of the router and this has brought the NM back down to 6.1 at present. They advised to download and install the latest firmware (5.01.14) but the router already has this installed and I couldn't see any point in installing a downloaded version and having to reconfigure the router again.
I guess we wait and see again. (for 3 days the techie said)
The chap from PN who phoned me also said that PN are having many discussions with BT regarding the agressiveness of the DLM and it's slow response to put NM back up. It doesn't sound as if they are getting anywhere, which is strange as BT own PN, (not something that is shouted out in the public domain) so you would have thought that one would co-operate with the other 
Maybe it's because it would BT cost such a lot of money to "reprogram" all those DLM's to bring NM up faster, and nothing to do with operating at the best setting?
Anyway, here's the current figures:

[#7]

Here's a quick look at the RouterStats as at 00.45 on 24/5/09 (downstream first):
Noise Margin:    4.3  dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:        16016  Kbps

SF:              1642311
SF Errors:        28
Reed Solomon:    1405818428
RS Corrected:    175999
RS Un-Corrected:  838
HEC:              18
Errored Seconds:  18
Severe ES:        0
Interleave Depth: 128

Noise Margin:    4.3  dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:        16016  Kbps

SF:              1642311
SF Errors:        28
Reed Solomon:    1405818428
RS Corrected:    175999
RS Un-Corrected:  838
HEC:              18
Errored Seconds:  18
Severe ES:        0
Interleave Depth: 128

[#8]

The post is actually 2 lots of the downstream values - I guess you are just seeing if we are paying attention.

[#9]

OOPS !
Well here it is as of 9.40 on 24/5:
Noise Margin:     5.3   dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:         16744  Kbps

SF:               3638543
SF Errors:        34
Reed Solomon:     3114592946
RS Corrected:     348552
RS Un-Corrected:  962
HEC:              24
Errored Seconds:  24
Severe ES:        0
Interleave Depth: 128
Noise Margin:     5.7  dB
Connection Rate:  1220   Kbps
Line Attenuation: 14.8  dB
Power:            13.0  dBm
Max Rate:         1216  Kbps

SF:               3451488
SF Errors:        0
Reed Solomon:     833777
RS Corrected:     0
RS Un-Corrected:  0
HEC:              0
Errored Seconds:  0
Severe ES:        0
Interleave Depth: 4
I have left the PC on all night so that I could get a "bigger picture" of behaviour.
Looking at the plot, it's like watching a bad movie; nothing much happens.
Noise margin dropped about 10 pm from ~6 to ~4.5 and then slowly went down to ~4 at about 2am, then slowly crept back up to ~5 at about 5am. At about 6am it jumped slightly to 5.3 at which is has remained (give or take 0.1) till now. Sync speed 9721.
At one stage Saturday night (8ish?) when I checked the telnet data, the level of down "interleave depth" was a whopping 384 and 64 on up.
As you can see above, it's gone down a fair amount, but I still think 128 for the down is a bit of overkill.
It may be that a down NM of 4 is a bit too low for the line and maybe if it creeps up to 6 then the HEC and other errors will go away.
BTW - Who's this Reed Solomon who's sticking his two-pennorth in? 
Graham

[#10]

Reed and Solomon are the guys that developed the overdetermined polynomial codes that are used for transmission error correction. The scheme is also used on CDs, but has a lower profile there. On ADSL it is usually used in conjunction with interleaving. I think the larger interleaving depths you mentioned imply the system is on auto and was coping with long bursts of noise at the time. I guess it is too much to hope you noticed any "noise generators" in action at that time (e.g. flashing internal or street light)?
The present download interleaving depth of 128 is double the usual 64, but maybe implies the system is still coping with noise - probably the reason for your sync speed being lower than it should be at your attenuation and the hollows in the bits/tone plots. Do those look any different now from before?
David

[#11]

