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Netgear CM1100 - Frequent Loss of Connectivity and Slow Speeds

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Netgear CM1100 - Frequent Loss of Connectivity and Slow Speeds

Over the last 4 days, we've noticed that our connectivity has been dropping a few times each hour. When able to surf online, speeds have also been notably slower than usual, especially for 1 gigabit service.

 

Below are a few of the measures taken so far to resolve the issue:

1. Performed a modem restart courtesy of the Xfinity support section - connectivity issues persisted.

2. Isolated the modem, from our router, by connecting a labtop directly to the modem - connectivity issues persisted.

3. Checked the visible line, outside and inside of the home - ware and tear seemed nominal. Also, no splitters were present.

4. Logged into the modem and checked the firmware, which seems to be up to date (V2.01.02) for the Netgear CM1100.

5. I checked the connection details on the router, which I've pasted below.

6. I checked the connection's event logs, which seems to show several warning and critical errors. Specifically, we're seeing warnings for "MDD message timeout;" and criticals for "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;". I've included a sample below.

Connection Details:

<tabindex=-1>Startup Procedure</tabindex=-1>
Procedure Status Comment
Acquire Downstream Channel 621000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only

<tabindex=-1>Downstream Bonded Channels (Partial Service)</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 33 621000000 Hz 0.4 dBmV 40.0 dB 3535599704 12 68
2 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
3 Locked QAM256 18 531000000 Hz -13.2 dBmV 36.2 dB 618726077 0 0
4 Locked QAM256 19 537000000 Hz -11.0 dBmV 37.5 dB 618729902 0 0
5 Locked QAM256 20 543000000 Hz -7.1 dBmV 39.2 dB 618733397 0 0
6 Locked QAM256 21 549000000 Hz -4.0 dBmV 39.9 dB 618737087 0 0
7 Locked QAM256 22 555000000 Hz -1.6 dBmV 40.1 dB 800318913 1598893292 1005847490
8 Locked QAM256 23 561000000 Hz -1.2 dBmV 39.7 dB 3501340131 1 0
9 Locked QAM256 24 567000000 Hz -1.4 dBmV 40.3 dB 3501348220 0 0
10 Locked QAM256 25 573000000 Hz -1.6 dBmV 40.1 dB 3501355434 0 0
11 Locked QAM256 26 579000000 Hz -1.2 dBmV 40.0 dB 3501359864 0 0
12 Locked QAM256 27 585000000 Hz -0.4 dBmV 39.9 dB 3501363799 0 0
13 Locked QAM256 28 591000000 Hz -0.2 dBmV 40.1 dB 3501369134 0 0
14 Locked QAM256 29 597000000 Hz -0.3 dBmV 40.1 dB 3501373169 0 0
15 Locked QAM256 30 603000000 Hz -0.2 dBmV 40.2 dB 3501377428 0 0
16 Locked QAM256 31 609000000 Hz -0.1 dBmV 40.1 dB 3501382173 0 0
17 Locked QAM256 32 615000000 Hz 0.2 dBmV 40.1 dB 3284284170 0 0
18 Locked QAM256 34 627000000 Hz 0.3 dBmV 40.0 dB 3284288253 0 0
19 Locked QAM256 35 633000000 Hz 0.6 dBmV 40.2 dB 3284293191 0 0
20 Locked QAM256 36 639000000 Hz 0.3 dBmV 39.9 dB 3284297022 0 0
21 Locked QAM256 37 645000000 Hz -0.2 dBmV 40.1 dB 3284301061 0 0
22 Locked QAM256 38 651000000 Hz -0.7 dBmV 39.9 dB 3284307297 0 0
23 Locked QAM256 39 657000000 Hz -0.8 dBmV 39.9 dB 3284311068 0 0
24 Locked QAM256 40 663000000 Hz -0.4 dBmV 39.9 dB 3284316325 0 0
25 Locked QAM256 41 669000000 Hz -0.1 dBmV 40.0 dB 3284322438 0 0
26 Locked QAM256 42 675000000 Hz -0.9 dBmV 39.7 dB 3284326018 0 0
27 Locked QAM256 43 681000000 Hz -1.4 dBmV 39.6 dB 3284331508 0 0
28 Locked QAM256 44 687000000 Hz -2.0 dBmV 39.5 dB 3284336096 0 0
29 Locked QAM256 45 693000000 Hz -1.8 dBmV 39.7 dB 3284362473 0 0
30 Locked QAM256 46 699000000 Hz -2.8 dBmV 39.4 dB 3284344580 0 0
31 Locked QAM256 47 705000000 Hz -2.7 dBmV 39.5 dB 3284346609 0 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 1 36500000 Hz 46.0 dBmV
2 Locked ATDMA 2 30100000 Hz 45.8 dBmV
3 Locked ATDMA 3 23700000 Hz 44.3 dBmV
4 Locked ATDMA 4 17300000 Hz 44.3 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0, 255 48 805000000 Hz -1.9 dBmV 37.5 dB 1348 ~ 2747 7228273960 6944492454 0
2 Not Locked 0, 255 0 0 Hz -51.0 dBmV 0.0 dB 0 ~ 4095 0 0 0

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV

 

 

Event Log Sample:

Time Priority Description
2019-07-29, 19:02:09 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:02:03 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:02:01 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:01:53 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:01:51 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:01:47 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:01:03 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:53 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:39 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:30 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:27 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:25 Notice (6) CM-STATUS message sent. Event Type Code: 4; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:05 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 19:00:00 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:59:52 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:59:47 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:40 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:33 Notice (6) CM-STATUS message sent. Event Type Code: 2; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:27 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:11 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:09 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:03 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:58:01 Notice (6) CM-STATUS message sent. Event Type Code: 6; Chan ID: 3; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:57:59 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:57:31 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:57:25 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:56:27 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:55:30 Notice (6) CM-STATUS message sent. Event Type Code: 2; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:55:27 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:55:10 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:54:41 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:54:24 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:54:22 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:54:13 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:54:12 Notice (6) CM-STATUS message sent. Event Type Code: 4; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:54:12 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:53:59 Warning (5) MDD message timeout;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:53:55 Notice (6) CM-STATUS message sent. Event Type Code: 4; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:53:41 Notice (6) CM-STATUS message sent. Event Type Code: 1; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;
2019-07-29, 18:53:38 Notice (6) CM-STATUS message sent. Event Type Code: 5; Chan ID: 17; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=3c:37:86:eb:64:c8;CMTS-MAC=00:01:5c:a9:6c:57;CM-QOS=1.1;CM-VER=3.1;

 

Any help to resolve this issue would be greatly appreciated.

Expert

Re: Netgear CM1100 - Frequent Loss of Connectivity and Slow Speeds

The downstream stream power is on the low side on a couple of channels and it may be intermittently fluctuating even lower 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.



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New Poster

Re: Netgear CM1100 - Frequent Loss of Connectivity and Slow Speeds

Hello EG,

 

Many thanks for replying! Unfortunatley, there aren't any splitters on the line for me to inspect or replace. The culprit may be a falty line that extends outside of the home, but I don't have direct access to it. I'm wondering if having someone come out to the house may be the next step.

 

Thank you again for the reply!