Solved: Internet disconnecting multiple times per day - Xfinity Help and Support Forums

tsmccull · ‎11-13-2019

Got a notice from Comcast that work was being done in my area on 11/11. Since then, my Xfinity modem will periodically loose internet connectivity, detect that, and resync itself. This is happening multiple times each day with each dropout taking 10 or more minutes to correct itself. Any recommendations on how to find and fix whatever is causing this? Have made no changes to the network for months, so I suspect it's upstream of my system somewhere.

Thad

EG · ‎11-13-2019

What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

What is the exact make and model number of the modem ?

Is this a WiFi connection ?

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tsmccull · ‎11-13-2019

TG1682G Xfinity box with dual-band wifi. Sequence of events appears to be that the box looses connection to the Internet which means both wifi bands do also, the box recognizes that it's not connected and eventually reconnects itself, followed of course by wifi coming back online. It's happened about 4 or 5 times already this morning.

Upstream
Index	1	2	3	4
Lock Status	Locked	Locked	Locked	Locked
Frequency	29.40 MHz	16.60 MHz	23.00 MHz	35.80 MHz
Symbol Rate	5120 KSym/s	5120 KSym/s	5120 KSym/s	5120 KSym/s
Power Level	46.25 dBmV	46.25 dBmV	45.25 dBmV	46.00 dBmV
Modulation	64 QAM	64 QAM	64 QAM	64 QAM
Channel Type	DOCSIS2.0 (ATDMA)	DOCSIS2.0 (ATDMA)	DOCSIS2.0 (ATDMA)	DOCSIS2.0 (ATDMA)

Downstream

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

Lock Status

Locked

Frequency

531.00 MHz

537.00 MHz

543.00 MHz

549.00 MHz

555.00 MHz

561.00 MHz

567.00 MHz

573.00 MHz

579.00 MHz

585.00 MHz

591.00 MHz

597.00 MHz

603.00 MHz

609.00 MHz

615.00 MHz

621.00 MHz

627.00 MHz

633.00 MHz

639.00 MHz

645.00 MHz

651.00 MHz

657.00 MHz

663.00 MHz

669.00 MHz

SNR

38.98 dB

38.61 dB

40.37 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

Power Level

-6.00 dBmV

-6.50 dBmV

-6.40 dBmV

-5.80 dBmV

-6.10 dBmV

-6.00 dBmV

-5.90 dBmV

-6.50 dBmV

-6.80 dBmV

-5.90 dBmV

-6.00 dBmV

-6.10 dBmV

-6.00 dBmV

-6.70 dBmV

-6.90 dBmV

-6.80 dBmV

-7.20 dBmV

-6.90 dBmV

-6.80 dBmV

-7.20 dBmV

-6.90 dBmV

-6.50 dBmV

-6.60 dBmV

-6.20 dBmV

Modulation

256 QAM

EG · ‎11-13-2019

For a test, does a computer hardwired directly to the 1682 with an ethernet cable have the same problem ?

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tsmccull · ‎11-13-2019

Yes. I have a PC directly connected to the Xfinity box via ethernet cable and it also alerts me when it doesn't have internet connectivity. It usually tells me first, and then I'll notice wifi going out throughout the house (OOMA VOIP drops, iPhone looses connection, etc.). Eventually everything will come back up once the Xfinity modem resyncs itself after a while.

EG · ‎11-13-2019

O/k so the signal stats are good. Would you please post the RF error / event log entries too.

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tsmccull · ‎11-13-2019

I would if I could. Under Troubleshooting > Logs, when I click on "Show Logs" for either System, Event or Firewall logs for today, it goes off and shows a "Operation in Progress" msg for 10 or 15 seconds which then goes away, but once that occurs, no logs appear for either Printing or Downloading. It's as though there aren't any. I did make sure I had Internet connectivity when I did this, so I don't know if it's not recording any logs, or they're further upstream and I have no access to them. I also tried to get logs for past time periods; no luck there either.

I've scheduled a technician visit for tomorrow afternoon. Should I keep it and, if so, what should I tell him?

EG · ‎11-13-2019

O/k well we've seen a number of posts here lately that indicate that a recent firmware update pushed by CC may have disabled the error log viewing in some or all of their gateway devices so I'm not surprised that you can't view them. This was a big mistake on their part IMO.......

Yep. Keep the appointment and show the tech this thread if you feel that you need to. I'll add that although it may or may not be the root cause of the issue, point out to the tech that the downstream power levels are a bit on the weak side and that they may be intermittently fluctuating even lower to out of spec levels. Good luck, and please post back with how things turn out.

