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Continuous Issues With Noisy Line, Multiple Visits Haven't Solved

StopItRawr
Well-informed

Hello all

 

I am on a VM Gig1 (Boosted by Volt!) line and the poor thing appears to be affected by noise that VM can't solve

At the last visit a few months ago the tech replaced all of the internal bits of the line but noted the line to the cab was very old and asked for a re-pull but that hasn't happened yet. However the status page says no known issues and then alternately points to line issues that needs a tech, or sometimes "

Looks like there are issues in your postcode affecting your services"

The logs show multiple T3s and DBC-REQ Mismatch on the logs, as well as "US profile assignment change. US Chan ID: 6; Previous Profile: 12" with the US on the 3.1 side going from QAM128 to as low as 8, there's definitely noise somewhere. Could this be looked into preferably without having to send a poor tech here as they've literally eliminated all possible local issues short of changing the Hub 4 for a 5, thanks!

(DS and US SNRs and Power Levels are in spec)

13 REPLIES 13

jbrennand
Very Insightful Person
Very Insightful Person

Lets see the data - and this will get also you evidence of the issues - which  should help if you wan to leave VM with no exit fees

If you haven’t already, set up a free, secure and “offlsite” - “Broadband Quality Monitor” to continually monitor the state of your connection and record any true network dropouts , latency issues, packet drops, etc - it will thus allow you to differentiate between those and simple wifi dropouts. It does it 24/7/365 and it keeps a visual record of any/all of your network disconnections, useful data to have to match to the Network logs (in your Hub settings) and also in discussions with VM - note it will take a few hours to start seeing a sensible picture - post up the “link” to the “share live graph”. Click the lower link (Share Live Graph) then, click generate. Copy the text in the Direct Link box, beware, there may be more text than you can see. On here click the Link icon (2 links chain to the left of the camera icon) In the URL box paste the link you copied and then click OK

https://www.thinkbroadband.com/broadband/monitoring/quality


--------------------
John
--------------------

I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired, 2 on WiFi) Hub5 in modem mode with Apple Airport Extreme Router +2 Airport Express's & TP-Link Archer C64 WAP. On Volt 350Mbps, Talk Anytime Phone, x2 Mobile SIM only iPhones.

If only I could, my bloody router setup, The Hub 4 is in modem mode and I use a Huawei AX3 Pro in tandem with an Honor Router 3 in Link+ Mesh mode blocks the BQM even with every firewall related thing turned off, any suggestions to get the thing responding would be lovely.

Anyway, stats look *fine* normally but when noise issues occur, US goes to 52+ dBmV on the 3.0 channels and as you'll see, US 3.1 is now on QAM32 with Uncorrected RS errors on the DS 3.1 implying that side of things is unstable.

3.0 Downstream channels



3.0 Downstream channels

Channel Lock Status RxMER (dB) Pre RS Errors Post RS Errors

25Locked40.36628700
1Locked40.36628700
2Locked40.36628700
3Locked40.36628700
4Locked40.94620900
5Locked40.94620900
6Locked40.36628700
7Locked40.94620900
8Locked40.36628700
9Locked40.94620900
10Locked40.36628700
11Locked40.36628700
12Locked40.36628700
13Locked40.36628700
14Locked40.36628700
15Locked40.36628700
16Locked40.36628700
17Locked40.36628700
18Locked40.36628700
19Locked40.36628700
20Locked40.36628700
21Locked40.36628700
22Locked40.94620900
23Locked40.36628700
24Locked40.36628700
26Locked40.94620900
27Locked40.94620900
28Locked40.94620900
29Locked40.36628700
30Locked40.94620900
31Locked40.36628700



3.1 Downstream channels

Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)
159964K1840QAM4096424


3.1 Downstream channels

Channel ID Lock Status RxMER Data (dB) PLC Power (dBmV) Correcteds (Active Profile) Uncorrectables (Active Profile)
159Locked435.7579756236227

 

3.0 Upstream channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
13010000039.5205995120 KSym/sec64QAM4
22360000039.0205995120 KSym/sec64QAM5
33660000040.0205995120 KSym/sec64QAM3
44310000040.5205995120 KSym/sec64QAM2
54960000040.5205995120 KSym/sec64QAM1



3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
1US_TYPE_ATDMA0000
2US_TYPE_ATDMA0000
3US_TYPE_ATDMA0000
4US_TYPE_ATDMA0000
5US_TYPE_ATDMA0000



3.1 Upstream channels

Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation
610.031.02KQAM32


3.1 Upstream channels

Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts
6OFDMA20053.900

 

I think you'll agree something isn't looking right and internal signal issues has been eliminated by multiple engineer visits.

