Community Forum

Intermittent connection (random quick disconnects)

Highlighted
Regular Visitor

Intermittent connection (random quick disconnects)

Hi, I just moved to a new house and signed up with Comcast for the 400 mbps plan they have.

 

Since the beginning (1month+ a go) I'm suffering with random disconnects. I used an app to track it for a while and the average is 24 disconnects per day (not necessarily 1 per hour)

 

e.g 

 

7/25/2019 9:18:32 AM 0:00:07
7/25/2019 9:20:48 AM 0:00:40
7/25/2019 9:22:11 AM 0:00:24
7/25/2019 12:58:01 PM 0:00:05
7/25/2019 12:59:56 PM 0:00:05
7/25/2019 2:13:25 PM 0:00:07
7/25/2019 2:39:11 PM 0:00:06
7/25/2019 2:40:32 PM 0:00:10
7/25/2019 2:56:50 PM 0:00:09
7/25/2019 3:32:08 PM 0:00:06
7/25/2019 3:35:51 PM 0:00:09
7/25/2019 3:40:41 PM 0:00:13
7/25/2019 3:41:58 PM 0:00:06
7/25/2019 3:45:10 PM 0:00:10
7/25/2019 3:52:53 PM 0:00:09
7/25/2019 3:59:13 PM 0:00:07
7/25/2019 4:09:58 PM 0:00:08
7/25/2019 4:14:56 PM 0:00:08
7/25/2019 4:35:05 PM 0:00:05
7/25/2019 4:36:13 PM 0:00:05
7/25/2019 5:44:25 PM 0:00:07
7/25/2019 5:55:36 PM 0:01:36
7/25/2019 5:58:06 PM 0:00:06
7/25/2019 6:17:44 PM 0:01:30

 

I had techs visiting 3 times already.

  • The first one just moved the modem to the second floor where the office is.
  • The second detected a lot of noise in the box outside coming from a cable that he coundn't identify. According to him he removed that cable an installed filters in all the lines there.
  • Third tech detected errors on the juction from the first floor to the second floor (I live in small town house) and recommended that I should replace the cable that goes to the second floor

I followed his recommendation and replaced that parte of the cable for a new one BUT the problem still persists. 

 

The wierd part is that I get the full 400 mbps or pretty close in almost all the speed tests but I cant play anything online or watch any streams like Twich without random disconnections.

 

I can still see a lot of Uncorrectable errors in the modem

 

XFINITY Network

Internet:Active
Local time:2019-08-07 20:23:06
System Uptime:0 days 0h: 21m: 22s
WAN IP Address (IPv4):73.115.115.238
WAN Default Gateway Address (IPv4):73.115.112.1
WAN IP Address (IPv6):2001:558:6022:8f:74f8:c2bf:e481:ff3a
WAN Default Gateway Address (IPv6):fe80::256:2bff:fe77:1c22
Delegated prefix (IPv6):2601:2c0:8600:a72::/64
Primary DNS Server (IPv4):75.75.75.75
Secondary DNS Server (IPv4):75.75.76.76
Primary DNS Server (IPv6):2001:558:feed::1
Secondary DNS Server (IPv6):2001:558:feed::2
WAN Link Local Address (IPv6):fe80::966a:77ff:fe66:1827
DHCP Client (IPv4):Enabled
DHCP Client (IPv6):Enabled
DHCP Lease Expire Time (IPv4):3d:1h:17m
DHCP Lease Expire Time (IPv6):49710d:6h:28m
WAN MAC:94:6A:77:66:18:27
eMTA MAC:94:6A:77:66:18:26
CM MAC:94:6A:77:66:18:25

Initialization Procedure

Initialize Hardware:Complete
Acquire Downstream Channel:Complete
Upstream Ranging:Complete
DHCP bound:Complete
Set Time-of-Day:Complete
Configuration File Download:Complete
Registration:Complete

Cable Modem

HW Version:2.2
Vendor:Technicolor
BOOT Version:S1TC-3.49.18.14
Core Version:1.0
Model:CGM4140COM
Product Type:XB6
Flash Part:8192 MB
Download Version:Prod_18.1_d31 & Prod_18.1
Serial Number:152930068502311897
Downstream
Channel Bonding Value
Index
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
159
 
Lock Status
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Frequency
465 MHz
471 MHz
477 MHz
483 MHz
489 MHz
495 MHz
501 MHz
507 MHz
513 MHz
519 MHz
525 MHz
531 MHz
537 MHz
543 MHz
549 MHz
555 MHz
561 MHz
567 MHz
573 MHz
579 MHz
585 MHz
591 MHz
597 MHz
603 MHz
609 MHz
615 MHz
621 MHz
627 MHz
633 MHz
639 MHz
645 MHz
651 MHz
690 MHz
611600000
SNR
43.2 dB
43.0 dB
43.0 dB
42.7 dB
42.7 dB
42.4 dB
42.4 dB
42.4 dB
42.2 dB
42.0 dB
42.0 dB
41.8 dB
41.9 dB
41.9 dB
41.7 dB
41.5 dB
41.2 dB
41.0 dB
41.3 dB
41.2 dB
41.3 dB
41.2 dB
41.3 dB
40.9 dB
40.8 dB
40.4 dB
40.3 dB
40.5 dB
40.3 dB
40.5 dB
39.7 dB
39.8 dB
15.1 dB
NA
Power Level
4.4 dBmV
3.8 dBmV
4.0 dBmV
3.5 dBmV
3.2 dBmV
2.8 dBmV
3.0 dBmV
3.2 dBmV
2.6 dBmV
2.4 dBmV
2.0 dBmV
2.4 dBmV
2.2 dBmV
2.6 dBmV
2.3 dBmV
1.8 dBmV
1.2 dBmV
0.9 dBmV
1.6 dBmV
1.3 dBmV
1.8 dBmV
1.5 dBmV
2.0 dBmV
1.1 dBmV
1.0 dBmV
1.0 dBmV
0.7 dBmV
1.0 dBmV
0.6 dBmV
0.9 dBmV
0.4 dBmV
0.3 dBmV
0.1 dBmV
NA
Modulation
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
256 QAM
OFDM
OFDM
Upstream
Channel Bonding Value
Index
1
2
3
4
Lock Status
Locked
Locked
Locked
Locked
Frequency
36 MHz
29 MHz
23 MHz
16 MHz
Symbol Rate
5120
5120
5120
5120
Power Level
45.3 dBmV
45.8 dBmV
46.3 dBmV
47.3 dBmV
Modulation
QAM
QAM
QAM
QAM
Channel Type
ATDMA
ATDMA
ATDMA
ATDMA

