Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: DaveG6HNI on November 03, 2022, 09:03:05 PM
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Hi, I'm new hear, so apologies if I'm not explaining my issues properly.
I have had FTTC for about 12 years, PN 40/10. For most of the first 9 years I had a relatively steady 35Mbps. I then purchased a Fritzbox 7590 router and for the next 9 months my DL speed increased to 37Mbps, DSLAM was 40Mbps, syncing at 39.99Mbps, Max obtainable 44Mbps and SNR 7dB.
Then over the next few weeks DSLAM reduced in steps down to 28.4Mbps. Plusnet requested an Openreach engineer who checked the line but could not find a fault. DSLAM was reset back to 40 Mbps, but slowly dropped down again over the next 2 months. This process has been repeated every few months for the last 2 years ! BT have lift & shifted me to different ports, but the same thing happens and some ports have had other issues. I am currently on what appears to be a good port according to my stats, but it is still dropping every few weeks :(
I signed up for a whitebox with SamKnows a while ago and that tells me my packet loss currently is 0.058% although I think it used to be even lower. My Fritzbox stats usually show very few CRC errors or error seconds, but once every couple of weeks they increase significantly for a few hours before returning to a low level, but this I believe causes DLM to reduce my DSLAM shortly after and before DLM decides to increase DSLAM it happens again, hence the slow reduction in speed.
If I could get DLM disabled, then my line would function perfectly for 99% of the time. When the errors do increase, I can't at the time even notice the issue, but DLM means my speed just gets slower and slower until I am forced to get Plusnet to reset it.
Any help or suggestions welcome
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Hi, I'm new hear, so apologies if I'm not explaining my issues properly.
Welcome to the kitz forum. :)
If I could get DLM disabled,
That is not possible. The DLM is mandatory process for all (FTTC / VDSL2) provisioned circuits.
Please take a look at Section 2.2.1 of the Openreach SIN 498 (https://www.openreach.co.uk/cpportal/content/dam/cpportal/public/images-and-documents/home/help-and-support/sins/documents/SIN_498.pdf).
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Can you post your line stats please as reported by your modem.
sync speed, SNR margin, error rate (if possible).
You not necessarily banded but could be either crosstalk or other stability profiles such as interleaving.
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As already asked, if you could give us some numbers that may assist. If the large amounts of errors only occur every few weeks then that suggests some form of electrical interference is causing it and that may be hard to track down.
This sounds like a situation where DSLstats could help in identifying the extent of the errors and exactly when they are are occurring but you may need to change routers to use it as I'm not sure it's compatible with the Fritz one you currently have.
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Thanks for the reply, I thought I did include the router's info, but here are some screenshots from my router and from SamKnows, I did have a 1 second power cut last night which reset my router, plus a link to my Thinkbroadband graph...
https://www.thinkbroadband.com/broadband/monitoring/quality/share/9924157ce3456d4c1011c66b7290a6c3818a65bf-04-11-2022
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I can only attach 3 images so here are the second 3
I have two years' worth of these screenshots if you want to see more.
I too thought it was external as I have not been able to link an appliance, boiler, oven, etc to the issues.
I have no internal wiring and the recently replaced feed from the pole connects directly into a new master socket.
I am 800 m from my cabinet, which one BT Eng said was the issue, but as mentioned for 10 years I had no issues except for 2 line faults that were quickly corrected. It is only the last 2 yrs that my max DSLAM keeps reducing in steps until I get PN to reset it.
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Do you know the reasons for those disconnections logged by samknows?
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HI, the last two were the power cut, one the coincides with the speed drop was DLM reducing my max DSLAM from 40 to 35, the one last Friday was I think when DSLAM was reset to 40, but no idea what caused the one on Monday...
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Is there no FTTP in your location ?.
Dave G6HNI Are you a Radio Ham ?.
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I think that’s a fair conclusion. If you remove one “s” from my user name you get a similar result :P
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I wonder what all the traffic is that is showing on the TTB graph? It seems constant 24 hours a day.
If you turn off your connected devices until you work it out, then start your tests again.
First thing I would try is the Samknows box, had it years ago, but found it generated 3 or 4 times more traffic than the rest of my devices put together.
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Hi everyone 3 or 4 questions to answer here...