Yes, I did read up about Reed Solomon.
But I still don't know what the figure in the router stats is trying to tell me.
The latest (today at 10.05 -ish) tones plot is attached.
Summary:
Noise Margin:    5.2  dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:        16632  Kbps

SF:              9100964
SF Errors:        133
Reed Solomon:    3495458462
RS Corrected:    1120087
RS Un-Corrected:  2596
HEC:              95
Errored Seconds:  96
Severe ES:        0
Interleave Depth: 128
Noise Margin:    5.5  dB
Connection Rate:  1220  Kbps
Line Attenuation: 14.8  dB
Power:            13.0  dBm
Max Rate:        1216  Kbps

SF:              8628060
SF Errors:        0
Reed Solomon:    4224360
RS Corrected:    0
RS Un-Corrected:  0
HEC:              0
Errored Seconds:  0
Severe ES:        0
Interleave Depth: 4

[#12]

There have been a few "drops" during today - 3 at approx 14.00, 14.23 and 14.49 - then another at 17.54 and another at 21.09. Sync speed came back at the same rate as prior to the drop and at the same NM  too.
I have attached one image showing the drops around 1400/1423
Current summary is:
Downstream:
Noise Margin:     4.5   dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:         16132  Kbps

SF:               11734763
SF Errors:        293
Reed Solomon:     1455022828
RS Corrected:     1517013
RS Un-Corrected:  22076
HEC:              233
Errored Seconds:  168
Severe ES:        1
Interleave Depth: 128
Upstream:
Noise Margin:     6.0  dB
Connection Rate:  1220   Kbps
Line Attenuation: 14.8  dB
Power:            13.0  dBm
Max Rate:         1224  Kbps

SF:               11124687
SF Errors:        0
Reed Solomon:     2723503
RS Corrected:     0
RS Un-Corrected:  0
HEC:              0
Errored Seconds:  0
Severe ES:        0
Interleave Depth: 4
Download speed is screwed though 

Yes, that does say a download speed of 130kbps and an upload speed of 1028kbps
Bt's test also shows a similar result:
Test1 comprises of Best Effort Test:  -provides background information.
    Your DSL connection rate: 9720 kbps(DOWN-STREAM),  1220 kbps(UP-STREAM)
    IP profile for your line is - 8000 kbps
    Actual IP throughput achieved during the test was - 83 kbps

Graham

[#13]

Does the current line speed in the Member Centre still say 8000kbps (can't imagine why it would differ from that)?
I suggest recording the downstream errors, doing a speedtest then recording the downstream errors again. Since there shouldn't be any traffic shaping on HTTP/speedtest data I'm making the assumption that only errors could cause so much slow down.
This "constant sync speed" syndrome seems to be reported by several users - though Asbo has just managed to find the escape door.
David

[#14]

Hi David,
Yes the PN speed profile is still saying 8000.
I tried the before and after test:
Before speed test
Noise Margin:    4.6  dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:        16252  Kbps

SF:              16940614
SF Errors:        439
Reed Solomon:    1616264118
RS Corrected:    2756252
RS Un-Corrected:  26030
HEC:              350
Errored Seconds:  251
Severe ES:        1
Interleave Depth: 128

After speed test
Noise Margin:    4.6  dB
Connection Rate:  9721  Kbps
Line Attenuation: 32.0  dB
Power:            0.0  dBm
Max Rate:        16176  Kbps

SF:              16949639
SF Errors:        439
Reed Solomon:    1623989860
RS Corrected:    2757181
RS Un-Corrected:  26030
HEC:              350
Errored Seconds:  251
Severe ES:        1
Interleave Depth: 128

As can be seen there are quite a few RS corrected errors (929) but nothing else logged.
The speed test still gives:

The down NM is still showing as 4.5 and sync speed is 9721 (as above)
Up NM is 6.1 and sync speed 1220.
It's 3 days since I last contacted the techies, so I'm going to pass these figures over to them to have a look at.

Graham

[#15]

Yes, I think passing them to the faults team has to be the way to go.
David