High Resistance Joint Fault Developing?

Hi guys,

I hope you're all well.

I have a feeling that a HRJ fault is developing. This is because I've noticed that my line is starting to become more and more errored and the SNRM is starting to dip crazily at times, especially in the evening. Fortunately, this isn't causing the line to drop out, however I'm slightly concerned, seen as I'm experiencing frequent losses of throughput.

I have attached a screenshot of a recent SNRM plot:

https://i.gyazo.com/9bb65f333d3be0f8d6f81d772edf92af...

I don't want to come over like I'm obsessed again, because honestly I'm not, it's just that this has raised my attention. Should I think about booking an engineer soon?

Thanks!

William

Edited by deleted (Fri 13-Oct-17 13:57:15)

Looks fine to me. Any drop in throughput you are seeing is down to ISP congestion. There's nothing on the DSL side that could be causing that. Errors are extremely low, snrm variance is nothing out of the ordinary.

Should I think about booking an engineer soon?

Absolutely not. If you weren't watching the stats you wouldn't notice a thing.

If you start seeing changes in attenuation or snrm falling and not recovering then an HR fault might be developing. The snrm is meant to go up and down, that's why there's a margin.

I don't think it is due to ISP congestion, I'm reading the drop in throughput of the G.INP Min-EFTR graph, which is frequently dipping below the sync rate. Well, I am noticing it, dropped packets, occasional lag etc. Yeah, the SNRM is falling and not recovering for long periods. I don't see how the SNRM variance is nothing out of the ordinary, especially when it's causing sometimes huge amounts of errors in a short space of time and nearly dropping to 0 dB, that to me does not seem good at all. 0 db = loss of service. Also, the attenuation does change by about 0.5 dB sometimes.

Edited by deleted (Fri 13-Oct-17 16:52:29)

Packet loss from 4 ES?
That's not cause by the DSL circuit.
Why do you ask for advice when you get very defensive when told everything is fine.
It appears to me you're looking for a fault.

The line looks fine to me.

I don't think it is due to ISP congestion, I'm reading the drop in throughput of the G.INP Min-EFTR graph, which is frequently dipping below the sync rate

That's the 1st graph I looked at. Perfectly normal. No idea how you can tell the difference between a couple Mb drop on the MinEFTR graph and ISP congestion. Especially as that occurred for a few mins around 9pm (peak time).

From your stats, there is nothing there that would cause noticeable packet loss or throughput issues. Likely ISP congestion.

Edited by j0hn83 (Fri 13-Oct-17 18:25:54)

Sorry, I'm trying not to be defensive. I'm not sure how that could've be taken defensively, but fair enough...

Yeah, I agree, only 4 DS ES, but one was severe, due to 10's of CRC's in that second. I admit that my line looks "fine", but I tell you, there are many lines that are "better" quality.

The other reason as to why I'm concerned, is because most of the information I've looked at online regarding faults has been linked to very erratic SNRM, which seems to be quite evident on my line, especially recently.

I've just noticed, a good example is very recently, the DS SNRM dropped from 4.3 dB to 2.5 dB within a minute, that to me rings alarm bells.

Another thing to add, when the phone is ringing/in use, the DS SNRM drops and the retransmissions increase dramatically, so surely something must be wrong if that's occurring.

Edited by deleted (Fri 13-Oct-17 18:54:28)

That SNRM plot looks fine could be a bit smoother if it was a ZyXEL modem but generally fine William.

Well, it's not fine, because I've just lost connection for a few minutes, due to a huge noise spike... Tim, sorry but I think that's wrong. ZyXEL routers do not purposely make the SNRM smoother... I think everyone must be looking at the wrong line, my MDWS ID is Grimmybob.

Edited by deleted (Sat 14-Oct-17 21:37:32)

I can only speak as I find William. My TP-Link modem has very spikey SNRM on MWDS but when I swapped over to the ZyXEL VMG1312-B10A the SNRM hardly varies at all and keeps a relatively stable SNRM. But every line is different I guess.

Well, I've just bought this router and it's up there with the best, I'm pretty sure it's an external fault of some kind, like most have been over the years...

That maybe so but over on Kitz, lots of testing has shown ZyXEL devices to be highly regarded with an in-built filter and the best chipset Broadcom make so far.

Sure, but I find the ZyXEL firmwares incredibly buggy, and when I tried to report the issues to their support, they wouldn't help, because they said that I needed to test on several devices which I didn't have...

Most firmware has bugs or needs improvement even Billion. I found ZyXEL support very helpful with a firmware bug and indeed saying they would test it in their lab. I haven't had any problems with the VMG-1312-B10A it just works. What bug did you come across?

Yes, the ZyXEL's work, but it's the way their web pages are scripted and they don't properly format on iOS devices. I also found they use a telnet like implementation for their stats page which I found was full of broken text, etc. But, it wasn't just that, I just prefer Billion as a make, and that's why I'm sticking with them. It has to be something outside of the router, because it works fine most of the time.

I have no problem with telnet on my ZyXEL and am using DSLStats, telnet output on my model and other models has been perfect. My Asus router doesn't display correctly on my Windows Phone but is perfectly fine on PC, not everything is perfect. Having said that the ZyXEL works fine on my Windows phone.

True, but like I said, it wasn't that, that made me choose Billion over it.

What was it then that made you choose the Billion? I have a Billion 7800 for ADSL2+ it is horses for courses. The 7800 was very reliable and I chose it because it had a tweak page so I could adjust the SNR Target as on a TTB line the target was 6db when my line could quite easily handle 3db. I have a Billion 8800NL R2 which syncs at 64mbit @ 6db nice router but the ZyXEL outperforms it by another 7mbit sync higher. The Billion SNRM on MWDS was exactly the same as your Billion, pretty variable, that is just the Billion for you.

Perhaps its time for the poster to report a fault and use more resources to chase down the odd noise spike, or as most people do accept that DSL was designed to resync automatically after noise spikes which are the norm for the RF environment and get on with life.

DSL is cheap and nasty, if resyncs and noise variations cause lose of sleep then time to spend on a full fibre service and only then worry about changes in light level.

Hear, hear.

Tim, sorry but I think that's wrong. ZyXEL routers do not purposely make the SNRM smoother...

I couldn't disagree more.

The ZyXEL VMG8x24-B10A and the ZyXEL VMG1312-B10A both have additional noise filters fitted that I haven't seen on any other device (definitely not on the Billion).
I've seen switching to 1 of these Zyxel devices change an snrm plot dramatically from incredibly spikey to practically a straight line.
They both contain what is regarded as 1 of Broadcoms best performing VDSL2 chipsets, the BCM63168.

You have the (in my opinion) better of the 2 variants, the Billion 8800NL R1 with the favoured BCM63168 chipset. The Billion 8800NL R2 has the cheaper/budget Broadcom chipset the BCM63381.
It's doing its job absolutely fine.

In my opinion all of the above is absolutely irrelevant, and your broadband works fine, so leave it alone.
VDSL is not a perfect system. It's extremely susceptible to external noise, which is why they design it with a noise margin in mind.
It can be tweaked and hardware/cabling optimised to improve stability, but I don't know what you're expecting from tech that uses 2 simple lengths of copper wire.

Twice in the past 24 hours your line has resynced at a lower rate, and it looks like twice a resync has been initiated to get a higher sync again.
Perhaps leave it alone as you will likely find it much more stable running at a few Mb less with a higher snrm.

Edited by j0hn83 (Sun 15-Oct-17 18:04:50)

Not this again! We�ve told you about this in the past. It�s a DSL based technology running over a copper pair. I don�t know what you expect. Stop worrying about the odd drop and get on with your life.