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No Internet & Modem constantly reboots (Upstream power levels too high?)

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No Internet & Modem constantly reboots (Upstream power levels too high?)

See the following status:

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel   Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK  
Security Enabled BPI+

 

 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 5 667750000 Hz 3.4 dBmV 40.3 dB 0 0
2 Locked QAM256 1 643750000 Hz 3.8 dBmV 37.6 dB 0 0
3 Locked QAM256 2 649750000 Hz 3.8 dBmV 40.3 dB 0 0
4 Locked QAM256 3 655750000 Hz 4.6 dBmV 40.3 dB 0 0
5 Locked QAM256 4 661750000 Hz 4.5 dBmV 40.4 dB 0 0
6 Locked QAM256 6 673750000 Hz 3.0 dBmV 39.8 dB 0 0
7 Locked QAM256 7 679750000 Hz 3.0 dBmV 39.8 dB 0 0
8 Locked QAM256 8 685750000 Hz 4.2 dBmV 39.9 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 53.0 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 30100000 Hz 54.0 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 23700000 Hz 54.0 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 17300000 Hz 54.0 dBmV

 

Event log:

 

Fri Aug 02 21:23:48 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:23:00 2019 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:22:28 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:21:40 2019 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:21:08 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:20:20 2019 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:19:48 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:19:01 2019 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:18:28 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:17:41 2019 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:17:08 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:16:41 2019 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:15:38 2019 Warning (5) Unicast DSID PSN startup error
Fri Aug 02 21:15:36 2019 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:15:15 2019 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Fri Aug 02 21:15:11 2019 Notice (6) TLV-11 - unrecognized OID;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Expert

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

The upstream power is too high / out of spec. 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.



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Frequent Visitor

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

It just happened today. Yesterday (Thursday August 1st, 2019) the connection worked fine. 

No cables or other hardware has changed.

Not sure why the customer is immediately blamed. 

Expert

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

No one is blaming you......... Just trying to give you some helpful tips....... Conditions can change just like that ! The problem may lie beyond your premises but this is the first step in troubleshooting..... I'm not an employee..... Pay for a tech visit if you wish..... Good luck with it !



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Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

So it all worked fine again from late last night to early afternoon. But since about 4:30 PM the issues start again. 

I wonder if it has to do with too many people in my building watching Netflix or something. Clearly, Comcast has done nothing to upgrade their aging equipment and cables. I had a look in our basement and the coax cables look ancient. It's a mess down there. And having 12(!) cables connected to the main back bone obviously gives problems.

Expert

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

FWIW, traffic, congestion, bandwidth consumption can not cause those power level / signal / line impairment problems. The problem is physical hardware.



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Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

Here is the log:

 

Sun Aug 04 15:56:17 2019 Warning (5) Unicast DSID PSN startup error
Sun Aug 04 15:55:25 2019 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Sun Aug 04 15:55:25 2019 Warning (5) Unicast DSID PSN startup error
Sun Aug 04 15:43:02 2019 Notice (6) TLV-11 - unrecognized OID;CM-MAC=b8:16:19:31:2a:15;CMTS-MAC=28:52:61:f0:2b:24;CM-QOS=1.1;CM-VER=3.0;
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) No Ranging Response received - T3 time-out
Time Not Established Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INIT
Sun Aug 04 15:41:43 2019 Critical (3) Resetting the cable modem due to docsDevResetNow
Frequent Visitor

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

I decided to buy a new modem & router (now have an Arris gateway, SBG6580)  and see if that helps.

If not, then Comcast can send a technician on their own dime (I"m not gonna pay as I don't own the building, nor the cables). If everything fails, then I have no choice but to switch internet suppliers.

Frequent Visitor

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

Installing the new modem-only device improved the  connection a lot, although only one upstream channel has locked. And the power is still at 52+ dB/mV.

That said, the software indicated that Comcast "purposedly" increased the upstream power. 

 

Download speeds have also improved a lot. I am actually now slightly over my plan limit, while before I was basically at half that.

Expert

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

Good to hear but a new device is not the answer to a line problem.... Sorry if that's not what you want to hear....



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Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

Sorry, but if it is a line-problem then that's out of my hands. 

As I said before, I don't own the building and therefore I don't own the cables running through it. 

Expert

Re: No Internet & Modem constantly reboots (Upstream power levels too high?)

Good luck.



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