ADSL Stats Advice

axer · 22 Apr 2013 at 10:17

I'm temporarily living with the in-laws whilst some major refurbishment work is carried out on a house I recently bought. Once we move, I'll not have any internet problems as a private leased circuit is going in (whoop!) but untill then I'm stuck with AOHell DSL.

The in-laws internet has never been stable despite a veriety of recent changes made by AOL/BTOR such as a replacement router, replacement microfilters and moving the primary phone socket.

In short, *something* seems to die quite regularly (e.g. every few hours) although is relatively quick (~30s) to fix itself but what ever resets seems to result in an IP change which is proving to be a PITA.

I've logged into the router (Huawei) and here are the DSL line stats:

http://www.axerite.com/jing/2013-04-22_1011.png

Not that the DSL circuit is showing as 18hrs uptime yet the net dropped about 5 minutes ago which has me scratching my head!

Any thoughts people?

Locky · 22 Apr 2013 at 10:23

There looks like a fault 65k crc erros in 18 hours is high and 16.7db snr also points to a fault with the line.

The line also has high interleave depth which points to a fault somewhere on the line.

axer · 22 Apr 2013 at 10:29

Hi Locky,

Thanks for your response, what sort of snr should I be seeing typically?

Regards, Jon

axer · 23 Apr 2013 at 13:42

I fitted an I-plate to the socket today which may have slowed down the errors, here are the error stats so far:

@ 12:35 on 23/04/13:

Downstream CRC 65504
Upstream FEC 429
Downstream FEC 65444

@ 13:40 on 23/04/13:

Downstream CRC 65504
Upstream FEC 466
Downstream FEC 65444

axer · 23 Apr 2013 at 13:47

Interestingly the i-plate seems to have increased the speed to:

Before:
http://www.axerite.com/jing/2013-04-22_1011.png
http://speedtest.net/result/2657889863.png

After:
http://www.axerite.com/jing/2013-04-23_1343.png
http://www.speedtest.net/result/2664264278.png

Whether the stability has increased remains to be seen

Tealc · 23 Apr 2013 at 15:53

With that line you should be hitting 20Mbit if all is working ok.

SNR is normally around 6-7dB but can depend on ISP settings.

axer · 23 Apr 2013 at 16:07

A couple of hours on and I see:

@ 15:40 on 23/04/13:

Downstream CRC 65504
Upstream FEC 1621
Downstream FEC 65444

I'm not sure how significant or not the increase in Upstream FEC is

Tealc · 23 Apr 2013 at 16:26

FEC errors are fine and is something to do with Interleaving.

Kitz said:
Count of errors that have been corrected due to error correction being applied to the line. Error correction is turned on at the same time as Interleaving. Its normal to see FEC errors on an Interleaved line and rather than anything to be too concerned about its more an indication that the Interleaving & Error Correction process is working and doing what it should. - See Error Correction for more information.

More info http://www.kitz.co.uk/adsl/linestats_errors.htm

It's HECs and CRCs you have to be aware of.

axer · 23 Apr 2013 at 16:38

Doh, thought I was making progress as to what the issue might be, back to the drawing board then!

axer · 24 Apr 2013 at 11:37

These are the latest stats from my line, what are we thinking guys, any obvious signs of an issue?

@ 17:51 on 23/04/13

Downstream CRC 65504
Upstream FEC 3788
Downstream FEC 65444

@ 23:10 on 23/04/13

Upstream CRC 11
Downstream CRC 65504
Upstream FEC 10004
Downstream FEC 65444

@ 11:36 on 24/04/13

Upstream CRC 23
Downstream CRC 65504
Upstream FEC 16389
Downstream FEC 65444