T3 timeouts and other fun

Network Log

Time Priority Description

As noted at the top of my post, you can see where the channel dropped out with the "Started Unicast Maintenance Ranging" messages being spammed.
I know a few T3's is completely fine, i'm more worried about the bursts they've been coming in recently.

I'd love this to get looked into/resolved - cheers in advance!

The RS count may have reset because you were disconnected. Looks like you've upstream noise on the channel centered at 43.1 MHz, probably towards the higher end, with noise also above and, to a lesser extent, below there.

This should show in the upstream SNR values. These do not require you to be in router mode to be obtained. This will be impacting everyone in your local area if this is the case.

Just to respond to what the Forum Team observed about modem mode, and to back up what IPFreely said (he really knows his a stuff), if it’s T3 events that are of concern, there’s nothing other than your hub that they need to look at.  The behaviour of your router is totally irrelevant.

The stats are a point-in-time snapshot and the only pointer towards possible modulation changes is the T3 event count.  I note that no T4 events are reported and that there is thus no history recorded of 16x T3 on the trot that would have caused a reset. 

You haven’t said what real-life issues you are experiencing.  T3 events normally occur in the background and shouldn’t affect your experience.

Just to make sure that the T3 timeout event is understood. It occurs if an expected keep-alive message is not received at the CMTS (the VM end).  If there are 16x of these on the trot, the hub will reset (a T4 event).

If you've had an instance of losing an upstream channel, then the problem's in the Network.   Quite how you get the VM bods on this forum to get that dealt with is quite a challenge because the instants that they look at your situation, everything looks normal.    Of course the data's all there in the CMTS logs, to which, AFAIK, the Forum Team don't have access.

Here's the potential problem with the Forum Team reply.

If you are still seeing the reduced upstream modulation (as in 16QAM, 32QAM), then your upstream is experiencing noise on those channels.  The CMTS at the VM end adjusts the modulation downwards so that the upstream data received can be used.  If 16QAM doesn't cut it, a modem rest will occur.

The Forum Team will have been briefed that this is normal behaviour (which, in DOCSIS terms it is).  Never mind the disrupted upstream, poor performance and so on.

So, until Networks resolve the noise issue (and who's gonna invoke that effort), you're stuffed, imo.

If you still suffer 16QAM/32QAM upstream modulation, then modem mode is neither here not there.

On the other hand, because the Forum Team are briefed that these modulation levels are normal behaviour, they're probing as to how that impacts your actual broadband experience.

Lets be clear about a couple of things:

1/

If you have reduced upstream modulation all the time, your uploads would be slower and particularly at peak times, there would be demand contention with neighbours suffering the same issue (always worth checking with a neighbour or two).

2/

When the Forum Team look at your circuit, they either looking at a point in time or, if you are lucky, they are monitoring at various points.  When you post your modem stats, you're doing the same thing.  There are no logs in the Hub other than those you and they can see.

3/

Because you lose the upstream entirely, the Forum Team should be concerned with that.  Such events should be recorded in the CMTS logs (I think I'm correct there).  I hope that the FT go one step further and ask Networks to take a look.  The request will need to come from you.

@ForumTeam

Why don't you fully explain why you want to put the OP to the awkward trouble of going into router mode?  What tests do you need to perform that you can't perform in modem mode?  What's the big secret?  IT'S THE UPSTREAM that's the problem and this has nothing to do with modem mode.  

Do the wonderful VIPs on the Forum know the answer to my question?

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Icantcrabhere wrote:

Hi there,
noticed over the past few weeks that i'm getting random bursts of T3 timeouts,
also yesterday in the morning, I lost a whole upstream channel - rebooting restored this, however it still isn't a good sign.

I've checked both the online fault checker and the phone version:

Yesterday the online fault checker showed no issues in my area. - then I clicked the "test your hub" option.
It showed "intermittent signal in your area" - but today it's back to normal, showing just the standard "We couldn't find an issue, let's try resetting the hub!" style message.
However this is far from the case, clearly.

I'll share my fresh stats from the restart yesterday, these are from after 12PM yesterday afternoon.

I'll have to split the post due to character limits.

Firstly, BQM live graph:(Nothing much to see here, just for future reference)

https://www.thinkbroadband.com/broadband/monitoring/quality/share/1700d27c199ce3ea214d66ce063ff9f395507b3e

 

Downstream bonded channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	539000000	0.5	38	256 qam	17
2	547000000	0.2	38	256 qam	18
3	555000000	0	38	256 qam	19
4	563000000	-0.2	38	256 qam	20
5	571000000	-0.5	38	256 qam	21
6	579000000	-0.4	38	256 qam	22
7	587000000	0	38	256 qam	23
8	595000000	0.5	38	256 qam	24
9	603000000	0.4	38	256 qam	25
10	611000000	0.2	38	256 qam	26
11	619000000	-0.4	38	256 qam	27
12	627000000	-0.5	38	256 qam	28
13	635000000	-0.5	37	256 qam	29
14	643000000	-0.2	38	256 qam	30
15	651000000	0.2	38	256 qam	31
16	659000000	0.5	38	256 qam	32
17	667000000	0.5	38	256 qam	33
18	675000000	0.2	38	256 qam	34
19	683000000	-0.2	38	256 qam	35
20	691000000	-0.2	38	256 qam	36
21	699000000	-0.4	37	256 qam	37
22	707000000	0	37	256 qam	38
23	715000000	-0.4	37	256 qam	39
24	723000000	-0.5	38	256 qam	40

Downstream bonded channels

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

1	Locked	38.6	30	0
2	Locked	38.6	38	0
3	Locked	38.9	44	0
4	Locked	38.9	43	0
5	Locked	38.6	68	0
6	Locked	38.9	47	0
7	Locked	38.6	37	0
8	Locked	38.6	22	0
9	Locked	38.9	18	0
10	Locked	38.6	61	0
11	Locked	38.6	90	0
12	Locked	38.6	125	0
13	Locked	37.6	121	0
14	Locked	38.6	78	0
15	Locked	38.9	58	0
16	Locked	38.6	61	0
17	Locked	38.6	48	0
18	Locked	38.6	78	0
19	Locked	38.6	126	0
20	Locked	38.6	136	0
21	Locked	37.6	110	0
22	Locked	37.6	78	0
23	Locked	37.6	108	0
24	Locked	38.6	124	0

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

1	49600258	45	5120	64 qam	1
2	36600000	44.3	5120	64 qam	3
3	23600000	43.8	5120	64 qam	5
4	30100258	44	5120	64 qam	4
5	43100000	44.5	5120	64 qam	2

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1	ATDMA	0	0	1	0
2	ATDMA	0	0	1	0
3	ATDMA	0	0	0	0
4	ATDMA	0	0	0	0
5	ATDMA	0	0	2	0

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Do you think you will get an answer to this?