 

CM Error Codewords
Index
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Unerrored Codewords
16247921
43500258
43459917
43400523
55405646
55410453
55416626
55421723
55426890
55431216
55436411
55441135
55445195
55450921
55456374
55460906
55468565
55474101
55479879
55485241
55490176
55494519
55498843
55499825
55498344
55495980
55490707
55484623
55472021
55449101
55416475
55372677
16247921
Correctable Codewords
229568
184872
205555
223104
0
0
0
0
0
0
0
0
0
0
0
0
0
45
173
266
779
1965
4228
8683
15242
23492
32014
42783
58148
81321
110437
143390
229568
Uncorrectable Codewords
32294
65936
92344
138215
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
24
194
433
790
2015
3637
6284
12031
21280
37061
32294
Regular Visitor

Re: Intermittent connection (random quick disconnects)

So I had another tech visit this Saturday. He magically found another problem in the house that could be causing the errors in the modem. Guess what? It wasn't.

 

I believe it is something in the neighborhood node but due the fact this problem might not be noticed if you only browse and watch netflix. I might be the only one complaining.

 

I'm still noticing the same behaviour as before. The uncorrectable errors keep pilling up non stop in the modem.

 

Speed test is always good with cable (300 mbps+) but it's impossile do play any online game, use discord or have a conference call.

 

I'm starting to lose hope. It might be time to start looking for alternatives.

 

Any ideas of what I can do?

 

Thanks

Frequent Visitor

Re: Intermittent connection (random quick disconnects)

I'm experiencing the exact same issues currently.

 

Your down-stream levels look sublime. You're above the noise floor (SNR) you should be, and you're within the goldilocks zone of QAM power (-8 to +8 according to comcast).

 

My concern: Keep an eye on those upstream levels.

 

They flucuate with environmental factors, and when they exceed spec (Typically 51-52dBmV) things can disconnect your modem for a quick moment... Just like you're describing. These levels are adjusted by the 'node' or hubsuite of Comcast. It basically tells your modem what levels to be set at for it to appropriately be seen for upstream response. It's possible there's a lot of noise on the 16, 23, 29, and 36 MHz frequencies of your line outside of your home, and the SNR (signal-to-noise ratio) on the upstream is horrible. (You, unfortunately, cannot see upstream SNR. Only they can, as it would be detected/monitored on their equipments side. Conversely, this also applies with your downstream - only you can see your downstream SNR. This is why they have to 'tap into your modem' to see your SNR).

 

I bet if you check immediately after your modem drops, you'll see these levels at or above the 51-52dBmV level. This would give major creedence to your line/node issue.

 

This is when you would need to have a tech in home, and you would adamantly need to request a line-maintenance ticket to be escallated, because you're upstream power levels keep spiking out of spec.

 

((All that said: 

It is possible that there are splitters between your wall-outlet and the Demaraction point of your home. These splitters do add a lot of noise - so making sure there are no  splitters "in the walls" with only a straight run to your comcast ingress point is the best thing you can do. And, unforutnately, this isn't always easy as home builders have no qualms burrying splitters deep to inaccessable locations.))

Expert

Re: Intermittent connection (random quick disconnects)

The signal stats looked o/k at that snapshot in time. Perhaps there is intermittent noise ingress into the line(s) somewhere.

 

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.


I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They can check the CMTS (Cable Modem Termination System) for any real time degradation and / or error reports, see your node / cable plant and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
Regular Visitor

Re: Intermittent connection (random quick disconnects)

@NoTick Thanks for you technical answer.

 

It's a rental house but It does have a splitter that brings the cable from the first to the second floor. I dont think that's the root cause right now because initiially I had the modem in the first floor and I still had problems.

 

I'll be more strict with the next technician that comes here. Specially because just after you reboot the modem you can already notice that uncorrect errors pilling up. I just want to avoid the "everything looks ok, bye" thing again.

 

@EG Thanks. I'll be waiting for them to contact me

Official Employee

Re: Intermittent connection (random quick disconnects)

Hey there, diegorramos84! Thank you for taking the time to reach out to us here on the forums. I definitely understand how important it is to have reliable service, and I'm happy to help. To get started, please send me a PM with your first and last name! 

To send me a Private Message, please click my name “ComcastAlly” and click “Send a message.”


I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!