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Occasional spikes in latency. Getting pre RS errors on ALL downstream channels.

mrhcarlin
On our wavelength

Hello!

I'm not sure how long this has been an issue, but probably only a few days at most. I've been away since Thursday and I don't recall having issues earlier last week, but yesterday evening while gaming online I noticed (and felt) that my in game latency was spiking. Afterwards I performed a lengthy ping test and would see spikes up to and around 300ms for a few seconds.

For example:

Reply from 1.1.1.1: bytes=32 time=17ms TTL=56
Reply from 1.1.1.1: bytes=32 time=20ms TTL=56
Reply from 1.1.1.1: bytes=32 time=17ms TTL=56
Reply from 1.1.1.1: bytes=32 time=248ms TTL=56
Reply from 1.1.1.1: bytes=32 time=233ms TTL=56
Reply from 1.1.1.1: bytes=32 time=312ms TTL=56
Reply from 1.1.1.1: bytes=32 time=298ms TTL=56
Reply from 1.1.1.1: bytes=32 time=22ms TTL=56
Reply from 1.1.1.1: bytes=32 time=18ms TTL=56
Reply from 1.1.1.1: bytes=32 time=17ms TTL=56

So I'd get these high spikes every now and then, maybe every minute or so but sometimes in more frequent succession, and then it would settle back down.

I logged into my Hub5 (I'm on Gig1) and noticed that ALL 31 channels under 3.0 Downstream were seeing Pre RS Errors - some quite significant by the looks of it (18 and 19). Channel 12 is also seeing Post RS Errors.

Below is my output at time of writing.

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

1Locked40460
2Locked4070
3Locked4070
4Locked4050
5Locked4050
6Locked4080
7Locked40120
8Locked4080
9Locked40120
10Locked40190
11Locked40260
12Locked40119110
13Locked38270
14Locked40300
15Locked40290
16Locked40180
17Locked40310
18Locked401731790
19Locked3912119720
20Locked40770
21Locked40490
22Locked40490
23Locked40580
24Locked40390
25Locked40520
26Locked40530
27Locked40550
28Locked40760
29Locked40690
30Locked40530
31Locked401330

Downstream power and SNR looks normal though, but correct me if I'm wrong.

 

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
1331000000-2.340QAM 25625
21550000002.140QAM 2563
31630000001.740QAM 2564
41710000001.140QAM 2565
51790000000.940QAM 2566
61870000000.540QAM 2567
71950000000.240QAM 2568
82030000000.240QAM 2569
92110000000.440QAM 25610
10219000000-140QAM 25611
11227000000-1.140QAM 25612
12235000000-1.240QAM 25613
13243000000-1.638QAM 25614
14251000000-1.840QAM 25615
15259000000-1.940QAM 25616
16267000000-2.140QAM 25617
17275000000-2.640QAM 25618
18283000000-2.840QAM 25619
19291000000-339QAM 25620
20299000000-2.840QAM 25621
21307000000-2.240QAM 25622
22315000000-2.140QAM 25623
23323000000-2.440QAM 25624
24339000000-240QAM 25626
25347000000-240QAM 25627
26355000000-240QAM 25628
27363000000-1.940QAM 25629
28371000000-2.340QAM 25630
29379000000-2.340QAM 25631
30387000000-2.340QAM 25632
31395000000-2.740QAM 25634

Not entirely sure what the other two downstream tables are showing, but here's their outputs as well.

3.1 Downstream channels

Channel Channel Width (MHz) FFT Type Number of Active Subcarriers Modulation (Active Profile) First Active Subcarrier (Hz)
33944K1840QAM 40961108

3.1 Downstream channels

Channel ID Locked Status RxMER Data (dB) PLC Power (dBmV) Corrected errors (Active Profile) Uncorrectable errors (Active Profile)
33Locked38-10.112560432838

Not sure if those "corrected" and "uncorrectable" errors are anything to be concerned about.

Upstream page as well:

3.0 Upstream channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
04960000048.35120QAM 641
14310000048.35120QAM 642
236600000485120QAM 643
33010000047.55120QAM 644
423600000475120QAM 645

3.0 Upstream channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
0ATDMA0000
1ATDMA0000
2ATDMA0000
3ATDMA0000
4ATDMA0000

3.1 Upstream channels

Channel Channel Width (MHz) Power (dBmV) FFT Type Modulation
610.444.22KQAM 256

3.1 Upstream channels

Channel Channel Type Number of Active Subcarriers First Active Subcarrier (Hz) T3 Timeouts T4 Timeouts
6OFDMA2087400000000

...

So looks like something might be off about the downstream.

The Hub has been restarted and the issue persists.

If someone could kindly help that'd be much appreciated.

 

Thanks.

2 REPLIES 2

legacy1
Alessandro Volta

setup a BQM for router mode but before that test with a PC and hub in modem mode 

Broadband Quality Monitor | thinkbroadband

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Sabrina_B
Forum Team
Forum Team

Hi @mrhcarlin 👋👋.

Thanks for reaching out to us. Apologies for the issues that you are having with Pre RS errors. Can we ask since your post, is the issue still ongoing or have you been able to resolve this, please let us know.

Sabrina