3 Messages
Frequent Connection Drops and Uncorrected Errors on 3/33 Channels (Suspected Noise on Line)
We are experiencing frequent "blips" where the internet drops out at our condo and comes back online after a brief 1-5 minute period.
Previously, we had similar problems and a tech was able to trace the line and determine that someone had fitted a dampener on our connection to the main junction box in the condo building. At that time, he confirmed that our coax layout (all cables, connections, and in-line splitters) were delivering the expected signal to the modem but the presence of the dampener was causing issues due to the artificial ceiling on the signal frequency. For a time afterwards, the connection worked flawlessly. However, for the past month (or maybe a little more), we are again experiencing issues staying connected consistently and this is confirmed in the modem event logs.
Specifically, we see large numbers of uncorrected errors on 3 channels (including the OFDM PLC channel):
Channel | Lock Status | Modulation | Channel ID | Freq. (MHz) | Pwr (dBmV) | SNR (dB) | Corrected | Uncorrected |
1 | Locked | QAM256 | 20 | 567.0 | 4.8 | 43.4 | 15 | 0 |
2 | Locked | QAM256 | 1 | 453.0 | 6.5 | 45.1 | 16 | 0 |
3 | Locked | QAM256 | 2 | 459.0 | 6.5 | 45.0 | 690 | 2593 |
4 | Locked | QAM256 | 3 | 465.0 | 6.4 | 44.8 | 1058 | 2821 |
5 | Locked | QAM256 | 4 | 471.0 | 6.2 | 44.7 | 31 | 0 |
6 | Locked | QAM256 | 5 | 477.0 | 6.3 | 44.8 | 20 | 0 |
7 | Locked | QAM256 | 6 | 483.0 | 6.4 | 44.9 | 1 | 0 |
8 | Locked | QAM256 | 7 | 489.0 | 6.7 | 44.8 | 11 | 0 |
9 | Locked | QAM256 | 8 | 495.0 | 6.5 | 44.9 | 27 | 0 |
10 | Locked | QAM256 | 9 | 501.0 | 6.6 | 44.8 | 26 | 0 |
11 | Locked | QAM256 | 10 | 507.0 | 6.3 | 44.8 | 11 | 0 |
12 | Locked | QAM256 | 11 | 513.0 | 5.8 | 44.3 | 1 | 0 |
13 | Locked | QAM256 | 12 | 519.0 | 5.7 | 44.4 | 11 | 0 |
14 | Locked | QAM256 | 13 | 525.0 | 5.6 | 44.2 | 16 | 0 |
15 | Locked | QAM256 | 14 | 531.0 | 5.1 | 44.0 | 12 | 0 |
16 | Locked | QAM256 | 15 | 537.0 | 4.7 | 43.5 | 2 | 0 |
17 | Locked | QAM256 | 16 | 543.0 | 5.2 | 44.0 | 4 | 0 |
18 | Locked | QAM256 | 17 | 549.0 | 4.9 | 43.6 | 2 | 0 |
19 | Locked | QAM256 | 18 | 555.0 | 5.2 | 43.6 | 1 | 0 |
20 | Locked | QAM256 | 19 | 561.0 | 5.3 | 43.8 | 13 | 0 |
21 | Locked | QAM256 | 21 | 573.0 | 4.6 | 43.4 | 19 | 0 |
22 | Locked | QAM256 | 22 | 579.0 | 4.2 | 43.0 | 7 | 0 |
23 | Locked | QAM256 | 23 | 585.0 | 4.4 | 43.1 | 6 | 0 |
24 | Locked | QAM256 | 24 | 591.0 | 3.9 | 42.9 | 20 | 0 |
25 | Locked | QAM256 | 25 | 597.0 | 4.4 | 43.0 | 16 | 0 |
26 | Locked | QAM256 | 26 | 603.0 | 3.9 | 42.7 | 26 | 0 |
27 | Locked | QAM256 | 27 | 609.0 | 4.3 | 43.0 | 17 | 0 |
28 | Locked | QAM256 | 28 | 615.0 | 3.7 | 42.6 | 10 | 0 |
29 | Locked | QAM256 | 29 | 621.0 | 3.9 | 42.7 | 3 | 0 |
30 | Locked | QAM256 | 30 | 627.0 | 3.9 | 42.6 | 3 | 0 |
31 | Locked | QAM256 | 31 | 633.0 | 3.6 | 42.5 | 1 | 0 |
32 | Locked | QAM256 | 32 | 639.0 | 4.0 | 42.8 | 65 | 0 |
33 | Locked | OFDM PLC | 193 | 957.0 | -0.7 | 38.9 | -1740062231 | 1709408452 |
Additionally, we see a number of errors that seem to indicate the OFDM PLC channel is operating outside of the expected bounds. For example, here is the event log for a recent failure on the OFDM PLC channel:
Time | Priority | Description |
07:47:20 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1 2 3.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
07:47:22 Tue Jun 4 2024 |
Warning (5) | MDD message timeout;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
07:47:23 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 21; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
07:47:46 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 4; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
07:49:02 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 22; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
07:49:02 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1 2 3.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
07:49:51 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 23; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
Similarly, here is a recent event log for a failure on Channel ID 2:
Time | Priority | Description |
09:28:54 Tue Jun 4 2024 |
Notice (6) | CM-STATUS message sent. Event Type Code: 5; Chan ID: 2 3; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
I also see a number of other warnings and errors unrelated to any particular channels:
Time | Priority | Description |
01:14:04 Thu Jun 6 2024 |
Warning (5) | MDD message timeout;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:14:47 Thu Jun 6 2024 |
Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:14:55 Thu Jun 6 2024 |
Critical (3) | No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:14:56 Thu Jun 6 2024 |
Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:14:57 Thu Jun 6 2024 |
Critical (3) | No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:14:57 Thu Jun 6 2024 |
Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:15:48 Thu Jun 6 2024 |
Warning (5) | Lost MDD Timeout;CM-MAC=XXXX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
01:18:31 Thu Jun 6 2024 |
Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XXXX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
01:19:09 Thu Jun 6 2024 |
Warning (5) | Lost MDD Timeout;CM-MAC=XXXX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
01:19:18 Thu Jun 6 2024 |
Critical (3) | UCD invalid or channel unusable;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:20:03 Thu Jun 6 2024 |
Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:20:13 Thu Jun 6 2024 |
Notice (6) | Honoring MDD; IP provisioning mode = IPv6 |
01:20:50 Thu Jun 6 2024 |
Critical (3) | DHCP failed - DHCP Solicit sent, No DHCP Advertise received;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:23:34 Thu Jun 6 2024 |
Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XXXX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; |
01:23:36 Thu Jun 6 2024 |
Critical (3) | UCD invalid or channel unusable;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:23:40 Thu Jun 6 2024 |
Notice (6) | Honoring MDD; IP provisioning mode = IPv6 |
01:24:48 Thu Jun 6 2024 |
Notice (6) | DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
01:24:54 Thu Jun 6 2024 |
Critical (3) | UCD invalid or channel unusable;CM-MAC=XXXX;CMTS-MAC=XXXX;CM-QOS=1.1;CM-VER=3.1; |
All this leads me to suspect there is some noise on the line but I have no idea how to proceed to get it fixed. Please advise.
CCKrista
Retired Employee
•
1.5K Messages
1 year ago
Hello @evilsnoopi3, thank you for taking the time to reach out on social media. I understand your concern with the internet, and I'd like the opportunity to check into that for you.
To access your account, will you please send us a direct message with your full name and complete service address.
To do so, click on the chat icon located at the top right of this forums page.
Here's the detailed steps to direct message us:
0
0
EG
Expert
•
110.9K Messages
1 year ago
@evilsnoopi3 @XfinityKrista
Please circle back here and post any possible solutions for the issue here in these open forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.
0
0
evilsnoopi3
3 Messages
1 year ago
I reached out in a DM and was asked to provide my service address, whether I had any mesh devices, and if I have a separate router from my modem. I confirmed that I do have a separate modem and router and that the router is a mesh system (modem: MB8611, router/mesh system: AX6600). I also informed support that the blips were not limited to wifi and also occurred on wired devices.
Support confirmed "one of your signals is out of spec" and are sending a technician. I will report back if I get more information from the tech.
(edited)
0
EG
Expert
•
110.9K Messages
1 year ago
@evilsnoopi3
Thanks for the update ! Good luck with it !
0
0
evilsnoopi3
3 Messages
1 year ago
Walked the line with the tech. We made a couple of changes to the incoming cable topography with the hopes that it would resolve the issue:
1. We removed an old splitter and connected the feeder line directly to the line leading to my modem as it is the only cable connected device in my home. The tech observed that the splitter could cause noise in two ways: from the rust/age-related degradation and from having a connected, uncapped, unused line.
2. We replaced the filter/line connector which sat between the line coming from the main tap and my condo's cabling. This was more precautionary according to the tech but he did note that the filter/line connector was an older model.
3. We capped the final, open port on the main tap (8 way tap for a condo with 7 units; we capped the 8th); according to the tech this could also be a source of noise.
After all those changes were made I see significant improvement on the Pwr (dBmV) readings for all channels (for example, the OFDM PLC channel went from -0.7 to 2.6 and channels 2 & 3 are now at 10.5 and 10.7 respectively). I will be monitoring the network performance now to determine if this resolves the issue. The tech did indicate the next step if the problem continues would be to replace the cabling for each leg.
0
EG
Expert
•
110.9K Messages
1 year ago
Thanks for the latest ! Hope that stuff does it !!
0
0