1. No FTTP or I would have already upgraded :)
2. Yes I am a Radio Ham
3. I too wonder about the apparent constant traffic, but it does not seem to rack up any data usage ?
I have a few CCTV cameras, plus the SK Whitebox, plus ThinkBB all on 24/7 and have always put it down to them...
Interestingly yesterday's TBB trace shows some low level interference up until about 1am when it stopped, checking my SK stats, some packet loss at around midnight ?
https://www.thinkbroadband.com/broadband/monitoring/quality/share/7412e2470be7328dcbfdbea2f0bf274aaa7dd933-06-11-2022
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What’s different between 0000 and 0400 where the traffic is much reduced. Also noteworthy is the low latency confirmation interleave is not on the line.
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I do not know why sometimes it all goes quiet, although it often happens just after a resync... ?
AFAIK No interleaving, but can't see where to find it in router settings.
I've always had low latency ?
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You can’t set interleave it’s done automatically if the DLM thinks you need it, but that’s unlikely in your case with g.INP.
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DLM has caused another Max DSLAM drop over night...
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4th image
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Have you tried using a different modem instead of the Fritzbox?
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You had over 9,000 ES on Monday. I'm not surprised DLM took action.
I'm surprised your internet was usable on Monday I expect the packet loss would have been bad.
The sites owner kitz gets similar error bursts. She uses a Broadcom chipset modem with dslstats set to alert her if the errors start to climb.
She then resyncs her line which stops the errors, preventing DLM action.
Have you tried resyncing during the high errors to see if they stop?
If be tempted to try another modem to see if it keeps happening.
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I'm not sure if my Fritz 7950 allows me to receive error alerts I will investigate that, thanks.
I purchased a second 7950 about 6 months ago and have switching them over to see if that made a difference, but it didn't.
I had no issues for the first 8 months of using the 7950, so I don't think that can be the issue ?
Previously I was using the original BT supplied modem and an Apple Airport Extreme, but I could not see the stats at all with that setup.
I did try using the BT modem & 7950 in Bridge Mode, but again I could not see the stats
I also tried a cheap TP Link modem with the 7950 which worked but still seemed to suffer from these error bursts as you call them, do you have any idea what caused them ?
I try to check my ThinkBB graph daily and if I see errors I do try a resync, but it is usually too late to stop DLM kicking in, below is what I saw on Saturday when I last did a manual resync...
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I would get a HG612 off eBay ( unlocked) max £15. The use DSL stats to monitor the connection 24/7 it should give you a lot of info.
http://dslstats.me.uk/. Free, the developer is a mod on here and helped numerous connections
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The HG612 looks like the original modem BT supplied ?
If so I have 2 or 3 of those, but I don't think any are unlocked ?
I guess the unlocked ones use different firmware ?
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Fritzbox if I remember right is known to restrict pings which can lead to packet loss been shown on TBB on a healthy connection, is it possible to use a different router temporarily?
If not I think there is an option to set pings to no rate limiting somewhere in the interface.
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Yes they do, big there are instructions here on how to do it. I can’t just locate it but others can point you in the right direction. Then you will have much more comprehensive information than what you have. If you look at the dDSL stats web page you can see the myriad of reports.
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My Fritzbox is also my MESH, DECT and VOIP base plus my smart thermostat controller, so I would be lost without it.
Also as previously mentioned everything worked fine for at least 8 months.
I would like to try setting pings to no rate limiting if I could find it, I did find "Filters" and stealth mode is enabled, but not sure if that is what you are referring to ?
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Firewall in stealth mode
In stealth mode the FRITZ!Box firewall rejects unsolicited queries from the internet instead of replying with ICMP control messages. It continues to reply to queries frequently required by programs. Enable this option if you want to make it more difficult to identify your FRITZ!Box through port scans.
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. . . there are instructions here on how to do it. I can’t just locate it but others can point you in the right direction.
Please see the HG612 FTTC Modem & Line Stats (https://kitz.co.uk/routers/hg612unlock.htm) page.
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Yep try disabling that stealth mode, more info here.
https://forum.kitz.co.uk/index.php?topic=26098.0
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Please see the HG612 FTTC Modem & Line Stats (https://kitz.co.uk/routers/hg612unlock.htm) page.
Thanks I will have a read
Also I have disabled Stealth Mode in Filters to see if it works...
