Visitor
•
13 Messages
Random router reboots
I'm on a 1.2 gig plan and my router was shipped, new, to me less than a month ago. Speeds are fantastic, but in the last week or two it's been randomly rebooting, which is a pain. I haven't yet found a pattern to the reboots (time of day, uptime, etc), but when it comes back, the connection time to the Xfinity network is definitely starting at 0h 0m 0s.
Logging on the device is so limited that I cannot do substantial troubleshooting. Below are the connection metrics shortly after the latest reboot:
Cable Modem
HW Version:2.0
Vendor:Technicolor
BOOT Version:S1TC-3.81.21.97
Core Version:1.0
Model:CGM4981COM
Product Type:XB8
Flash Part:4096 MB
Download Version:Prod_22.2_d31 & Prod_22.2
Downstream
|
Channel Bonding Value | ||||||||||||||||||||||||||||||||
Channel ID |
41
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
21
|
22
|
23
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
31
|
32
|
33
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
42
|
43
|
44
|
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
|
Frequency |
669 MHz
|
489 MHz
|
495 MHz
|
507 MHz
|
513 MHz
|
519 MHz
|
525 MHz
|
531 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
|
657 MHz
|
663 MHz
|
675 MHz
|
681 MHz
|
687 MHz
|
722000000
|
SNR |
38.5 dB
|
39.2 dB
|
39.3 dB
|
39.0 dB
|
39.2 dB
|
39.3 dB
|
39.0 dB
|
39.0 dB
|
39.0 dB
|
39.0 dB
|
39.0 dB
|
38.7 dB
|
38.7 dB
|
38.6 dB
|
38.6 dB
|
38.6 dB
|
38.6 dB
|
38.7 dB
|
38.7 dB
|
38.5 dB
|
38.6 dB
|
38.6 dB
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38.5 dB
|
38.5 dB
|
38.5 dB
|
38.7 dB
|
38.5 dB
|
38.6 dB
|
38.6 dB
|
37.9 dB
|
38.4 dB
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38.3 dB
|
38.3 dB
|
Power Level |
-4.8 dBmV
|
-4.5 dBmV
|
-4.0 dBmV
|
-4.6 dBmV
|
-4.5 dBmV
|
-4.2 dBmV
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-4.6 dBmV
|
-4.8 dBmV
|
-4.4 dBmV
|
-4.3 dBmV
|
-4.3 dBmV
|
-4.7 dBmV
|
-4.8 dBmV
|
-4.9 dBmV
|
-5.1 dBmV
|
-5.2 dBmV
|
-4.9 dBmV
|
-4.4 dBmV
|
-4.5 dBmV
|
-4.8 dBmV
|
-5.0 dBmV
|
-4.9 dBmV
|
-4.9 dBmV
|
-4.8 dBmV
|
-4.7 dBmV
|
-4.3 dBmV
|
-4.6 dBmV
|
-4.6 dBmV
|
-4.5 dBmV
|
-5.0 dBmV
|
-4.9 dBmV
|
-4.9 dBmV
|
-4.5 dBmV
|
Modulation |
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
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256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
|
256 QAM
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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
|
*Channel ID 41 is the Primary channel
Upstream
|
Channel Bonding Value | ||||||
Channel ID |
1
|
2
|
3
|
4
|
5
|
6
|
|
---|---|---|---|---|---|---|---|
Lock Status |
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
Locked
|
|
Frequency |
10 MHz
|
16 MHz
|
22 MHz
|
29 MHz
|
35 MHz
|
40 MHz
|
|
Symbol Rate |
2560
|
5120
|
5120
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5120
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5120
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2560
|
|
Power Level |
48.0 dBmV
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48.0 dBmV
|
49.0 dBmV
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49.5 dBmV
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49.0 dBmV
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49.5 dBmV
|
|
Modulation |
QAM
|
QAM
|
QAM
|
QAM
|
QAM
|
QAM
|
|
Channel Type |
ATDMA
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ATDMA
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ATDMA
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ATDMA
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ATDMA
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ATDMA
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CM Error Codewords | |||||||||||||||||||||||||||||||||
Channel ID |
41
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13
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14
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15
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16
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17
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18
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19
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20
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21
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22
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23
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24
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25
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26
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27
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28
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29
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30
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31
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32
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33
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34
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35
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36
|
37
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38
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39
|
40
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42
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43
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44
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159
|
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Unerrored Codewords |
3581142
|
4223623
|
4212833
|
4233144
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4238059
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4242424
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4246976
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4251991
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4257051
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4261498
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4266298
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4270842
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4274975
|
4279179
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4283933
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4288154
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4292974
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4297331
|
4299711
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4304701
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4308692
|
4312883
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4317054
|
4321798
|
4325953
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4330308
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4334178
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4339034
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4343332
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4347424
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4367532
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4350716
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3581142
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Correctable Codewords |
1187647
|
0
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0
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0
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0
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0
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0
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0
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0
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0
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0
|
0
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0
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0
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0
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0
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0
|
0
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0
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0
|
0
|
0
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0
|
0
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0
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0
|
0
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0
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0
|
0
|
0
|
0
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1187647
|
Uncorrectable Codewords |
0
|
0
|
0
|
0
|
0
|
0
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0
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0
|
0
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0
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0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
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0
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0
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0
|
0
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0
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0
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0
|
0
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0
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0
|
0
|
0
|
Please advise. (Please don't advise me to reboot it. We're past that.)
