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[JBAR]

Hi

When I returned home after a two week break earlier this year I discovered that my Netgear DG834v3 router had locked up. Prior to going away, the router was happily syncing at speeds around 5.4Mbps (on a target SNR of 9db) giving me a stable IP download profile of 4.5 Mbps. Initially, it was a real battle to get any sort of stable connection back but after a month or so stability was achieved. The issue is, that while the connection for the last two months has been stable, I have never synced at a speed above 4.7Mbps and my target SNR seems stuck on 12db. This despite the fact that my router often lasts up to 10 days before a re-sync. I have tried asking BT to lower my target SNR to 9 but to no avail. I would have thought in any case that the target SNR would have automatically lowered to 9 by now? My router is on the latest UK firmware (4.01.30)and my current connection details are as follows :-

Downstream

Connection Rate:  4704 Kbps
Line Attenuation: 46 dB
Noise Margin:     12 dB

Interleave CRC:   0
Interleave FEC:   0
Interleave HEC:   0

Fast path CRC:    3871
Fast path FEC:    0
Fast path HEC:    0

Upstream

Connection Rate:  448 Kbps
Line Attenuation: 29 dB
Noise Margin:     23 dB

Interleave CRC:   0
Interleave FEC:   0
Interleave HEC:   0

Fast path CRC:    30
Fast path FEC:    2924
Fast path HEC:    0

[kitz]

Hi

You are correct in assuming that its the higher Target SNR that is keeping your sync speeds lower.
All I can imagine is that whilst you were away there must have been a bad period of time (eg thunderstorms) which may have caused some instability and caused the router to loose sync and the DLM to increase your Target SNR.

The theory is that after a few weeks then the DLM should lower your target SNR back down again, but theres various factors to this, and it doesnt always seem to follow any particular fixed method.
The line has to remain stable, but I believe it also looks at your error count.

From the stats provided the errors look acceptable but I dont know how long the router had been up for when you took those stats.


Make sure that you have done all the usual things yourself to try and make the best of your line

http://www.kitz.co.uk/adsl/socket.htm
http://www.kitz.co.uk/adsl/lowSNR.htm


If the line remains stuck at the higher target SNR, then Im afraid its a case of battling it out with your ISP to get it lowered...  or using a router on which you can do this yourself.

[JBAR]

Hi kitz

Thanks. Yes, I already have implemented the suggested changes. Interesting that you suggest I might change to a router where I could manipulate the target SNR; I was considering a Netgear DG834v4 or a Thomson TG585v7. How effective is it in practice? I read somewhere that it could lead to the DSLAM and router 'fighting' with each other?

[kitz]

Works for a lot of people

Just be careful with the Speedtouches though...  Thompson have removed the ability to be able to do this is their later models.. and latest firmware versions for some of their older routers. Firmware version 6.1.4.3 is that last version that the SNR tweak will work with on the v6 routers.

With some of the other broadcom routers ie Voyager 2100/2110/2109 /210 Netgear dg834gt and dg834g v4 it works but its not a permanent change,... although I believe one of the custom firmwares such as Uberfirmware makes this an option.

[Ezzer]

upstream errors are a clue that some noise has poped up from your premises end at some time, Storms can do this and so this should only pop up occasionaly. if this keeps appearing then this suggests some noise issue nearby which has caused your snrm to go up and unless this is resolved then getting your target snrm reset would only work short term and will revert to what you have now again

[JBAR]

Hi ezzer

I wondered if my router stats pointed to a local noise problem. My current connection has been up for just over three days and my upstream error count is :-

Fast path CRC:    120
Fast path FEC:    3944
Fast path HEC:    408

I have made just about every modification I can think of to my local environment; a filtered faceplate on my master socket, a ferrite on each power adapter lead (the router shares an extension lead connection with a DECT phone) and a shielded ADSL lead. I have just ordered a Netgear DG834Gv4 though (so I can adjust my target SNR) and I'll be interested to see if it improves the noise situation.

[Ezzer]

The errors are no problem if the're evenly spread out

What I look for during a 5 min test for non interleaved <60-100 crc or hec errors

interleaved switched on <1000 crc/hec errors, rs errors <14,000