Significant latency and connection problems

[mrobinson97]

Hi all, for the past month at least I have been experiencing lag spikes.

It's most noticeable during video calls for work where I will be disconnected for 20 - 30 seconds and in online gaming, where the ping spikes and I get booted from the game. There's no faults in my area according to the app.

This happens on all wired and wireless devices seemingly. 

I have been trying to troubleshoot this for a week or so and have discovered the BQM tool;

Now I'm no expert, but this cannot be a normal quality of service. I have been on with VM tech support but I don't think resetting my Hub another time is going to help with this.

Any advise is greatly appreciated! 

[Sephiroth]

Your upstream/downstream stats and Network Log from the Hub's user interface would be helpful in helping to diagnose the problem.  The BQM is unusual (compared with others) in that the greatesy latency appears on the downstream (the yellow bit) yet the packet loss often means an upstream problem.  If both are suffering, it may be nothing more than a loose coax cable.

Also do please provide a postcode and if you have an opportunity to check with neighbours, are they experiencing problems?

[mrobinson97]

Thanks for the reply Seph!

Checking all connections on my end looks ok. Will still triple check this though.

My Postcode is BT191AN.

And the Network log is basically these warning & critical entries repeated indefinitely:

Time Priority Description

02/09/2024 08:58:18	notice	LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
02/09/2024 08:53:7	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
02/09/2024 08:53:3	critical	SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
02/09/2024 08:33:41	Warning!	RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

[Sephiroth]

If you can also provided the upstream & downstream power levels for completeness.  The postcode was requested so that it might be tied in with what others might report.  In this case, not yet.

The Network Log would have more in it, imo, if there were to be any dodgy power/noise levels.  But we'll see when you post the stats.  If upstream & downstream are showing issues in the BQM, then it may be no more than a coax cable coming loose - either in your house or in the feed box on the outside of your property.

Also the neighbours:  similar problems?  Important to know this because it then raises the stakes with VM.

[mrobinson97]

Below are the Upstream & Downstream stats:

Neighbours with VM that I've been able to contact haven't noticed any significant issues with their service. 

[Sephiroth]

Thanks.  There's a clue in the stats.  The downstream power& SNR are in spec but low.  The upstream power is fine (albeit low - but that power level is commanded from the VM end).  I suspect the following:

1.  Your house is situated near to the street cabinet serving your broadband;

2.  There is an attenuator attached to the rear of your Hub 3.  This might now be a noise source.

If you do have an attenuator, please remove it and tighten everything up again.  Then post your stats again.  I would like to see the downstream SNR rise to around 39/40 and the power level rising to present + whatever the attenuator says as a number.

PLEASE NOTE:  There is a 2nd page of downstream stats showing the number of uncorrected errors (as in lost packets).  We should see the before/after data.

Keep us posted.  If this solves it, no need for the round-the-houses you might suffer if the VM bods say everything is in spec!

[mrobinson97]

So the 2nd page of Downstream stats for completeness:

Channel	Locked Status	RxMER	Pre RS Errors	Post RS Errors
1	Locked	38.9	59126	33716
2	Locked	38.6	75741	3052
3	Locked	37.6	79326	5926
4	Locked	37.3	62771	25073
5	Locked	38.9	45242	44232
6	Locked	38.6	36311	43336
7	Locked	38.6	35209	41708
8	Locked	38.6	35035	35930
9	Locked	38.6	35773	46264
10	Locked	38.6	30310	55778
11	Locked	38.6	5949	79593
12	Locked	38.9	11109	78335
13	Locked	38.6	38587	48478
14	Locked	38.9	47651	31861
15	Locked	38.6	45570	10865
16	Locked	38.6	40858	10717
17	Locked	38.6	6461	9031
18	Locked	38.6	1540	14273
19	Locked	38.6	1599	10960
20	Locked	38.6	1656	11062
21	Locked	38.6	1765	11680
22	Locked	38.6	2939	10697
23	Locked	38.9	2635	11095

There is a device on the rear of the hub, although it's a Wideband Equaliser rather than attenuator. A quick google tells me that the two effectively have opposite functions, so I'm hesitant to remove it for now. 

Happy to remove it and see what happens, if you also think a Equaliser could be a source of noise opposed to an attenuator? 

Edited: Replaced Image of downstream stats with table 

[Sephiroth]

You can safely remove the equaliser.  It's a passive device but it could break down internally.  The worst that can happen when you connect it all back up is that your power levels go out of spec - that will affect performance and damage nothing.

Your stats haven't been approved by the mods so I can't see them.  Are there any uncorrectable errors?

[Sephiroth]

I can see them now.  It's exactly as I suspected.  The downstream is in serious trouble.  Those numbers are lost packets.  I hope that removing the equaliser removes the problem.  If not, we'll talk about that.

[mrobinson97]

Will give it a try and report back shortly!

Apologies! I'll add it as a table instead:

Channel	Locked Status	RxMER	Pre RS Errors	Post RS Errors
1	Locked	38.9	59126	33716
2	Locked	38.6	75741	3052
3	Locked	37.6	79326	5926
4	Locked	37.3	62771	25073
5	Locked	38.9	45242	44232
6	Locked	38.6	36311	43336
7	Locked	38.6	35209	41708
8	Locked	38.6	35035	35930
9	Locked	38.6	35773	46264
10	Locked	38.6	30310	55778
11	Locked	38.6	5949	79593
12	Locked	38.9	11109	78335
13	Locked	38.6	38587	48478
14	Locked	38.9	47651	31861
15	Locked	38.6	45570	10865
16	Locked	38.6	40858	10717
17	Locked	38.6	6461	9031
18	Locked	38.6	1540	14273
19	Locked	38.6	1599	10960
20	Locked	38.6	1656	11062
21	Locked	38.6	1765	11680
22	Locked	38.6	2939	10697
23	Locked	38.9	2635	11095

The Post RS Errors look to be v high.