Router Resync at low speed: Why? At a loss

Hi gang, looking for some advice please

About a year ago I switched from Pipex to Plusnet and, to resolve some issues I was having with disconnects, rewired my master socket with the XTE-2005 faceplate. (I'm on Plusnets Broadband Your Way package if that's important)

This improved things for me no end and I went to a pretty stable stable connection of around 2.5mg (I had only ever managed 1 mg before).

I'm using a Netgear DG834GT Router. Plugged into the downstairs master socket (XTE 2005) and wirelessly connected to my PC upstairs to avoid reconnecting the internal extension wiring . My "usual stats" are:

Downstream
Connection Speed 2784 kbps
Line Attenuation 55.0 db
Noise Margin 11.6 db

This gives me a 2500kpbs line profile with Plusnet. Happy with that (well, not really but i'm on a long line so have to be..)

However, over the last few weeks I've noticed that my speeds have been dropping to sub 1mg and I've been getting some disconnects again - not many, but enough to be a pain. Doing some checks showed that my router sync was now around 1024 kbps and therefore my profile with Plusnet is downgraded to between 750kpbs and 1mg.

My router stats at these times show this type of profile:

Downstream
Connection Speed 1024
Line Attenuation 56.0 db
Noise Margin 16.3 db

So the real noticable change, other than the sync, is the the noise margin increase.

I've rebooted my router several times over the last few days. Each time the stats go back up to the "norm". However, at some point during the day or night (haven't been able to pinpoint this) my router obviously resyncs and drops my stats again. This means that, as I'm on MAX, my line profile with PlusNet is never upgraded.

I'm aware that different household equipment can effect things so I've done some tests today - running around switching things on an off. I have therefore checked my router stats with every possible piece of electrical equipment. (battery and phone chargers, TV and sky, using phone and mobiles, lights, fridge, washing maching, hoover, etc.. etc... even the central heating, boiler and power showers). To really test things out I've even put everything on at once and switched things on and off at random.

None of this had any effect on my line stats.

So what else could be the reason for my router resyncing at such bad speeds and high noise margin?

I'm at a loss what to do.

Please help! Quick thought - perhaps the Netgear router is not a good router for long lines?

In reply to a post by Discord:

So what else could be the reason for my router resyncing at such bad speeds and high noise margin?

BT have a system which is supposed to respond to multiple re-syncs within a short time frame.
It tries to correct the stability issue by increasing the target noise margin (the one your router aims for, when connectin). The default target is 6dB, but BT's systems will increase this in 3dB steps (up to a maximum of 15dB) every time it thinks you've suffered too much instability.
Unfortunately, it sometimes acts a little too aggressively (I once had a margin increase from 12 to 15dB following a single re-sync).
For every 3dB additional margin, you can expect to lose around 500-800kbps off your connection speed.

As you've such a high margin, there really shouldn't be anything to cause sudden re-syncs.
So you can gain a little bit of speed, by manually resyncing during daylight (around 11am seems to be the best time), when there's not much background noise, so you'll get the highest connection speed for your given margin.

Long term, if you leave your router alone (and don't switch it off), and your connection becomes more stable (and virtually error free), the same BT system is supposed to drop your margin by 3dB every two weeks.
Unfortunately, it hardly ever works.

You could ask your ISP to request BT lower your margin (6dB should be OK on a 55dB line, unless it's fed by overhead wires when 9dB might be more appropriate), but BT often refuse (or ignore these requests), and that's assuming Plusnet know what you're talking about.

Normally, the only way out of this is to kick BT wholesale into touch, and go with Sky, UKonline, BE or O2 unbundled products.

There is a last resort (if BT refuse to play ball) - Get yourself a tweakable router, and DMT, and tweak your margin back to 10dB yourself (about the most you can go with Broadcom DSL chipsets).
Or, get a Billion 5200G and the right version of firmware (this, reportedly, forces sync at a 6dB margin, and ignores any stupid BT enforced punishment margins).

Edited by adebov (Sat 14-Feb-09 16:56:49)

Thanks for the detailed response abe. That's given me a few avenues to explore.

I've also got my hands on an app called "routerstats" that means I don't have to keep checking and recorded my stats. That could also be a lifesaver - certainly a massive time saver.

USing the router stats prgramme I can see that after a few hours of "stableness" I started to get probs.

Effectively, no connection between 19:12 and 19:22. There was nothing going on in the house that I can think that would have caused this.

Interstestingly though, the router resyncs at the same speed.

Sat 14 Feb 2009 19:06:12, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:06:27, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:06:42, Noise Margin= 11.8, Sync Speed= 2784
Sat 14 Feb 2009 19:07:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:07:14, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:07:27, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:07:42, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:07:57, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:08:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:08:30, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:08:42, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:08:57, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:09:12, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:09:27, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:09:42, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:09:57, Noise Margin= 11.3, Sync Speed= 2784
Sat 14 Feb 2009 19:10:12, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:10:27, Noise Margin= 11.8, Sync Speed= 2784
Sat 14 Feb 2009 19:10:42, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:10:57, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:11:12, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:11:27, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:11:42, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:11:57, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:12:12, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:12:27, Noise Margin= 11.8, Sync Speed= 2784
Sat 14 Feb 2009 19:12:45, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:12:56, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:13:11, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:13:26, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:13:41, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:13:56, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:14:11, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:14:26, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:14:41, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:14:57, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:15:12, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:15:27, Noise Margin= 11.3, Sync Speed= 2784
Sat 14 Feb 2009 19:15:42, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:15:57, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:16:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:16:31, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:16:45, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:17:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:17:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:17:30, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:17:45, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:17:58, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:18:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:18:30, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:18:45, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:19:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:19:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:19:28, Noise Margin= 11.6, Sync Speed= 2784
Sat 14 Feb 2009 19:19:45, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:20:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:20:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:20:30, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:20:45, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:21:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:21:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:21:30, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:21:47, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:22:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:22:17, Noise Margin= 11.5, Sync Speed= 2784

Having used Routerstats, quite extensively, I think you're seeing evidence of its occasional problems obtaining data (particularly if it has to do so, via the router web-interface).
It's extremely unlikely to have this many re-syncs, when the margin is 11-12dB, and for all of them to be at exactly the same speed.
I would say you're just seeing gaps in the logging.
Keep monitoring, but watch out only for sync speed changes.

