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Dr_Sagui
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Sunday, February 6th, 2022 1:20 AM

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Internet has been spotty recently, even Tech couldn't fix it.

For the past month or so, our internet has been working well 90% of the time, but during mornings and evenings in particular, it gets spotty. By spotty, I mean that within an hour, the internet will drop 4 or 5 times. After a couple calls with Xfinity, we had a Technician come out to look at it. He found no issues, but replaced the line from the pole of the house. However the issues persist.

This is happening on two separate cable modems, the one I'm currently using is an ARRIS SB8200. The line goes directly from the pole into the modem, no splitters, wall socket connections, etc.

I managed to capture the logs for one of these outages and posted them below, along with a typical status during times that the internet works.

02/05/2022 20:14 2436694066 6 "Honoring MDD; IP provisioning mode = IPv6"
02/05/2022 20:14 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:14 82000400 3 "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:14 84020300 5 "MDD message timeout;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:14 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:14 82000100 3 "No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:14 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000100 3 "No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84020300 5 "MDD message timeout;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000400 3 "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000100 3 "No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000100 3 "No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84020300 5 "MDD message timeout;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000400 3 "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000100 3 "No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84020300 5 "MDD message timeout;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000100 3 "No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 82000400 3 "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84020300 5 "MDD message timeout;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
02/05/2022 20:13 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;"
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
37 Locked QAM256 675000000 Hz -1.3 dBmV 38.5 dB 529705 542787
9 Locked QAM256 507000000 Hz -11.6 dBmV 32.5 dB 7401199 5856583
10 Locked QAM256 513000000 Hz -12.7 dBmV 31.1 dB 12259779 7251791
11 Locked QAM256 519000000 Hz -14.2 dBmV 30.0 dB 8065017 3393498
12 Locked QAM256 525000000 Hz -15.2 dBmV 28.7 dB 9482468 6272968
13 Locked QAM256 531000000 Hz -16.4 dBmV 27.7 dB 6106307 3303222
14 Locked QAM256 537000000 Hz -17.2 dBmV 27.5 dB 5429475 3525884
15 Locked QAM256 543000000 Hz -17.2 dBmV 27.9 dB 5471665 4487683
16 Locked QAM256 549000000 Hz -16.7 dBmV 29.0 dB 6145102 6211239
17 Locked QAM256 555000000 Hz -15.4 dBmV 29.5 dB 2485851 2304311
18 Locked QAM256 561000000 Hz -14.0 dBmV 30.0 dB 5016782 4252818
19 Locked QAM256 567000000 Hz -12.5 dBmV 31.2 dB 4105145 3404995
20 Locked QAM256 573000000 Hz -11.4 dBmV 32.1 dB 3143167 2463860
21 Locked QAM256 579000000 Hz -10.0 dBmV 32.5 dB 1454325 2218996
22 Locked QAM256 585000000 Hz -9.2 dBmV 32.8 dB 1783051 1723705
23 Locked QAM256 591000000 Hz -8.1 dBmV 32.9 dB 1521195 1433430
24 Locked QAM256 597000000 Hz -7.3 dBmV 35.1 dB 1224411 1240047
25 Locked QAM256 603000000 Hz -6.4 dBmV 35.5 dB 1186472 1129915
26 Locked QAM256 609000000 Hz -6.2 dBmV 34.6 dB 912510 1018451
27 Locked QAM256 615000000 Hz -5.7 dBmV 34.7 dB 867142 945954
28 Locked QAM256 621000000 Hz -5.1 dBmV 35.7 dB 737387 873320
29 Locked QAM256 627000000 Hz -4.7 dBmV 36.3 dB 663696 792415
30 Locked QAM256 633000000 Hz -3.9 dBmV 35.4 dB 558889 728489
31 Locked QAM256 639000000 Hz -3.7 dBmV 35.9 dB 436483 645218
32 Locked QAM256 645000000 Hz -3.0 dBmV 37.0 dB 372114 582073
33 Locked QAM256 651000000 Hz -2.8 dBmV 36.8 dB 819862 1492108
34 Locked QAM256 657000000 Hz -2.1 dBmV 36.7 dB 1288906 1443263
35 Locked QAM256 663000000 Hz -1.8 dBmV 36.9 dB 1080937 1239749
36 Locked QAM256 669000000 Hz -1.3 dBmV 37.5 dB 1362621 1628520
38 Locked QAM256 681000000 Hz -0.7 dBmV 37.1 dB 2071078 3013490
39 Locked QAM256 687000000 Hz -0.4 dBmV 37.5 dB 1363574 1736947
40 Locked QAM256 693000000 Hz 0.2 dBmV 37.5 dB 1567949 1496615
159 Locked Other 702000000 Hz 2.1 dBmV 34.2 dB 159769014 10453

Question

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Updated 

3 years ago

 • Edited

2.4K

3

Accepted Solution

EG

Expert

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110K Messages

3 years ago

@Dr_Sagui 

The downstream power as well as the SNR is too low / out of spec on many of the downstream channels. It looks like you have a severe case of what is called *reverse cable tilt* going on here. 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 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, 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, 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 it's best to book a tech visit to investigate and correct this one.