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Now that I have disabled Stealth Mode how can I check to see if it has made a difference ?
One of the links mentioned something called "F8Lure" ?
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Give it at least 15 minutes or so and see if the TBB graph looks any better.
Might need to refresh the TBB page with dev tools open in browser (and disable cache ticked) as it has aggressive caching.
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I can't see a difference as of yet, but there were very few losses today anyhow, best I monitor it for a day or two...
https://www.thinkbroadband.com/broadband/monitoring/quality/share/a9f8c2d515d025d3353be201a6d6b1313ba8132d-09-11-2022
I found this on AVM site which confirms I should disable Stealth Mode
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If the FRITZ!Box should reject unsolicited requests from the internet instead of replying with ICMP control messages, enable the option "Firewall in stealth mode" under "Internet > Filters > Lists > Global Filter Settings" in the FRITZ!Box user interface.
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So what about the other currently enabled filters, NetBIOS packets, Teredo packets and WPAD packets ?
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You can leave those alone unless you actually need Teredo (xbox use).
Firewall should be by default in deny all mode on the WAN anyway except ICMP (with holes pocked through for NAT port forwarding), so these are only extra filters on top of those rules.
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You can leave those alone unless you actually need Teredo (xbox use).
Firewall should be by default in deny all mode on the WAN anyway except ICMP (with holes pocked through for NAT port forwarding), so these are only extra filters on top of those rules.
OK thanks, I can still see the odd little red spike on TBB graph, but Fritz box stats look fine at present, so let's hope they stay that way, then I can ask PN to reset DLM/DSLAM back to max (40Mbps)
I will dig out my BT modem in the meantime just in case...
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Ok, this problem wont have caused you to get DLM affecting your line, the suggestion was just to make sure TBB was more accurate in giving an idea of packet loss levels.
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Interestingly DLM/MAX DSLAM has recovered slightly this AM, back to 35Mbps so now I'm thinking that disabling Stealth Mode may have affected DLM somehow ? as I have never seen it recover, it has always just dropped ?
TBB graph remains pretty good and Fritzbox reports no uncorrected DTU and just a few corrected DTU (21 per min) not sure how good or bad that is ?
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Interestingly DLM/MAX DSLAM has recovered slightly this AM, back to 35Mbps so now I'm thinking that disabling Stealth Mode may have affected DLM somehow ? ...
It can't possibly make any difference as Stealth Mode is a firewall function (ie TCP level) that DLM neither knows nor cares about.
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Interestingly DLM/MAX DSLAM has recovered slightly this AM, back to 35Mbps so now I'm thinking that disabling Stealth Mode may have affected DLM somehow ? as I have never seen it recover, it has always just dropped ?
The DLM only monitors the xDSL link. It can't see anything internet related like tcp/udp/pings etc.
It's the Error seconds (ES) that shot up that caused the DLM to lower the banding level used, reported as MAX DSLAM on the Fritzbox.
The DLM increasing this limit would be because it has seen the line performing better, which will be in the form of low Error Seconds, or something similar.
What you do with your internet connection doesn't effect the xDSL circuit. The xDSL is just the link between you and the cabinet and your data runs transparently over this.
You get the same ES not using your connection as you do downloading/uploading at full rate.
Your issue is the DLM is seeing ES which can only be down to the modem, the DSLAM or the copper pair running between the 2.
ES can be caused by all manner of things from failing modems, bad joints in the copper, a dodgy DSLAM port or electrical interference from faulty equipment in your home or anywhere in close proximity to your line between you and the cabinet.
Water pumps/sewage pumps/high wattage machinery/even faulty electric fences anywhere between you and the cabinet can cause ES on a line.
The only thing you are in control of that can improve things is your modem and your internal wiring (extension wiring) at the master socket.
That's why trying another modem was suggested.
If your Fritzbox was failing/developing a fault then substituting it for the other Fritzbox would help.
I'd recommend unlocking your HG612 and running dslstats as it gives excellent graphs of everything xdsl related.
The HG612 also has a different vendor chipset in it which might play nicer with your DSLAM.
Your DSLAM is a Huawei made DSLAM with a Broadcom chipset inside. The HG612 also has a Broadcom chipset.
Dslstats can run on Windows, Linux or a raspberry pi.
