Line Issues (was: Probably Not Router Problem)?

[#1]

I've posted about this before, but I was moved onto ADSL2+ a few months ago and, in the last three weeks or so, I've been having a problem whenever my connection resets to a download connection speed over about 6MB (I was on a steady 3.5MB before the move with no problems).
After a period of time, response becomes more and more sluggish (browsing, e-mail, even doing tracert) until it simply won't do anything (tracerts done at that time show an awful lot of '*'s - when it can find the next node, that is). The noise margin bounces up and down like a ninny between 0-3 db, occasionally going to some ridiculously large number over 2 trillion db (I understand that this is a knownreporting bug in this model when noise margin goes negative).
I've ruled out: the telephone cabling between the master socket and the extension (tried connecting straight into the master socket); the NIC card on this PC (another PC connected straight into the router has the same issues); the microfilters (changed them).
The router is a Netgear DG834v3 (wired), getting on for four years old. Could it be on its way out, and that it can't handle the higher speeds? Or is that model a problem at higher speeds anyway?
If the problem continues, I'm going to try to roll back the firmware to the previous one, and even reset to factory settings, but I'd be grateful for your opinions.

[#2]

Quote from: thejudge

The router is a Netgear DG834v3 (wired)

Not known to be good with ADSL2+ due to a chipset incompatibility between the router and the MSANs at the exchange. The V4 is very good, though. I passed mine on to a friend who was getting less than 2Mb with a SpeedTouch USB modem. Once I sorted his hilarious wiring problems, we got the connection up to over 6Mb with my old DG834v4, since when over the last few months he now gets over 14Mb.

[#3]

This Kitz forum thread might be of interest. 3 years old but the firmware versions mentioned in the opening and closing posts seem to be the latest.

[#4]

I've just installed an old Thomson Speedtouch ADSL modem to test. It has synched at the same rate as the router (6.3MB). At first, it seemed to be having the same problems as the Netgear, but that seemed to clear up after a few minutes.
I'll keep it this way and monitor for a while (particularly during the evenings, which is when the problem with the router seemed to be at its worst - increased noise/contention, I suppose). If all goes OK with this, I'll go and buy a DG834v4 (I need a router to network the other machine with this one).
Thanks for advice so far.

[#5]

Quote from: Jaggies

Quote from: thejudge The router is a Netgear DG834v3 (wired) Not known to be good with ADSL2+ due to a chipset incompatibility

I think you'll find that applies to the Bethere (and O2 LLU) services ONLY.
Even then it's only a minor speed restriction on shorter (faster) lines.
My neighbour happily runs that exact model on a Be connection at well over 15mbps. 

[#6]

Now this is giving cause for concern.
I went away from the PC for an hour or so (leaving the modem on and connected). When I came back, I found that it had disconnected in the meantime and reconnected at a lower speed (about 5.2MB). I started to do some work online. Whilst doing so, it disconnected.
I tried reconnecting, and it said that there was no dial tone. It took three attempts to get the connection back.
It has now done the same thing three times in about 15 minutes.
I'll try with the router again in a minute, but does this look more like a line fault now?
PS. When trying to post this, it disconnected me again. When I tried to reconnect this time it said:
"The PPP link control protocol was terminated".

[#7]

Further update:
I reconnected the Netgear router. All seemed to be OK for about 40 minutes, then it started playing up again.
The stats looked like the attached image.
I did a tracert:
C:\Documents and Settings\User>tracert www.guardian.co.uk
Tracing route to www.guardian.co.uk [77.91.248.30]
over a maximum of 30 hops:
  1    <1 ms    4 ms    4 ms  192.168.0.1
  2    43 ms    42 ms    38 ms  lo0-central2.ptn-ag01.plus.net [195.166.128.203]
  3    34 ms    32 ms    28 ms  gi2-11-121.ptn-gw01.plus.net [84.92.3.145]
  4    33 ms    33 ms    32 ms  po4.ptn-gw02.plus.net [212.159.1.139]
  5    33 ms    31 ms    55 ms  ge-0-2-0-0.lonth-inter-2.interoute.net [195.66.2
26.53]
  6    34 ms    33 ms    34 ms  195.81.242.238
  7    33 ms    33 ms    33 ms  77.91.255.137
  8    33 ms    33 ms    35 ms  77.91.255.198
  9    *        *        *    Request timed out.
10    *        *        *    Request timed out.
11    *        *        *    Request timed out.
12    *        *        *    Request timed out.
13    *        *        *    Request timed out.
14    *        *        *    Request timed out.
15    *        *        *    Request timed out.
16    *        *        *    Request timed out.
17    *        *        *    Request timed out.
18    *        *        *    Request timed out.
19    *        *        *    Request timed out.
20    *        *        *    Request timed out.
21    *        *        *    Request timed out.
22    *        *        *    Request timed out.
23    *        *        *    Request timed out.
24    *        *        *    Request timed out.
25    *        *        *    Request timed out.
26    *        *        *    Request timed out.
27    *        *        *    Request timed out.
28    *        *        *    Request timed out.
29    *        *        *    Request timed out.
30    *        *        *    Request timed out.
Trace complete.
I've now connected straight into the master socket (I think it's one of those without a test socket), and will see how long it lasts this time.