Hi StopItRawr 👋 Sorry to hear about these issues with your service. 

Sadly we are a little limited with what testing and support we can run whilst your hub is in Modem mode. Having had a look there do not appear to be issues at the exchange which would be affecting your service. 

Are you also able to give us a little more information about the effects you are seeing on your service? (For example speed issues, or an intermittent connection?)

Did the last technician advise you would benefit from a new hub? Just as you have mentioned they have previously attended and ruled out and issues with internal wiring. 

If you would be happy to pop your hub in Router mode for a couple of days this will help us gather data to identify where the issue is! (This also just rules out there being any issues with your 3rd party networking equipment.)

If the issue is due to SNR in the area the field and networks team will be aware of the issue and working to get it resolved as quickly as possible. SNR (signal to noise ratio) is just a technical term for interference of the Broadband signal caused by noise which ingresses on to our network. It's a difficult problem to locate and diagnose because noise can ingress anywhere on the network. As a general rule it's normally caused by customer equipment e.g. loose connections or 3rd party equipment attached to our network. However it can also be attributable to local architecture, e.g street cabinets, cabling or at the origin of the signal which we call the Headend (servers/routing system). 
The only way to establish where the noise is originating is for the Network Techs to run a series of trace routes. Once found then the cause dictates the amount of work required and the time frame for resolution. 
Hope this helps! Please let us know about the extra questions requested so we can continue to offer support! Thank you for your patience in the meantime. 🌞

Molly

Hello sorry for the late reply, my youngest had their birthday last week.

I very much doubt that being in Modem mode will cause T3 errors, the US going to 50+ dBmV and the following network log:

Network Log

Time Priority Description

Tue Jun
6US profile assignment change. US Chan ID: 6; Previous Profile: 12; New Profile: .;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Tue Jun
5DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Tue Jun
6US profile assignment change. US Chan ID: 6; Previous Profile: 12; New Profile: 11.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Tue Jun
5DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Tue Jun
6CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 1.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Tue Jun
6US profile assignment change. US Chan ID: 6; Previous Profile: ; New Profile: 12.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Tue Jun
6CM-STATUS message sent. Event Type Code: 23; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Mon Jun
6US profile assignment change. US Chan ID: 6; Previous Profile: 11; New Profile: 12.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
Mon Jun
5DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;

 

StopItRawr
Well-informed

I have a Hub 4 and wasn't offered any replacements of any sort to try to help despite multiple visits. Again, the last engineer said they ordered a re-pull because of external damage to the line (They used a line from a non served house in the locality). The DOCSIS 3.1 DS has post RS errors constantly, a sign of noise, and the US keeps dropping and changing frequency.

3.1 Downstream channels

Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)

159964K1840QAM4096424



3.1 Downstream channels

Channel ID Lock Status RxMER Data (dB) PLC Power (dBmV) Correcteds (Active Profile) Uncorrectables (Active Profile)

159Locked435.516118591921204

StopItRawr
Well-informed

Event code 24 is specifically for line noise, so it's a factor.

StopItRawr
Well-informed

US down to QAM8 again

 

3.1 Upstream channels

Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation

610.044.02KQAM8



3.1 Upstream channels

Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts

6OFDMA20053.920

Thanks for coming back to us StopItRawr, our system is showing that there are issues with your upstream channels that would need a technician visit to resolve. As you have had numerous visits already, are you okay for me to arrange another visit for you?

Kind Regards,

Steven_L

If you can mark that all internal wiring has been replaced already and the only thing left to change internally is the Hub 4, yes please. I do feel the issue is external however!