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Constant internet drops.

Frequent Visitor

Constant internet drops.

Constant disconnects to the internet, then not internet for days and now back to constant disconnects to the internet.  

ISP: Comcast Blast Pro
Modem: SB4161
Router: Ubiquiti USG 3P 
Wireless Access Points: Ubiquiti (2x) AP-AC-LR 
Switch: TP-Link 24 port managed swtich (TL-SG1024DE)
Network Controller: Hosted on AWS

 

I spoke with customer service on the phone and they said there was a signal issue or my modem was bad but they would send out a tech.  Tech comes out and says he checked the signal/noise when he pulled in and it's all within spec.  He then proceeded to blame the networking equipment (even though all internal to the network transfers, etc were at gig speeds).  While he was there we bypassed everything, connected straight to the modem and pinging google, etc worked perfectly so 'not a comcast problem'.  Well.... from what I've been reading, modem instability can be caused by fluctuating signals, signal 'leakage' or out of spec signals.  It happened again yesterday and I was lucky enough to remember how to access my modems signal page.  Any help would be much appreciated as I'm at my whits end... is the modem bad? are the signals bad?  All new wiring (crimped by comcast) RG-6Q.  Comes in from the pole, hits one splitter going to the server rack and X1 box, then another splitter at the server rack to Modem / TV / Network Tuner.

 

Right when the internet went out again:

Downstream

Bonding Channel Value

Channel ID

Frequency

513000000 Hz 

Signal to Noise Ratio

37 dB 

Downstream Modulation

QAM256 

Power Level

The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

0 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

17300000 Hz 

Ranging Service ID

n/a 

Symbol Rate

5.120 Msym/sec 

Power Level

55 dBmV 

Upstream Modulation

[2] QPSK
[1] 16QAM
[3] 64QAM
 

Ranging Status

Aborted 

 

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

Total Unerrored Codewords

511698 

Total Correctable Codewords

Total Uncorrectable Codewords

1338 

 

After I’m able to get another signal:

Downstream

Bonding Channel Value

Channel ID

10 

11 

12 

13 

14 

15 

16 

Frequency

543000000 Hz 

549000000 Hz 

555000000 Hz 

561000000 Hz 

567000000 Hz 

573000000 Hz 

579000000 Hz 

585000000 Hz 

Signal to Noise Ratio

37 dB 

37 dB 

37 dB 

36 dB 

37 dB 

37 dB 

38 dB 

36 dB 

Downstream Modulation

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

Power Level

The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

17300000 Hz 

30100000 Hz 

36500000 Hz 

23700000 Hz 

Ranging Service ID

60 

60 

60 

60 

Symbol Rate

5.120 Msym/sec 

5.120 Msym/sec 

5.120 Msym/sec 

5.120 Msym/sec 

Power Level

51 dBmV 

51 dBmV 

51 dBmV 

51 dBmV 

Upstream Modulation

[2] QPSK
[1] 16QAM
[3] 64QAM
 

[2] QPSK
[1] 16QAM
[3] 64QAM
 

[2] QPSK
[1] 16QAM
[3] 64QAM
 

[2] QPSK
[1] 16QAM
[3] 64QAM
 

Ranging Status

Success 

Success 

Success 

Success 

 

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

10 

11 

12 

13 

14 

15 

16 

Total Unerrored Codewords

4206501 

2992456 

3000730 

3009267 

2984289 

2986162 

2988124 

2985945 

Total Correctable Codewords

15 

13 

43 

14 

Total Uncorrectable Codewords

1340 

1439 

1350 

1452 

1461 

1492 

1596 

1499 

 

 