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tsmccull · ‎11-18-2019

The tech came out today. Didn't find anything obvious wrong, but he did replace an old cable wall outlet and installed an amp in place of the house's 3-way splitter. I'll watch things for a while and see if I see any more dropouts - if they continue he recommended swapping out the gateway (same model) to see if perhaps something's wrong with mine. He thinks it's unlikely, but worth a try if the amp doesn't fix things. Downstream readings are more robust now:

Upstream	Channel Bonding Value
Index	1	2	3	4
Lock Status	Locked	Locked	Locked	Locked
Frequency	29.40 MHz	16.60 MHz	23.00 MHz	35.80 MHz
Symbol Rate	5120 KSym/s	5120 KSym/s	5120 KSym/s	5120 KSym/s
Power Level	37.68 dBmV	37.50 dBmV	37.00 dBmV	37.50 dBmV
Modulation	64 QAM	64 QAM	64 QAM	64 QAM
Channel Type	DOCSIS2.0 (ATDMA)	DOCSIS2.0 (ATDMA)	DOCSIS2.0 (ATDMA)	DOCSIS2.0 (ATDMA)

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

Lock Status

Locked

Not Locked

Frequency

429.00 MHz

435.00 MHz

441.00 MHz

447.00 MHz

453.00 MHz

459.00 MHz

465.00 MHz

471.00 MHz

477.00 MHz

483.00 MHz

489.00 MHz

495.00 MHz

507.00 MHz

513.00 MHz

519.00 MHz

525.00 MHz

531.00 MHz

537.00 MHz

543.00 MHz

549.00 MHz

555.00 MHz

561.00 MHz

567.00 MHz

573.00 MHz

SNR

40.37 dB

40.95 dB

40.37 dB

40.95 dB

40.37 dB

38.98 dB

40.37 dB

40.95 dB

40.37 dB

40.95 dB

40.37 dB

40.95 dB

38.98 dB

38.61 dB

Power Level

1.70 dBmV

1.60 dBmV

1.80 dBmV

1.70 dBmV

1.60 dBmV

1.50 dBmV

1.70 dBmV

1.40 dBmV

1.70 dBmV

1.10 dBmV

1.40 dBmV

1.30 dBmV

1.20 dBmV

1.40 dBmV

0.90 dBmV

0.80 dBmV

1.10 dBmV

0.80 dBmV

0.50 dBmV

-0.10 dBmV

Modulation

256 QAM

EG · ‎11-18-2019

Yep. Looks better. Hope this does the trick for you. Good luck !

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tsmccull · ‎11-22-2019

So far, so good, but I wanted to ask a question about the downstream results I'm seeing. In the mornings, the channel values typically range from around -1.0 dBmv to +1.0 dBmv, while in the afternoons, those same values are always higher, from maybe -0.2 dBmv to +1.8 dBmv (different for different channels). Any thoughts on what might be different in the AM vs. PM?

EG · ‎11-22-2019

Ambient temperature fluctuations cause changes in the resistance of the lines / hardware resulting in signal variations. That fluctuation you posted is very small and not a problem. Under 3 dB of fluctuation is o/k.

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tsmccull · ‎11-22-2019

Thanks for the info. Should be interesting to see what the variation becomes in winter when we sometimes get down to -20 deg. F.

EG · ‎11-22-2019

The AGC (Automatic Gain Control) circuits in the line amplifiers are designed to keep the signal fairly stable regardless of outside conditions. More than a 3-4 dB variation indicates a problem.

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tsmccull · ‎11-23-2019

I suspect that something somewhere must have been causing signal dropouts prior to the tech installing the new amp, since nominal levels pre-amp were typically in the -6 to -8 range and, although low, were usually enough to maintain connectivity most of the time, particularly from mid-day onward. The tech stated that signal levels to the outside connection at the rear of the house were fine, so the amp seems to have compensated for in-house cable losses. That's good and perhaps any continuing signal dropouts (if they exist) are basically benign to my gateway now since it's starting from much higher nominal signal levels.

One thing I have noticed that's different is that before the amp installation I was getting thousands of correctable codeword errors along with hundreds of uncorrectable errors on many channels, while now with the amp inserted, at most I see a couple dozen correctable codeword errors on 4 or 5 channels with zero uncorrectable errors. I assume if external things start acting up again, I'll probably start seeing many more correctable and uncorrectable codeword errors. Does that sound like a good assumption?

EG · ‎11-23-2019

@tsmccull wrote:

I assume if external things start acting up again, I'll probably start seeing many more correctable and uncorrectable codeword errors. Does that sound like a good assumption?

Yes. A more poor quality of the connection will result in more line noise (lower SNR values) / more bit errors.

