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Modem periodically drops connection for 5-10 minutes

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Modem periodically drops connection for 5-10 minutes

My internet keeps going out for 5-10 min almost everyday and today it has happened 3 times so I'm looking for some reasons why this might be occurring.

 

The modem is a brand new Netgear CM500, the RG6 cable is brand new as well and securely connected to the wall cable connection without any kinks.

 

Here is the event log showing the internet going out

2020-7-16, 11:34:15 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-MAC=00:01:5c:73:c0:6a;CM-QOS=1.1;CM-VER=3.0;
2020-7-16, 11:29:47 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-MAC=00:01:5c:73:c0:6a;CM-QOS=1.1;CM-VER=3.0;
2020-7-16, 11:29:47 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-MAC=00:01:5c:73:c0:6a;CM-QOS=1.1;CM-VER=3.0;
2020-7-16, 11:29:47 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-MAC=00:01:5c:73:c0:6a;CM-QOS=1.1;CM-VER=3.0;
2020-7-16, 11:29:36 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-MAC=00:01:5c:73:c0:6a;CM-QOS=1.1;CM-VER=3.0;
2020-7-16, 11:29:32 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-MAC=00:01:5c:73:c0:6a;CM-QOS=1.1;CM-VER=3.0;
2020-7-16, 11:29:32 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=bc:a5:11:eb:4f:ac;CMTS-

 

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Expert

Re: Modem periodically drops connection for 5-10 minutes

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




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Re: Modem periodically drops connection for 5-10 minutes

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 32 585000000 Hz -2.7 dBmV 41.2 dB 13650 5216
2 Locked QAM256 33 591000000 Hz -3 dBmV 41.1 dB 13027 5141
3 Locked QAM256 34 597000000 Hz -3.4 dBmV 40.7 dB 13397 5081
4 Locked QAM256 35 603000000 Hz -3.8 dBmV 40.5 dB 13284 4745
5 Locked QAM256 36 609000000 Hz -3.9 dBmV 40.4 dB 13004 4892
6 Locked QAM256 37 615000000 Hz -4 dBmV 40.4 dB 13093 4818
7 Locked QAM256 38 621000000 Hz -3.6 dBmV 40.5 dB 12964 4279
8 Locked QAM256 39 627000000 Hz -3.6 dBmV 40.5 dB 12916 4322
9 Locked QAM256 40 633000000 Hz -3.6 dBmV 40.5 dB 12269 3848
10 Locked QAM256 41 639000000 Hz -3.7 dBmV 40.2 dB 12633 4128
11 Locked QAM256 42 645000000 Hz -3.8 dBmV 40.4 dB 12456 4216
12 Locked QAM256 43 651000000 Hz -4.1 dBmV 40.3 dB 12578 4065
13 Locked QAM256 44 657000000 Hz -4.5 dBmV 40.2 dB 11834 3501
14 Locked QAM256 45 663000000 Hz -4.7 dBmV 40.1 dB 11681 3711
15 Locked QAM256 46 675000000 Hz -4.9 dBmV 39.8 dB 11573 3501
16 Locked QAM256 47 681000000 Hz -4.7 dBmV 40 dB 10946 3195

 

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 17300000 Hz 52.3 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 36500000 Hz 53.3 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 30100000 Hz 53.5 dBmV
4 Locked ATDMA 3 5120 Ksym/sec 23700000 Hz 53 dBmV
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Expert

Re: Modem periodically drops connection for 5-10 minutes

The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

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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Re: Modem periodically drops connection for 5-10 minutes

Thanks for the informative response, I don't have any control over the configuration of the splitters as I am a renter in an apartment building so I will go ahead and attempt to clean the wall fittings. What upstream power level should I be aiming for to ensure a stable connection?

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Expert

Re: Modem periodically drops connection for 5-10 minutes

In the 40 to 45 area is preferred. Multiple dwelling units are especially troublesome ! It may be best to book a tech visit.

 

Bear in mind that 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.




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