EDIT: As you're using a Netgear DG834GT, you can also use DMT v8.07 to monitor (although you may have to switch on the telnet server in the router).
DMT allows you to view much more information, and the image grabs (showing bit loading, SNR per tone, etc.) are very useful.
Let us know if DMT brings nothing back, and someone will come on with the telnet enablement string (I've got a record somewhere).

Edited by adebov (Sat 14-Feb-09 19:50:13)

Isn't it possible that theres a little HR-ish type noise on the line ? Worth the OP doing a quiet line test with a decent corded phone ?

Hi again.. you've lost me a little with the DMT and Telnet thingies. But I'll check it out if I need. I think you're wrong though.. It's not Routerstats missing items in the log, I've just been working on my computer and again lost my connection for about 5 mins. Checked the routerstats log and it confirmed - no sync between 19:58 and 20:03 (below)

I've also been looking at DGTeams firmware, but think I'll leave well alone!

I think I'm going to have to raise a ticket with Plusnet and will no doubt ultimately have to get BT involved. I''m 2miles from my exchange (straight line) but shouldn't have these sorts of problems.

Sat 14 Feb 2009 19:57:15, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:57:30, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 19:57:45, Noise Margin= 11.5, Sync Speed= 2784
Sat 14 Feb 2009 19:58:00, Noise Margin= 11.3, Sync Speed= 2784
Sat 14 Feb 2009 19:58:19, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:58:34, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:58:49, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:59:04, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:59:19, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:59:34, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 19:59:49, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:00:04, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:00:19, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:00:34, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:00:50, Noise Margin= 11.2, Sync Speed= 2784
Sat 14 Feb 2009 20:01:04, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:01:19, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:01:34, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:01:49, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:02:04, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:02:19, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:02:34, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:02:49, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:03:00, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:03:15, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:03:30, Noise Margin= , Sync Speed=
Sat 14 Feb 2009 20:03:45, Noise Margin= 11.4, Sync Speed= 2784
Sat 14 Feb 2009 20:04:00, Noise Margin= 11.3, Sync Speed= 2784
Sat 14 Feb 2009 20:04:15, Noise Margin= 11.3, Sync Speed= 2784

In reply to a post by Zarjaz:

Isn't it possible that theres a little HR-ish type noise on the line ? Worth the OP doing a quiet line test with a decent corded phone ?

There's certainly something odd going on, and (as you know) the margin doesn't go up to 15dB for nothing (it's often a little keen to get up there, but it's usually triggered by something), and once there, it's a begger to get back down again!

What I can't work out (mainly because 2784kbps isn't a natural fault-finding max speed - where a connection may have a maximum sync speed applied for fault resolution), is the exact same sync speed, following multiple reported re-syncs (never seen that before).

What is clear is the margin is unlikely to come down on it's own, when it's being user tweaked, because the error rate may well be above the BT acceptable level (whatever that is - nobody seems to know ).

A quiet line test would be a good idea, but given the line attenuation and target margin (tweaked to about 11dB), his speed isn't too far from where it should be.
But.....Something is causing these dropouts, and it's big (if it's causing a re-sync from 11dB).
My line (about the same length) can cope with virtually anything, when on a 6dB target (even on ADSL2/2+, which can be more prone to noise; but thankfully more stable, which makes up for it).
Im fact, my line is so quiet it copes on a 3dB target (set by BE - without any arguing), except for the odd hour every couple of days (my guess is the neighbour's dishwasher).

Ahaha I think there's a couple of things going on here (well, three if you count me being thick and not checking).

I think I am suffering from sync problems (otherwise my speed wouldn't keep dropping) but I think I'm also suffering from a wireless problem.

Shortly after my last post I lost my conn again - but went downstairs and checked the router. The sync light was still on.

I'm therefore guessing that most of todays drops have been a loss of wireless - which in itself is wierd - and this would explain why when it comes back the sync speed hasn't changed.

Looks like I may have to reconnect my internal extension wiring and move the router back upstairs to better keep track of the "actual" sync losses.

I've never liked the Asus WLAN wireless connection programme thingy. Seems very ropey.

In reply to a post by Discord:

I'm therefore guessing that most of todays drops have been a loss of wireless - which in itself is wierd - and this would explain why when it comes back the sync speed hasn't changed.

Short of a massive coincidence (a dozen re-syncs; all at the same speed), a loss of wireless is the only explanation.

In reply to a post by Discord:

Looks like I may have to reconnect my internal extension wiring and move the router back upstairs to better keep track of the "actual" sync losses.

How much speed do you lose, by reconnecting the extension wiring, and moving the router upstairs?
If it's a fair amount, maybe it's worth investing in some "home-plugs" (do a Google search), which will take a wired ethernet connection, and distribute it around your house, via the mains wiring, and will give you a wired ethernet port [upstairs] to connect your PC.

Also remember; if you put the extension wiring back in place, you'll be adding a long AM antenna into circuit, and will have a bigger chance of re-syncs, and margin changes, than if you leave the router in the master 'test' socket (so you could be creating even more re-syncs, just so you can track them).