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tsmccull · ‎11-27-2019

It's a warm day today (> 50 deg.), but it looks like some of the DS signal variations are getting close to your 3 to 4 dB deltas when compared to those I recorded in my 11/18 email (particularly on the higher frequencies):

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

Lock Status

Locked

Frequency

531.00 MHz

537.00 MHz

543.00 MHz

549.00 MHz

555.00 MHz

561.00 MHz

567.00 MHz

573.00 MHz

579.00 MHz

585.00 MHz

591.00 MHz

597.00 MHz

603.00 MHz

609.00 MHz

615.00 MHz

621.00 MHz

627.00 MHz

633.00 MHz

639.00 MHz

645.00 MHz

651.00 MHz

657.00 MHz

663.00 MHz

669.00 MHz

SNR

40.37 dB

38.98 dB

40.37 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

Power Level

-0.10 dBmV

-0.60 dBmV

-0.30 dBmV

-0.50 dBmV

-0.60 dBmV

-0.90 dBmV

-1.50 dBmV

-1.80 dBmV

-1.20 dBmV

-1.30 dBmV

-1.10 dBmV

-1.30 dBmV

-1.90 dBmV

-2.10 dBmV

-2.50 dBmV

-2.10 dBmV

-2.60 dBmV

-2.00 dBmV

-1.90 dBmV

-2.00 dBmV

-1.60 dBmV

Modulation

256 QAM

EG · ‎11-27-2019

Everything is well within spec. Are you still having problems ? If not, don't sweat it.

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tsmccull · ‎12-01-2019

Everything still seems to be working, but I'm starting to see uncorrectable codewords listed by the router for the first time since the amp was installed. DS signal levels remain in the -2 to +0.5 dBmv range on the various channels, at least when I happen to look at them.

Question: without the router's log function working, is there any practical way to monitor what happens over time as far as signal level changes and/or errors seen in the data stream? I assume not, but wanted to ask. Thanks.

EG · ‎12-01-2019

Scripts can be written to poll for and track the modem signal data. You can Google for more info. It may be easier to just monitor them periodically.

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tsmccull · ‎12-03-2019

I used the trial version of pingplotter to monitor some routes in Comcast's network. Didn't see any local issues during those checks, but did see some major data dropouts when going through a Comcast hub in Chicago, but that didn't impact my local connection. However, I am seeing some degradation of the signal levels at my router in the mornings. Right after the tech installed the amp, I was getting levels from around 0 to +1.6 dBmv or so. This morning I'm seeing the following along with over a thousand uncorrectable errors on several channels (the ones with the least signal levels - 7 thru 12 or so). Looks like a relative drop of 4 to 5+ dB over a period of a couple of weeks. I'm not seeing any internet dropouts on my system yet, but if those same fluctuations were occuring when my nominal signal levels were in the -7 to -8 dBmv range prior to the amp, perhaps that's what was causing the router to loose connectivity. Why the signal levels are changing that much is a mystery to me since nothing inside the house has been touched since the tech was here.

I would have thought signal levels would tend to drop at the higher frequency end due to cable losses, etc., but this data implies that there's more loss in the center of the channel frequency band which I find odd.

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

Lock Status

Locked

Frequency

531.00 MHz

537.00 MHz

543.00 MHz

549.00 MHz

555.00 MHz

561.00 MHz

567.00 MHz

573.00 MHz

579.00 MHz

585.00 MHz

591.00 MHz

597.00 MHz

603.00 MHz

609.00 MHz

615.00 MHz

621.00 MHz

627.00 MHz

633.00 MHz

639.00 MHz

645.00 MHz

651.00 MHz

657.00 MHz

663.00 MHz

669.00 MHz

SNR

40.37 dB

38.98 dB

40.37 dB

38.98 dB

38.61 dB

37.64 dB

38.61 dB

38.98 dB

38.61 dB

38.98 dB

38.61 dB

Power Level

0.20 dBmV

-0.40 dBmV

-0.70 dBmV

-1.40 dBmV

-1.90 dBmV

-2.60 dBmV

-3.50 dBmV

-3.80 dBmV

-3.10 dBmV

-2.80 dBmV

-2.20 dBmV

-2.10 dBmV

-2.50 dBmV

-2.20 dBmV

-2.50 dBmV

-1.90 dBmV

-2.30 dBmV

-1.70 dBmV

-1.50 dBmV

-1.60 dBmV

-1.20 dBmV

Modulation

256 QAM

EG · ‎12-03-2019

Further posting here will not fix your issue, unfortunately. You need to get the techs re-involved. 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 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. Good luck with it.

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ableiman · ‎06-25-2020

@tsmccull

Did you ever get your issue resolved? I'm having a very similar issue

I have a very similar sounding problem in Seattle. Techs have been out three times. Swapped modems. Changed all the cables and connectors. Checked connections up and down the street. Checked the upstream and downstream signals looked good. Last guy was here for 2 hours and seemed really competent but he had no clue what might be causing this.

EG · ‎06-25-2020

Dead thread from last year now being closed.

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Internet disconnecting multiple times per day

Internet disconnecting multiple times per day

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