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rcardo66
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Wednesday, November 8th, 2023 2:33 AM

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Extremely Unreliable Internet (1200Mbps subscriber getting 10Mbps!)

Hello - For the first 2 years moving into this house, I never had issues with my internet however starting around the middle of this year, I suddenly started having extremely unreliable internet. I am subscribed to the 1200Mbps package yet I am seeing speeds anywhere from 10Mbps to 60Mbps connecting directly via ethernet to my laptop (normally I use a Google Nest router). At times it seems like I'm getting disconnected and it becomes unusable. My original modem worked great for the first 2 years (Motorola MB8611) but after the issues started without changing anything in my house, I purchased an Arris S33 but the problems continued. I've had numerous calls to Xfinity and one tech out a couple months ago, which he said he replaced a cable outside but the problems have persisted. Xfinity suggested calling the modem manufacturer, which I just did today and they're telling me the signals are not in spec at all and its Xfinity's issue. I am waiting for another follow up text from Xfinity to see if they'll send another tech but wanted to see what folks on here thought of my modem logs below. Any help is appreciated. Thanks!

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
20 Locked QAM256 543000000 Hz -13 dBmV 36 dB 205150 103104
13 Locked QAM256 501000000 Hz -11 dBmV 38 dB 0 0
14 Locked QAM256 507000000 Hz -10 dBmV 39 dB 0 0
15 Locked QAM256 513000000 Hz -10 dBmV 39 dB 0 0
16 Locked QAM256 519000000 Hz -10 dBmV 39 dB 0 0
17 Locked QAM256 525000000 Hz -10 dBmV 39 dB 0 0
18 Locked QAM256 531000000 Hz -12 dBmV 38 dB 0 0
19 Locked QAM256 537000000 Hz -12 dBmV 38 dB 0 0
21 Locked QAM256 549000000 Hz -15 dBmV 35 dB 2 0
22 Locked QAM256 555000000 Hz -15 dBmV 35 dB 0 0
23 Locked QAM256 561000000 Hz -17 dBmV 33 dB 0 0
24 Locked QAM256 567000000 Hz -16 dBmV 33 dB 0 0
25 Locked QAM256 573000000 Hz -17 dBmV 33 dB 1 0
26 Locked QAM256 579000000 Hz -18 dBmV 32 dB 1 0
27 Locked QAM256 585000000 Hz -17 dBmV 33 dB 0 0
28 Locked QAM256 591000000 Hz -18 dBmV 32 dB 0 0
29 Locked QAM256 597000000 Hz -17 dBmV 33 dB 2 0
30 Locked QAM256 603000000 Hz -17 dBmV 33 dB 0 0
31 Locked QAM256 609000000 Hz -18 dBmV 32 dB 1 0
32 Locked QAM256 615000000 Hz -18 dBmV 32 dB 0 0
33 Locked QAM256 621000000 Hz -21 dBmV 29 dB 12940 0
34 Locked QAM256 627000000 Hz -22 dBmV 28 dB 473563 0
35 Locked QAM256 633000000 Hz -23 dBmV 27 dB 8286823 681
37 Locked QAM256 645000000 Hz -25 dBmV 26 dB 67011587 85000239


Upstream Bonded Channels
Channel ID Lock Status US Channel Type Frequency Width Power
1 Locked SC-QAM 16400000 Hz 6400000 46.3 dBmV
2 Locked SC-QAM 22800000 Hz 6400000 46.8 dBmV
3 Locked SC-QAM 29200000 Hz 6400000 47.0 dBmV
4 Locked SC-QAM 35600000 Hz 6400000 47.0 dBmV

LOG:
18:00:16 3 CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969
18:00:21 3 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
31/12/1969
18:00:23 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
31/12/1969
18:00:23 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
31/12/1969
18:00:23 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-21.1, 5-85MHz.
31/12/1969
18:00:37 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969
18:00:37 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
6/11/2023
22:30:59 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
6/11/2023
22:31:12 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
6/11/2023
22:41:13 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
00:57:12 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
01:07:14 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
01:27:16 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
01:57:27 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
02:17:29 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
02:37:31 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
02:47:32 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
02:57:33 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
03:07:35 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
03:17:37 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
03:37:39 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
03:47:39 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
03:57:41 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
04:07:42 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
04:17:43 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
04:37:45 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
04:47:46 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
04:57:48 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
05:17:49 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
05:27:50 3 UCD invalid or channel unusable;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:00:46 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:00:58 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:01:01 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:01:10 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:01:16 3 Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:02:10 3 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=REMOVED;CMTS-MAC=REMOVED;CM-QOS=1.1;CM-VER=3.1;
7/11/2023
07:02:17 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.2, 258MHz.
7/11/2023
07:02:17 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-21.3, 1002MHz.
7/11/2023
07:02:18 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-21.1, 5-85MHz.
7/11/2023
07:02:31 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
7/11/2023
07:02:31 3 CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
7/11/2023
07:02:33 3 CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.

Question

 • 

Updated 

2 years ago

98

2

0

EG

Expert

 • 

110.4K Messages

2 years ago

The downstream power is too low / out of spec as are many of the SNR's. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

Here is some self-troubleshooting stuff that you can try, but since you already had a tech out, you may want to get them involved again until things are fixed properly.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

And bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.