Good luck with it !

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Dr_Sagui

Visitor

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3 Messages

@EG​

I greatly appreciate the feedback. The symptoms you are describing are EXACTLY what I am seeing.

Unfortunately, all of the remedies you suggested don't apply: the line goes from the pole directly through a hole in the wall into my cable modem, so no splitters, extensions, cables, etc. Also, said cable from the pole to the modem was replaced by a technician 5 days ago (the data I posted is from two days after the cable was switched out), so it appears to be an issue further upstream.

I will take it up with customer service as the person above you suggested. Again, thanks so much for your input!

3 years ago

0

XfinityArmand

Official Employee

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2.1K Messages

We are so glad to take a closer look at this for you @Dr_Sagui.  You have reached out to the right team and we can do some troubleshooting on our end to get this resolved for you.  Please feel free to shoot us a private message so that we can get started on this for you.  

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

3 years ago

0

XfinityArmand

Official Employee

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2.1K Messages

@Dr_Sagui to send a "direct message" / "private message" message to Xfinity Support:

 • Click "Sign In" if necessary

 • Click the "Direct Message" icon or https://comca.st/3oAiQzP 

 • Click the "New message" (pencil and paper) icon

 • The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there

 •  - As you are typing a drop-down list appears. Select "Xfinity Support" from that list

 •  - An "Xfinity Support" graphic replaces the "To:" line

 • Type your message in the text area near the bottom of the window

 • Press Enter to send it

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

3 years ago

0

EG

Expert

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110K Messages

@Dr_Sagui​ 

My pleasure ! This can't be fixed remotely. You need *boots on the ground*. Please post back here with how things turn out. Good luck !

P.S. 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.

(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? Please mark an Accepted Answer!tick
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? Please mark an Accepted Answer!tick

3 years ago

0

Yohan17

Visitor

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3 Messages

Hello,

I have a very similar situation. "Random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels."

I just moved from an apartment to a new house. I have been having connectivity issues ever since the move, and my setup that I have been using for 2 years has not changed. An Xfinity rep came out to check the cables outside and he said everything looked good. After numerous calls with Netgear (R6700v2), Motorola (MB7420) and Xfinity, this has not been resolved for the past week. I work from home, so this has taken a pretty big toll on my day-to-day. Below is my log:

Time   Priority   Description 
Time Not Established  Critical (3)  No Ranging Response received - T3 time-out;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=XX:XX:XX:XX:XX:XX;CM-QOS=1.0;CM-VER=3.0; 
Time Not Established  Notice (6)  Honoring MDD; IP provisioning mode = IPv6 

  Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
1 Locked QAM256 29 573.0 9.1 39.8 9 0
2 Locked QAM256 30 579.0 9.1 39.7 9 0
3 Locked QAM256 31 585.0 9.9 40.1 5 0
4 Locked QAM256 32 591.0 9.6 40.1 8 0
5 Locked QAM256 33 597.0 9.9 40.1 7 0
6 Locked QAM256 34 603.0 10.8 40.3 4 0
7 Locked QAM256 35 609.0 10.5 40.2 3 0
8 Locked QAM256 36 615.0 10.6 40.1 11 0
9 Locked QAM256 37 621.0 11.1 40.3 7 0
10 Locked QAM256 38 627.0 10.9 40.2 8 0
11 Locked QAM256 39 633.0 11.6 40.2 8 0
12 Locked QAM256 40 639.0 11.9 39.8 4 0
13 Locked QAM256 41 645.0 11.5 40.1 12 0
14 Locked QAM256 42 651.0 11.9 40.1 11 0
15 Locked QAM256 43 657.0 12.3 40.3 9 0
16 Locked QAM256 44 663.0 12.4 40.4 12 0
Total             127 0

hannel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
1 Locked ATDMA 3 5120 29.2 40.2
2 Locked ATDMA 1 5120 16.4 40.2
3 Locked ATDMA 2 5120 22.8 40.2
4 Locked ATDMA 4 5120 35.6 40.2

I am noticing poor signal numbers but would appreciate some input on what to say to the Xfinity Technician the next time they come. 

Whether we need an amplifier, splitter, etc... If this does not work out with the next technician, I'll be performing the alterations myself. Thanks in advance

(edited)

3 years ago

0

XfinityAmandaB

Official Employee

 • 

2.1K Messages

3 years ago

Hello, there @Dr_Sagui thank you so much for your post about your intermittent connection issues. I definitely know how important it is to have the connection you need when you need it! I would be happy to help take a closer look at your connection on my end if you would like.

If you could send our team a private message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into your connection for you!

 

Here are the detailed steps to direct message us: • Click "Sign In" if necessary • Click the "Peer to peer chat" icon (upper right corner of this page) • Click the "New message" (pencil and paper) icon • Type "Xfinity Support" in the to line and select "Xfinity Support" from the drop-down list • Type your message in the text area near the bottom of the window • Press Enter to send your message

 

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Dr_Sagui

Visitor

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3 Messages

3 years ago

@XfinityArmand I have started my DM with the Support Team. Hopefully we will be able to straighten this out.

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