Still having intermittent issues with these results-

Downstream

Bonding Channel Value

Channel ID

Frequency

483000000 Hz 

489000000 Hz 

495000000 Hz 

507000000 Hz 

513000000 Hz 

519000000 Hz 

525000000 Hz 

531000000 Hz 

Signal to Noise Ratio

37 dB 

37 dB 

37 dB 

37 dB 

37 dB 

37 dB 

37 dB 

37 dB 

Downstream Modulation

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

Power Level

The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

-1 dBmV  

-1 dBmV  

-1 dBmV  

-1 dBmV  

-1 dBmV  

-1 dBmV  

0 dBmV  

0 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

17300000 Hz 

30100000 Hz 

36500000 Hz 

23700000 Hz 

Ranging Service ID

60 

60 

60 

60 

Symbol Rate

5.120 Msym/sec 

5.120 Msym/sec 

5.120 Msym/sec 

5.120 Msym/sec 

Power Level

52 dBmV 

54 dBmV 

53 dBmV 

52 dBmV 

Upstream Modulation

[2] QPSK
[1] 16QAM
[3] 64QAM
 

[2] QPSK
[1] 16QAM
[3] 64QAM
 

[2] QPSK
[1] 16QAM
[3] 64QAM
 

[2] QPSK
[1] 16QAM
[3] 64QAM
 

Ranging Status

Success 

Aborted 

Success 

Success 

 

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

Total Unerrored Codewords

10512632 

9306577 

9323103 

9337340 

9283824 

9285391 

9289631 

9288491 

Total Correctable Codewords

224 

372 

292 

734 

139 

267 

180 

144 

Total Uncorrectable Codewords

4943 

5084 

5005 

7730 

4036 

5232 

4169 

4017 

 

 

Expert

Re: Constant internet drops.

Hi @HolgarDK,

Thank you for visiting the forums!

Looks like you have an intermittent upstream issue. This could be caused by a bad modem, but more likely it's a bad wire/connector or splitter someplace. I could also be something on Comcast's end. Can you post your error/event log pls? You might find some useful info here: troubleshooting guide.

 

 

I've asked a Comcast employee to check your modem/node health. You should expect a reply in this thread. 

 

FYI: They owe you a $20 credit for every tech visit after the first for the same problem.You can also get a credit for your service from the time you first reported the issue until it is resolved.




I am not a Comcast employee, just a moderator. Pls observe Wheaton's Law.
Frequent Visitor

Re: Constant internet drops.

This is the latest logs... which I believe do not capture the same time period as the singals from last night (shocker, too many issues to log in the last 12 hours!)

 

Time Priority Code Message
Jun 27 2018 05:26:52 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jun 27 2018 00:42:16 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC
Jun 27 2018 00:41:36 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jun 27 2018 00:41:36 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jun 27 2018 00:30:21 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jun 26 2018 23:07:33 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;
Jan 01 1970 00:07:49 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:07:25 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jan 01 1970 00:07:17 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:07:06 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jan 01 1970 00:07:00 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:06:35 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jan 01 1970 00:06:33 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:06:07 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jan 01 1970 00:06:01 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:05:47 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jan 01 1970 00:05:44 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:05:29 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Jan 01 1970 00:05:23 3-Critical R02.0 No Ranging Response received - T3 time-out;
Jan 01 1970 00:05:08 3-Critical R07.0 Unicast Ranging Received Abort Response - initializing MAC;
Frequent Visitor

Re: Constant internet drops.

Another sample of signal levels-

Downstream Bonding Channel Value
Channel ID
Frequency 483000000 Hz  489000000 Hz  495000000 Hz  507000000 Hz  513000000 Hz  519000000 Hz  525000000 Hz  531000000 Hz 
Signal to Noise Ratio 37 dB  37 dB  37 dB  37 dB  37 dB  37 dB  37 dB  37 dB 
Downstream Modulation QAM256  QAM256  QAM256  QAM256  QAM256  QAM256  QAM256  QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
-1 dBmV   -1 dBmV   -1 dBmV   -1 dBmV   -1 dBmV   -1 dBmV   -1 dBmV   -1 dBmV  

 

Upstream Bonding Channel Value
Channel ID
Frequency 17300000 Hz  30100000 Hz  36500000 Hz  23700000 Hz 
Ranging Service ID 60  60  60  60 
Symbol Rate 5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 49 dBmV  51 dBmV  51 dBmV  50 dBmV 
Upstream Modulation [2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
Ranging Status Success  Success  Success  Success 

 

Signal Stats (Codewords) Bonding Channel Value
Channel ID
Total Unerrored Codewords 2018587612  2018171374  2018196312  2018214064  2018148637  2018150670  2018151392  2018155846 
Total Correctable Codewords 2155  2285  2429  1802  1974  1697  1667  1499 
Total Uncorrectable Codewords 8335  6263  6335  5548  5304  6185  6082  4433
Official Employee

Re: Constant internet drops.

