U

Visitor

 • 

12 Messages

Wed, Apr 21, 2021 3:23 AM

Disconnects and internet speed drops require restarting modem all the time

We recently switched to an internet only service, and ever since switching, we’ve been having issues exactly the same as this post:

https://forums.xfinity.com/conversations/your-home-network/intermittent-disconnects-constant-modem-restarting-to-maintain-service-after-upgrading/602daf24c5375f08cd02463f

The event logs for the modem (I have the exact same model as mentioned in that post - the SB6190) contain the same exact error messages. Internet speeds will drop out randomly throughout the day, making it difficult to work from home. Restarting the modem temporarily fixes the issue and returns my internet speeds back to normal. The drops also appear to cause my Flex boxes to crash, I am assuming. Strangely, when we had cable at the house with a different speed internet (but the same modem), we didn’t run into any of these issues, but since switching accounts and into the internet only plan, they occur daily.

Someone on the post I linked to said Xfinity may be able to help. Thank you so much in advance for any guidance/help better understanding the issue.

This post was escalated on April 21, 2021 by EG

Responses

EG

Expert

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86.7K Messages

1 m ago

(edited)

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!tick

Visitor

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12 Messages

Hi, thank you. Yes, that's a great post. I had read through it and I've tried following all the troubleshooting information - I didn't see anything obvious with the cabling and other equipment. It appears to be something with the modem vs. the router. I've posted the logs and status from my SB6190 on this post.

Visitor

 • 

12 Messages

1 m ago

I am still experiencing this frequently. Here is the status from the modem:

Procedure

Status

Comment

Acquire Downstream Channel

Locked

Connectivity State

OK

Operational

Boot State

OK

Operational

Configuration File

OK

Security

Enabled

BPI+

DOCSIS Network Access Enabled

Allowed

Downstream Bonded Channels

Channel

Lock Status

Modulation

Channel ID

Frequency

Power

SNR

Corrected

Uncorrectables

1

Locked

256QAM

13

489.00 MHz

2.30 dBmV

30.82 dB

1244056

460014

2

Locked

256QAM

14

507.00 MHz

2.40 dBmV

40.37 dB

0

0

3

Locked

256QAM

15

513.00 MHz

1.70 dBmV

40.37 dB

0

0

4

Locked

256QAM

16

519.00 MHz

1.60 dBmV

38.98 dB

0

0

5

Locked

256QAM

17

525.00 MHz

1.70 dBmV

38.61 dB

12

0

6

Locked

256QAM

18

531.00 MHz

2.10 dBmV

40.37 dB

15

0

7

Locked

256QAM

19

537.00 MHz

1.80 dBmV

40.95 dB

10

0

8

Locked

256QAM

20

543.00 MHz

1.50 dBmV

40.37 dB

0

0

9

Locked

256QAM

21

549.00 MHz

1.40 dBmV

37.36 dB

0

0

10

Not Locked

----

22

555.00 MHz

----

----

----

----

11

Not Locked

----

23

561.00 MHz

----

----

----

----

12

Not Locked

----

24

567.00 MHz

----

----

----

----

13

Not Locked

----

25

573.00 MHz

----

----

----

----

14

Locked

256QAM

26

579.00 MHz

0.80 dBmV

33.96 dB

537230

834871

15

Not Locked

----

27

585.00 MHz

----

----

----

----

16

Locked

256QAM

28

591.00 MHz

0.40 dBmV

29.71 dB

5306068

613060

17

Locked

256QAM

29

597.00 MHz

-0.40 dBmV

37.36 dB

0

0

18

Locked

256QAM

30

603.00 MHz

-0.10 dBmV

38.98 dB

4

0

19

Locked

256QAM

31

609.00 MHz

0.20 dBmV

40.37 dB

0

0

20

Locked

256QAM

32

615.00 MHz

0.00 dBmV

40.37 dB

0

0

21

Locked

256QAM

34

621.00 MHz

0.40 dBmV

40.37 dB

7

0

22

Locked

256QAM

35

627.00 MHz

0.00 dBmV

38.61 dB

3

0

23

Locked

256QAM

36

633.00 MHz

-0.40 dBmV

37.64 dB

0

0

24

Locked

256QAM

37

639.00 MHz

0.00 dBmV

37.09 dB

0

0

25

Locked

256QAM

38

645.00 MHz

0.10 dBmV

39.90 dB

7

0

26

Locked

256QAM

39

651.00 MHz

0.00 dBmV

39.90 dB

16

0

27

Locked

256QAM

40

657.00 MHz

-0.70 dBmV

39.50 dB

11

0

28

Locked

256QAM

41

663.00 MHz

-0.40 dBmV

39.90 dB

0

0

29

Locked

256QAM

42

669.00 MHz

-0.40 dBmV

39.90 dB

0

0

30

Locked

256QAM

43

675.00 MHz

-0.30 dBmV

39.90 dB

0

0

31

Locked

256QAM

44

681.00 MHz

-0.10 dBmV

39.90 dB

0

0

32

Locked

256QAM

45

687.00 MHz

-0.60 dBmV

39.90 dB

0

0

Upstream Bonded Channels

Channel

Lock Status

US Channel Type

Channel ID

Symbol Rate

Frequency

Power

1

Locked

ATDMA

26

5120 kSym/s

30.10 MHz

38.25 dBmV

2

Locked

ATDMA

27

5120 kSym/s

23.70 MHz

37.25 dBmV

3

Locked

ATDMA

25

5120 kSym/s

36.50 MHz

39.25 dBmV

Visitor

 • 

12 Messages

1 m ago

And here is event log. Does anything pop out to anyone?

Wed Apr 21 12:24:21 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:30 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:30 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:45 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:45 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:46 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:47 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:53 2021

3

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:53 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:58 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:24:59 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:02 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:02 2021

3

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:02 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:02 2021

3

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:04 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:19 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:20 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:24 2021

5

Lost MDD Timeout;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

Wed Apr 21 12:25:25 2021

5

RCS Partial Service;CM-MAC=2c:7e:81:2b:a5:bf;CMTS-MAC=00:01:5c:8f:2c:68;CM-QOS=1.1;CM-VER=3.0;

EG

Expert

 • 

86.7K Messages

1 m ago

The signal stats are o/k but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) /  an upstream channel-return path impairment 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 will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. 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!tick

Visitor

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12 Messages

1 m ago

Thank you so much for the help! I have been having an especially difficult time the past two days with drop outs and slowness, so the additional help is much appreciated.

EG

Expert

 • 

86.7K Messages

Quite welcome !

______________________

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!tick

Official Employee

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178 Messages

Hello and thank you for taking the time to post to our Xfinity Forums, I'm truly sorry to hear that you are experiencing these drops in connection and speed concerns. I would love the opportunity to look into everything on our end. Please send us a private message with your name and service address to Xfinity Support by clicking the chat icon at the top right of the page.

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!tick

Visitor

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12 Messages

Thank you! I've sent a message in the private messages with my information.

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