Good luck with it !

(edited)

1

0

rcardo66

3 Messages

@EG​ Thank you! I was able to set up a 2nd visit for a tech to visit for Friday so we’ll see what happens. In the meantime, I’ll try some of those steps you’ve mentioned. Also thanks for the info on the escalation point. The first tech that came out just said he did not see any more issues after he replaced a cable outside and suggested I buy another modem (even though this would be the 3rd modem so clearly not the issue). I’ll be more prepared this time as it sounds like there could be other cabling he could take a look at (for example, he did not check the one on the pole).

2 years ago

0

EG

Expert

 • 

110.4K Messages

2 years ago

You're welcome ! Please post back here with how things turn out.

2

0

rcardo66

3 Messages

Hello again - Apologies if the formatting is off, I’m having to post this on my phone as the forums not letting me post from my laptop. The second tech came yesterday and ran more tests, showed him the logs and saw how bad the signal was. He replaced some of the coaxial outside and then also replaced the line that drops from the post buried underground. Signals look much better from my understanding and the speed/reliability seems to have improved. However, I was still only seeing about 550Mbps directly via Ethernet when he left (paying for 1200) and today the max I’m seeing is about 250Mbps. He mentioned the only other thing he could have done was replace one other coaxial outside but didn’t think that would improve anything as he was getting over 1000 when he tried with his gadget directly on the coaxial (no modem). Although service has improved, I’m not sure what else could be done to improve the speed to get closer to what I’m paying for. I see the OFDM PLC Channel below has some uncorrectables but not sure if that could be the issue. I also really don’t think it’s the modem as this is a new S33 and my previous Motorola was seeing the same issue. Any help is appreciated! 

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
20 Locked QAM256 543000000 Hz 4 dBmV 44 dB 0 0
1 Locked QAM256 429000000 Hz 3 dBmV 44 dB 0 0
2 Locked QAM256 435000000 Hz 3 dBmV 44 dB 0 0
3 Locked QAM256 441000000 Hz 3 dBmV 44 dB 0 0
4 Locked QAM256 447000000 Hz 3 dBmV 44 dB 0 0
5 Locked QAM256 453000000 Hz 3 dBmV 44 dB 0 0
6 Locked QAM256 459000000 Hz 4 dBmV 44 dB 0 0
7 Locked QAM256 465000000 Hz 4 dBmV 44 dB 0 0
8 Locked QAM256 471000000 Hz 4 dBmV 44 dB 0 0
9 Locked QAM256 477000000 Hz 4 dBmV 44 dB 0 0
10 Locked QAM256 483000000 Hz 4 dBmV 44 dB 0 0
11 Locked QAM256 489000000 Hz 4 dBmV 44 dB 0 0
12 Locked QAM256 495000000 Hz 4 dBmV 44 dB 0 0
13 Locked QAM256 501000000 Hz 4 dBmV 44 dB 0 0
14 Locked QAM256 507000000 Hz 4 dBmV 44 dB 0 0
15 Locked QAM256 513000000 Hz 4 dBmV 44 dB 0 0
16 Locked QAM256 519000000 Hz 4 dBmV 44 dB 0 0
17 Locked QAM256 525000000 Hz 4 dBmV 44 dB 0 0
18 Locked QAM256 531000000 Hz 4 dBmV 44 dB 0 0
19 Locked QAM256 537000000 Hz 4 dBmV 44 dB 0 0
21 Locked QAM256 549000000 Hz 4 dBmV 44 dB 0 0
22 Locked QAM256 555000000 Hz 4 dBmV 44 dB 0 0
23 Locked QAM256 561000000 Hz 4 dBmV 44 dB 0 0
24 Locked QAM256 567000000 Hz 4 dBmV 44 dB 0 0
25 Locked QAM256 573000000 Hz 4 dBmV 44 dB 0 0
26 Locked QAM256 579000000 Hz 4 dBmV 44 dB 0 0
27 Locked QAM256 585000000 Hz 4 dBmV 44 dB 0 0
28 Locked QAM256 591000000 Hz 4 dBmV 44 dB 0 0
29 Locked QAM256 597000000 Hz 4 dBmV 44 dB 0 0
30 Locked QAM256 603000000 Hz 4 dBmV 44 dB 0 0
31 Locked QAM256 609000000 Hz 4 dBmV 43 dB 0 0
32 Locked QAM256 615000000 Hz 4 dBmV 44 dB 0 0
193 Locked OFDM PLC 957000000 Hz 0 dBmV 41 dB 123254750 87



Upstream Bonded Channels
Channel ID Lock Status US Channel Type Frequency Width Power
1 Locked SC-QAM 16400000 Hz 6400000 42.5 dBmV
2 Locked SC-QAM 22800000 Hz 6400000 42.5 dBmV
3 Locked SC-QAM 29200000 Hz 6400000 42.3 dBmV
4 Locked SC-QAM 35600000 Hz 6400000 42.5 dBmV

2 years ago

0

XfinityAngie

Official Employee

 • 

1.9K Messages

@rcardo66, Thank you for reaching out to Xfinity Support! I would like to take a closer look at your account. Please send us a DM with your name and full address.

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2 years ago

0

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