Hello HolgarDK. Thank you for providing your modem logs. I can assist with further troubleshooting your intermittent connectivity issues. I'd like to start with polling the CMTS for real-time and historical RF signal reports from your modem. I can also check your local Node/Plant for any degradation or error reports. Please send me a private message and include your full name and account primary phone number so I can access your equipment.

Frequent Visitor

Re: Constant internet drops.

Thank you.

 

I have sent you a PM with the requested info.

Frequent Visitor

Re: Constant internet drops.

As the problem started out of nowhere (no new additional equipment, wiring, etc), I'm starting to work on scenarios and remove any potential problems within my control (not a Comcast issue due to new people moving in nearby and some switch being messed up).  Only way I know to test that is install the modem on the drop line going into the house, get signal levels as a baseline.  Reinstall the modem in the server room, take signal levels... observe the drop.  This does not account for fluctuating signals (which I'm experiencing).

 

If the signal is drastically different, check the following:

  1. Wiring - I know my coax is good as I ripped out all the old coax and reran it with RG6Q with Comcast crimping the ends correctly (non-push/screw on).  Nothing has changed in the past few years.  The issue could be with the line from the street (pole) to the house and the outside connector?  It is Seattle rain after all...
  2. Splitters I'm told do go bad.  I'm going to replace the splitters (Pole into the house --> 2way --> to the server closet --> 3-way --> modem).  I know the ideal would be not to have two splitters prior to the modem but it can't be avoided without either moving the modem (running cat6) or home running the pole-->server closet (running coax).  Are these the correct splitters to buy?
    1. https://www.amazon.com/BAMF-2-Way-Splitter-Bi-Directional-5-2300MHz/dp/B0113JAN8K/
    2. https://www.amazon.com/BAMF-3-Way-Splitter-Bi-Directional-5-2300MHz/dp/B017T9KKHW/
  3. Modems do go bad/overheat... I'm thinking about adding a fan to the case of the SB6141 to actively cool it.  The ambient in the server closet is 70, so it shouldn't be needed but who knows.  Last resort is to put in a new modem (https://www.amazon.com/gp/product/B0723599RQ/)
Frequent Visitor

Re: Constant internet drops.


@HolgarDK
  1. Modems do go bad/overheat... I'm thinking about adding a fan to the case of the SB6141 to actively cool it.  The ambient in the server closet is 70, so it shouldn't be needed but who knows.  Last resort is to put in a new modem (https://www.amazon.com/gp/product/B0723599RQ/)

I had wondered exactly the same thing because I've been struggling with packet loss, even after replacing my SB6141 months ago with an SB6183.  The new modem shaved a few ms off the ping RTT.  I noticed that the cable connection was extremely hot and I thought that the heat might affect the RF/IF frontend, so I cut a hole in the case and superglued a small 12V fan to the case.  The 6183 has the SOC on the other side of the board to the 6141 and it's the SOC that dissipates all the heat.

 

The modem runs cool now, but its had no effect on the error rate ar my packet loss.  As far as I can tell, there's no correlation to the temperature, but perhaps the damage has already been done and a new modem with a fan will improve the longevity.

New Poster

Re: Constant internet drops.

The SB6141, SB6190 and the SB6183 both use variants of the Intel Puma chip... which has been proven to contain a defect and is prone to all kinds of cable problems. There is actually a class action lawsuit going on related to the same: https://www.theregister.co.uk/2017/04/11/intel_puma_6_arris/

 

I had no end of problems with Arris, and ultimately went with a Netgear CM1000. Uses the Broadcom chip and DOCSIS 3.1 to help future proof it a bit. Save yourself some headache and do something simila. Puma = BAD.

Diamond Problem Solver

Re: Constant internet drops.


@kensloth wrote:

The SB6141, SB6190 and the SB6183 both use variants of the Intel Puma chip...


FWIW, the SB6183 also uses a Broadcom chipset that is NOT subject to the same problems as the Puma 6,7.

New Poster

Re: Constant internet drops.

Ah, you are correct. My mistake.

 

Thanks

Diamond Problem Solver

Re: Constant internet drops.

No worries ! Smiley Happy