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Internet connectivity issues w/ no resolution after 2 technician visits

New Poster

Internet connectivity issues w/ no resolution after 2 technician visits

Hello all,

 

I need some help and am not sure how to get Xfinity to resolve this issue. Ever since I moved into my current place (December 17, 2018), I’ve had internet connectivity problems. The connection totally drops many times every day, and it happens at any time, so there’s no discernible pattern. I’m usually able to get it going again by unplugging the coax and doing 1 to 3 full modem resets, though sometimes it doesn’t work and the internet will be out for a half hour or so. Also, the upstream light on the modem often blinks green.

 

I’m using the same modem that I used at my previous place (Netgear CM500-100NAS, purchased one year ago). I’ve never had any issues before I moved into my new place, and the issues were nearly immediate here.

 

I’ve now had two technicians come out, but they both said that the lines and signal were fine, and that it must be a bad modem. All things considered, I don’t think it’s my modem going bad. Here are the stats from the Netgear dashboard about an hour after resetting and just before yet another dropped connection:

 

Startup Procedure

Procedure

Status

Comment

Acquire Downstream Channel

645000000 Hz

Locked

Connectivity State

OK

Operational

Boot State

OK

Operational

Security

Enabled

BPI+

IP Provisioning Mode

Honor MDD

honorMdd(4)

 

Downstream Bonded Channels

Channel

Lock Status

Modulation

Channel ID

Frequency

Power

SNR

Correctables

Uncorrectables

1

Locked

QAM256

17

645000000 Hz

4.4 dBmV

40.3 dB

578

29

2

Locked

QAM256

31

729000000 Hz

7.7 dBmV

41.6 dB

7

26

3

Locked

QAM256

18

651000000 Hz

4.4 dBmV

40.4 dB

369

15

4

Locked

QAM256

19

657000000 Hz

4.9 dBmV

40.6 dB

193

27

5

Locked

QAM256

20

663000000 Hz

5.2 dBmV

40.9 dB

194

34

6

Locked

QAM256

21

669000000 Hz

6.2 dBmV

41.4 dB

47

42

7

Locked

QAM256

22

675000000 Hz

6.6 dBmV

41 dB

51

18

8

Locked

QAM256

23

681000000 Hz

7 dBmV

41.7 dB

42

35

9

Locked

QAM256

24

687000000 Hz

7.5 dBmV

42 dB

15

26

10

Locked

QAM256

25

693000000 Hz

7.7 dBmV

42 dB

28

58

11

Locked

QAM256

26

699000000 Hz

7.5 dBmV

42 dB

12

27

12

Locked

QAM256

27

705000000 Hz

7.5 dBmV

42 dB

35

25

13

Locked

QAM256

28

711000000 Hz

7.6 dBmV

41.9 dB

28

32

14

Locked

QAM256

29

717000000 Hz

7.2 dBmV

41.6 dB

26

26

15

Locked

QAM256

30

723000000 Hz

7.6 dBmV

41.6 dB

27

30

16

Locked

QAM256

16

639000000 Hz

4 dBmV

40.2 dB

927

71

 

Upstream Bonded Channels (Partial Service)

Channel

Lock Status

US Channel Type

Channel ID

Symbol Rate

Frequency

Power

1

Locked

ATDMA

1

5120 Ksym/sec

36500000 Hz

48.5 dBmV

2

Locked

ATDMA

2

5120 Ksym/sec

30100000 Hz

48.5 dBmV

3

Locked

ATDMA

3

5120 Ksym/sec

23700000 Hz

49 dBmV

4

Locked

ATDMA

4

5120 Ksym/sec

17300000 Hz

49 dBmV

 

Current System Time:Sun Feb 10 18:10:36 2019

 

Time

Priority

Description

2019-2-9, 17:14:11

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:22

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:29

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:51

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:21

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2019-2-9, 23:48:13

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 09:52:20

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 09:52:40

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

2019-2-10, 09:52:51

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

2019-2-10, 09:55:12

Critical (3)

Resetting the cable modem due to docsDevResetNow

1970-1-1, 00:00:21

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:27

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

2019-2-10, 10:08:56

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:15:45

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:15:49

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:16:17

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:16:19

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:16:50

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:18:44

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

2019-2-10, 11:19:10

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

2019-2-10, 11:20:10

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 11:31:56

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 12:46:05

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 12:46:09

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 12:46:37

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 12:47:00

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 12:48:55

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

2019-2-10, 12:49:09

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:22

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:27

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:51

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:21

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:33

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

2019-2-10, 15:31:43

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 18:10:24

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 18:10:28

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 18:10:56

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 18:10:56

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 18:11:23

Critical (3)

Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

2019-2-10, 18:11:29

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:b9:8a:23:b0:90;CMTS-MAC=00:a3:d1:5c:58:ec;CM-QOS=1.1;CM-VER=3.0;

 

Here are the stats from just after resetting just now:

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 621000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 13 621000000 Hz 4.6 dBmV 40.3 dB 342 49
2 Locked QAM256 1 549000000 Hz 6.3 dBmV 41.6 dB 0 0
3 Locked QAM256 2 555000000 Hz 6.3 dBmV 41.5 dB 0 0
4 Locked QAM256 3 561000000 Hz 6.4 dBmV 41.6 dB 0 0
5 Locked QAM256 4 567000000 Hz 6.2 dBmV 41.6 dB 0 0
6 Locked QAM256 5 573000000 Hz 6.1 dBmV 41.6 dB 0 0
7 Locked QAM256 6 579000000 Hz 5.8 dBmV 41.2 dB 0 0
8 Locked QAM256 7 585000000 Hz 6 dBmV 41.4 dB 0 0
9 Locked QAM256 8 591000000 Hz 6.1 dBmV 41.3 dB 0 0
10 Locked QAM256 9 597000000 Hz 6.1 dBmV 41.1 dB 4 0
11 Locked QAM256 10 603000000 Hz 6.1 dBmV 41.1 dB 69 23
12 Locked QAM256 11 609000000 Hz 5.7 dBmV 40.8 dB 150 0
13 Locked QAM256 12 615000000 Hz 5.2 dBmV 40.4 dB 204 0
14 Locked QAM256 14 627000000 Hz 4.9 dBmV 40.3 dB 433 259
15 Locked QAM256 15 633000000 Hz 4.5 dBmV 40.2 dB 306 713
16 Locked QAM256 16 639000000 Hz 4.1 dBmV 40 dB 314 806
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 36500000 Hz 48.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 30100000 Hz 48.5 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 23700000 Hz 48.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 17300000 Hz 48.5 dBmV
 

Current System Time:Sun Feb 10 18:20:14 2019

 

Any help would be greatly appreciated!

Expert

Re: Internet connectivity issues w/ no resolution after 2 technician visits

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

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




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!
New Poster

Re: Internet connectivity issues w/ no resolution after 2 technician visits

My levels are posted above. Please let me know what you think.

Expert

Re: Internet connectivity issues w/ no resolution after 2 technician visits

The upstream power is on the high side (more so in pic number 1) and they may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, and speed and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there 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 types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

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.




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!
New Poster

Re: Internet connectivity issues w/ no resolution after 2 technician visits

Thanks for your reply. I finally got a tech out here (3rd one) that actually tried to troubleshoot it, and he ended up replacing the drop and removing a splitter. Here are the levels now:

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 669000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 21 669000000 Hz 11.3 dBmV 40.7 dB 0 0
2 Locked QAM256 16 639000000 Hz 10.5 dBmV 40.3 dB 0 0
3 Locked QAM256 18 651000000 Hz 10.8 dBmV 40.5 dB 0 0
4 Locked QAM256 19 657000000 Hz 10.6 dBmV 40.4 dB 0 0
5 Locked QAM256 20 663000000 Hz 11.1 dBmV 40.6 dB 0 0
6 Locked QAM256 17 645000000 Hz 10.8 dBmV 40.5 dB 0 0
7 Locked QAM256 22 675000000 Hz 11.3 dBmV 40.3 dB 0 0
8 Locked QAM256 23 681000000 Hz 11.6 dBmV 40.9 dB 0 0
9 Locked QAM256 24 687000000 Hz 11.7 dBmV 41 dB 0 0
10 Locked QAM256 25 693000000 Hz 11.7 dBmV 41 dB 0 0
11 Locked QAM256 26 699000000 Hz 11.6 dBmV 41 dB 0 0
12 Locked QAM256 27 705000000 Hz 12 dBmV 41.1 dB 0 0
13 Locked QAM256 28 711000000 Hz 12 dBmV 41.1 dB 0 0
14 Locked QAM256 29 717000000 Hz 11.7 dBmV 40.9 dB 0 0
15 Locked QAM256 30 723000000 Hz 12 dBmV 40.9 dB 0 0
16 Locked QAM256 31 729000000 Hz 12.1 dBmV 40.9 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 36500000 Hz 43.8 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 30100000 Hz 43.8 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 23700000 Hz 43.8 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 17300000 Hz 43.8 dBmV
 
Current System Time:Wed Feb 13 17:13:36 2019

 

 

Hopefully this fixes it for good!