[#8]

Have you unplugged everything from all the other telephone sockets?

[#9]

Hi Jelv.
Yes, I took both telephones out of the system.
Once again, the thing seemed OK for a little while (connected straight into the master socket), then it went again.
I flushed the DNS cache just in case, then connected the router straight into the socket (bypassing the surge protector). Same thing happened after a short while. Browsing impossible, and tracerts like this:
C:\Documents and Settings\User>tracert www.plus.com
Unable to resolve target system name www.plus.com.
C:\Documents and Settings\User>tracert www.plus.com
Tracing route to portal.plus.net [212.159.9.2]
over a maximum of 30 hops:
  1    6 ms    6 ms    6 ms  192.168.0.1
  2    *      37 ms    *    lo0-central1.pcl-ag03.plus.net [195.166.128.238]
  3    34 ms    *        *    gi1-6-311.pcl-gw01.plus.net [84.92.6.64]
  4    *      41 ms    *    gi5-8.ptp-cr01.plus.net [84.93.224.48]
  5    41 ms    43 ms    41 ms  vlan2657.ptp-elb01.plus.net [84.93.224.36]
  6    43 ms    *      41 ms  portal.plus.net [212.159.9.2]
Trace complete.
I took the covers off both the master socket and the little white box in the pantry where the line comes into the house and brushed some dust/fluff out, but no change.
I've now connected the router without microfilter (as no phones are connected at the moment) and am trying again, but I'm not optimistic.
As all that I've done seems to rule out:
1) the router
2) the NIC card on this PC
3) the extension wire
4) the microfilter(s)
5) the telephone(s)
6) the phase of the Moon
I'm left with the feeling that the problem is with the line. Would +Net be able to do any checks from their side?

[#10]

PS to the above:
When I tried to send my last post, it disconnected again, and it took a good few goes to reconnect.
I've noticed that when the connection breaks (or is broken by me trying something else), it takes a long time for negotiation/authentication (30-40 seconds or more).

[#11]

Here's the latest:
I put everything back exactly as it was before I started diagnostics. The connection has held for 1.5 hours now, but look at this speed on a 6MB connection:

Streaming anything is now out of the question, and pages with graphics are taking an age to load.
Anyone any idea what might be happening here?

[#12]

This is a bit odd.
I've been online since about 13:00 today. The router had resynched shortly beforehand and had come back at 6.7MB, which is the sort of level which has been giving me problems for weeks.
The connection has now been solid as a rock for over 5 hours with a download speed of a steady 4.5MB.
I'll monitor it through the evening.

[#13]

Right.
Something happened between 19:00 and 20:00.
All was OK at 19:10: Synch speed still 6.7MB, download speed 4.5MB.
At 20:10, my synch speed was still 6.7MB, but my download speed had crashed to 514kB. The noise margin had gone cuckoo again and I couldn't browse. Connection status in the router was showing 'Disconnected', the 'Negotiation' field was showing 'LCP down', then 'LCP is allowed to come up', but it didn't seem to be able to authenticate.
I've now had to reboot the router to get anywhere. It has synched at 5.7MB, I can browse again and the Thinkbroadband speedtester is showing 4.7MB.
Has anyone any pointers as to what I can do next? I'm at my wit's end, and that's not a long journey these days.

[#14]

OK, here's the latest:
After I rebooted the router and reconnected eighteen hours ago, everything has been rock-solid stable since (synch speed 5.7MB, download speed 4.7MB, no resynchs overnight).
I'll monitor again throughout today and see if the same issue occurs this evening.

[#15]

Hi there, it's looking good - your latest connection has been on for over 36 hours now so hope things stay that way for you Let us know if not or if there's anything else we can do.