This would likely be tricky for Openreach to identify due to the intermittent nature of it.
Ideally you catch this during the burst of errors and if it's caused by electrical interference, tracking down the source.
I mentioned further up the thread that kitz had something somewhat similar. ES would start out of nowhere, cause unknown, and would continue until the DLM resynced her line.
However a simple resync by kitz stopped the ES immediately, until the next episode days or weeks later.
Try resyncing your modem if you catch the error bursts happening to see if they stop.
Dslstats has the ability to alert you via email when an ES burst happens.
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This would likely be tricky for Openreach to identify due to the intermittent nature of it.
Ideally you catch this during the burst of errors and if it's caused by electrical interference, tracking down the source.
OR's NATO diagnostic tool, is fantastic for scrutinising this kind of potential interference fault.
One can filter down to the serving DP and compare all circuits against each other, to drill down to how many circuits are experiencing the same issue, with the same timings.
Thing is, there's a lot more protocols to satisfy before it gets to that stage, as you say, the internal wiring/router/copper pair could well be knackered.
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So what constitutes good or bad error seconds ?
Looking at my router it says I have had 42 seconds with errors since it resynced 18 hours ago ?
With ref to other recent suggestions, I have no internal wiring, the Master Skt and feed back to the telephone pole were replaced about a year ago, I have been "Lifted & Shifted" to a new port several times each new port being worse than the last. I am on my 2nd Fritzbox 7590 which is on a filtered UPS and most times the interference/Errors occurs at night when nothing of mine is switched on other than my Fridge/Freezer which I can't easily switch off.
I have found my BT HG612 so will look at your suggestions involving trying that and report back.
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I agree with the modem swap to help you figure out whats going on.
42 errored seconds in 18 hours is pretty good.
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42 ES in 18hrs is pretty much a perfect circuit.
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Mine's a bit better than that :)
# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 32383 Kbps, Downstream rate = 80680 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 2.0 9.1
Attn(dB): 15.6 0.0
Pwr(dBm): 13.0 6.6
Since Link time = 29 days 12 hours 51 min 35 sec
FEC: 73674111 0
CRC: 0 1781
ES: 0 1477
SES: 0 5
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Don't get any ES here! The short link time is only caused by power outages.
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here is mine
xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 27306 Kbps, Downstream rate = 86871 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.9 10.5
Attn(dB): 12.2 0.0
Pwr(dBm): 12.5 -0.2
Total time = 111 days 3 hours 33 min 18 sec
FEC: 14844 0
CRC: 0 5494
ES: 0 4754
SES: 0 1
UAS: 43 43
LOS: 0 0
LOF: 0 0
LOM: 0 0
Retr: 0
HostInitRetr: 0
FastRetr: 0
FailedRetr: 0
FailedFastRetr: 0
Since Link time = 111 days 3 hours 33 min 18 sec
FEC: 14844 0
CRC: 0 5494
ES: 0 4754
SES: 0 1
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Retr: 0
HostInitRetr: 0
FastRetr: 0
FailedRetr: 0
FailedFastRetr: 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
ZySH>
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Mine's a bit better than that :)
...
Is the cabinet in your sitting room? ::) ;D
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@tubaman No, it is approx 450 to 500 metres away, I only get full 80 Mbps sync after a power cut when my HG612 syncs up quicker than other modems on the cabinet, that's why the SNRM is low but it doesn't seem to cause any problem with errors. ;D
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here is mine
xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 27306 Kbps, Downstream rate = 86871 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.9 10.5
Attn(dB): 12.2 0.0
Pwr(dBm): 12.5 -0.2
Total time = 111 days 3 hours 33 min 18 sec
FEC: 14844 0
CRC: 0 5494
ES: 0 4754
SES: 0 1
UAS: 43 43
LOS: 0 0
LOF: 0 0
LOM: 0 0
Retr: 0
HostInitRetr: 0
FastRetr: 0
FailedRetr: 0
FailedFastRetr: 0
Since Link time = 111 days 3 hours 33 min 18 sec
FEC: 14844 0
CRC: 0 5494
ES: 0 4754
SES: 0 1
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Retr: 0
HostInitRetr: 0
FastRetr: 0
FailedRetr: 0
FailedFastRetr: 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
ZySH>
Wish I keep my mouth SHUT! Cos it now banded on the line :-\