EG
Expert
•
105.6K Messages
6 months ago
The upstream power is borderline high and it may be intermittently fluctuating even higher to out-of-spec levels. The downstream power is on the weak side as well. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
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.
Good luck !
1
EG
Expert
•
105.6K Messages
6 months ago
Yes. Please do post back with an update.
0
0
Bierp
Visitor
•
13 Messages
6 months ago
It's been very easy for me to avoid looking into this in more detail and to just start swearing at it when it resets, but I did just move the router to a different location in the house, closer to the house feed. I'll see if I can identify the cable routing and any splitters, eventually, but at a glance, here are the metrics at the new location. The connection speed is fantastic, clocking 1298 Mbps down and 41 up through speedtest.net.
0
0
EG
Expert
•
105.6K Messages
6 months ago
It's a bit better but the upstream power is still marginal. Not much wiggle room there.
0
0
Bierp
Visitor
•
13 Messages
6 months ago
I had to step out for a few hours, but as I look now, the uptime is 1h 50m, so it clearly reset.
Guess I'll have to actually dig into this.
0
0
EG
Expert
•
105.6K Messages
6 months ago
Please revisit my earlier *things to try* post. If it turns out that there is nothing more that can be done to improve the connection quality, then you'll need a tech visit as stated.
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 !
0
0
Bierp
Visitor
•
13 Messages
6 months ago
Appreciate the input. I'll definitely be working through your post. Just need to carve out some time.
0
0
Bierp
Visitor
•
13 Messages
6 months ago
Ok, so I checked the external setup. Looking past a lot of "legacy" cabling, the current setup seems to be the lead to the house, run through a multi-room filter, a 12ish inch output from that to a 3-way SV-3BG Commscope splitter. Each output on the splitter says -5.5dB.
The room I moved my router to yesterday was the closest, most direct connection. However, as I have no need for coax connections in any other room, I took the splitter out of the sequence and took the cable to that room and ran it directly into the filter. I don't know if the filter can come off if we're not using multi-room, but was reluctant to try it as it say, pretty clearly, do not remove. Obviously that's subjective, but input on this would be great.
I can't tell the quality of the cable from there to the room. It's been painted over and I'm not seeing any writing on the jacket. It appears to be a heavier grade than some of the older, unused coax around the house.
I've reset my router and here's what I'm getting now.
Thoughts?
2
0
Bierp
Visitor
•
13 Messages
6 months ago
It seems to be an MoCA POE filter. Here's an amazon link to one which looks pretty much the same, but may not be the exact part number. (My photo makes it hard for me to get the exact part and it's dark, so I'll have to take a better photo tomorrow.)
https://www.amazon.com/GLP-1G70CWWS-Filter-Eliminate-Multi-Room-Interference/dp/B08HJ4F4D4
The bad news is, even with the improved numbers, the connection has reset several times in the last 30 hours. Sigh.
I can remove it, but not sure whether that'll do much. I can also test it right at the line to the house, removing the cable into the room. Not confident of either, but those are the obvious troubleshooting steps before I have a tech come out.
0
0
EG
Expert
•
105.6K Messages
6 months ago
Try doing both for a test. But put the filter back afterwards, or replace it if it appears to be malfunctioning.
0
0
Bierp
Visitor
•
13 Messages
6 months ago
Sorry, took me a while to get around to this.
I've done several tests. The upstream on all of them seemed to be the same across the board, at 42.3, 42.3, 42.8, 43.3, 43.3 and 43.3 dBmV.
The downstream on channel 41 varied based on the conditions. The SNR was 39.2 or 39.3 consistently. The power broke down like this:
Upstairs, filtered: 4.4 dBmV
Upstairs, unfiltered: 5.2 dBmV
Directly on the line, filtered: 5.7 dBmV
Directly on the line, unfiltered: 6.0 dBmV
So clearly I've got some reduction on the line running upstairs and clearly the filter has an impact as well.
Right now I'm setup with Upstairs, unfiltered at 5.2. I don't especially want to run for any length on the direct connection as that involves leaving hardware outside, or wrangling with windows and screens. (Though I CAN do this if we get to that point.)
The filter in question has a sticker on it which says "Required for Multi-room DVR - Do Not Remove". I don't have any DVR, so I don't think I really need that. The engraved coding on the side says:
GLP-1G70CWWS
PPC 3321A
Anything after the S on the first line will be hidden by the sticker.
So my plan is to run on the 5.2 dBmV connection for a bit to see how it behaves. I'll then setup for a direct connection at 6.0 dBmV. Anything further probably exceeds my troubleshooting ability, barring additional instructions.
Let me know what you think, and thanks again for your help.
0
0
Bierp
Visitor
•
13 Messages
6 months ago
Made it about 30 hours before it crashed. Sigh.
0
0
Bierp
Visitor
•
13 Messages
6 months ago
Ok, I've setup a direct connection from the Comcast lead to the router. Fingers crossed, but not optimistic. This will be my last possible troubleshooting step before I have to have them out.
Here are the metrics right now.
2
0
Bierp
Visitor
•
13 Messages
6 months ago
Uptime is 52 hours and counting, which is encouraging. It's possible that the older cabling in this place is the problem.
So my question is, can Comcast set me up with an appropriate, modern cable to a central room? My external hookup is very kludgy and definitely not a good permanent solution.
I'm renting this place if that matters.
Let me know, please.
5
0