Weird results with RouterStats from ADSL2+ line

I am with Be and have been experiencing line drops lately. Not all the time I might add, just in short bursts every few days. I've raised a ticket with Be, and that was not much help, and Ihave discussed on the Be forum, but no clear answers yet. I'm hoping someone here can offer advice. Here's a summary.

I am seeing line drops with the standard Thompson TG585v7 from Be. This only started recently as far as I know. After a few drops, everything usually recovers and keeps going fine for few days. This happens even when we're all out, the PC is off, and no missed telephone calls, so it seems totally random and not inflicted by something at my end

The router is connected directly to the BT test socket.

I have done a quiet line test - it was very quite, and also had BT check for faults when it dropped a couple of days ago, but nothing.

I've now changed to a new router - DG834v4, new filter, new cable.

The sync speed has remained solid all day, and no apparent line drops. This does not necessarily mean the problem has gone away, as mentioned, it's very intermittent.

Anyway, my question here is this. I ran RouterStats and it shows stable connection under noise margin, sync speed etc. However, via the telnet interface, Rx Noise and Rx Sync show random collapse to the floor. Here's a few log entries (see the TelnetRxNoise entry):
18:13:10 Rx-Noise=6.1 Tx-Noise=6.5 Rx-Sync=15237 Tx-Sync=1321 AttnDown=31.5 AttnDown=14.6 TelnetRxNoise=6.3
18:13:45 Rx-Noise=6.4 Tx-Noise=6.5 Rx-Sync=15237 Tx-Sync=1321 AttnDown=31.5 AttnDown=14.6 TelnetRxNoise=0
18:14:41 Rx-Noise=6.3 Tx-Noise=6.5 Rx-Sync=15237 Tx-Sync=1321 AttnDown=31.5 AttnDown=14.6 TelnetRxNoise=6.4
18:15:25 Rx-Noise=6.2 Tx-Noise=6.5 Rx-Sync=15237 Tx-Sync=1321 AttnDown=31.5 AttnDown=14.6 TelnetRxNoise=0
18:15:56 Rx-Noise=6.2 Tx-Noise=6.5 Rx-Sync=15237 Tx-Sync=1321 AttnDown=31.5 AttnDown=14.6 TelnetRxNoise=0
18:16:27 Rx-Noise=6 Tx-Noise=6.4 Rx-Sync=15237 Tx-Sync=1321 AttnDown=31.5 AttnDown=14.6 TelnetRxNoise=6.2

I would show the graphs, but I don't know how to upload!

Any advice on how to debug this issue appreciated.

Routerstats occasionally fails to get a figure, and substitutes 0 instead.
Not much you can really do about it, I'm afraid.
I've seen it, personally, and have helped a few on here with the same issue....
The noise margin isn't collapsing to zero, it's just a false reading, and I think it will be unrelated to your line drops (mainly as it's not a line drop - notice the connection speed remaining at exactly the same level; this hardly ever happens on a re-sync).

I totally agree - the OP is chasing a "red herring".

Thanks guys, that was my suspicion. I'll stop wasting my time on that one then

The good news is that the connection has stayed solid over night. I need to see it run for a good few days before declaring problem solved.

As far as I know, the DG834v4 does not record line resync in it's logs. What is the best way to catch this without dedicating my PC to monitor the router every few seconds?

Yes, just ignore it.

The problem arises because the router tends to ignore telnet requests when it gets busy. The http protocol just keeps trying until it successfully retrieves data but the telnet protocol doesn't have the same 'mechanism' and has to report what it "sees".

In the RouterStats Configuration section, on the Telnet | Experimental Tab, you could try increasing the 'Data Timeout" value to (say) 3000 ms and ensure that the "Retry if timeout" checkbox is checked. Don't overdo it, though, or you could start to miss genuine dropouts.

It's also worth checking that you have the latest ethernet drivers for your motherboard or LAN card.

John.

In reply to a post by aks:

As far as I know, the DG834v4 does not record line resync in it's logs. What is the best way to catch this without dedicating my PC to monitor the router every few seconds?

As adebov said, the line is very unlikely to re-sync at exactly the same speed, so if you see a small sync change, then it will be a re-sync.

In reply to a post by aks:

As far as I know, the DG834v4 does not record line resync in it's logs. What is the best way to catch this without dedicating my PC to monitor the router every few seconds?

Maybe look for the NTP entries in the log.
Normally (if all is working well), you'll only see NTP entries after your IP lease renewal (every 6 or 12 hours if you're on O2 or BE, with dynamic IP), or following a re-sync.

I'm on a static IP with Be. However, I'll monitor the logs for new NTP entries at resync.
Cheers

In reply to a post by aks:

I'm on a static IP with Be.

Even better - You won't have the regular 6 hour IP renewal (and the short loss of connectivity and NTP refresh which go with it).
NTP is not a fool-proof way to find evidence of re-syncs [in the Netgear logs], but it's better than leaving your PC on 24/7 to log routerstats, or sit watching for SNMP messages (one of which may well be sync notification - don't know, haven't tried, but it is with Belkin & Speedtouch routers).