Netgear CBR750 speed drops after Config File Rejected due to Invalid or Unexpected TLV 11

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What do the modem's signal stats look like ?

Please also copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

  Here are the Error Log entries from a previous restart until the one I had to do this morning after the speed dropped.

Apr 28 2023 04:31:18 Notice (6) CM-STATUS message sent. Event Type Code: 24
Apr 28 2023 05:01:08 Critical (3) No Ranging Response received - T3 time-out
Apr 28 2023 08:39:55 Notice (6) DS profile config update. DS Chan ID: 193.
Apr 28 2023 08:55:23 Critical (3) No Ranging Response received - T3 time-out
Apr 28 2023 10:17:40 Notice (6) CM-STATUS message sent. Event Type Code: 24
Apr 28 2023 10:42:29 Critical (3) No Ranging Response received - T3 time-out
Apr 28 2023 12:01:34 Alert (2) CM Certificate Error
Apr 28 2023 15:25:23 Critical (3) No Ranging Response received - T3 time-out
Apr 29 2023 09:23:50 Notice (6) CM-STATUS message sent. Event Type Code: 16
Apr 29 2023 12:00:51 Alert (2) CM Certificate Error
Apr 29 2023 12:01:50 Notice (6) CM-STATUS message sent. Event Type Code: 16
Apr 29 2023 12:46:07 Critical (3) No Ranging Response received - T3 time-out
Apr 29 2023 12:49:37 Notice (6) CM-STATUS message sent. Event Type Code: 24
Apr 29 2023 17:05:22 Critical (3) No Ranging Response received - T3 time-out
Apr 30 2023 09:32:28 Notice (6) CM-STATUS message sent. Event Type Code: 24
Apr 30 2023 12:00:41 Alert (2) CM Certificate Error
Apr 30 2023 13:48:15 Critical (3) No Ranging Response received - T3 time-out
Apr 30 2023 15:22:26 Notice (6) CM-STATUS message sent. Event Type Code: 24
Apr 30 2023 20:07:21 Critical (3) No Ranging Response received - T3 time-out
Apr 30 2023 20:09:03 Notice (6) CM-STATUS message sent. Event Type Code: 24
May 01 2023 08:58:42 Notice (6) DS profile config update. DS Chan ID: 193.
May 01 2023 09:04:04 Notice (6) CM-STATUS message sent. Event Type Code: 24
May 01 2023 09:32:15 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
May 01 2023 09:32:15 Notice (6) TLV-11 - unrecognized OID
May 01 2023 09:32:15 Critical (3) Config File Rejected due to Invalid or Unexpected TLV 11
May 01 2023 09:32:26 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW
May 01 2023 09:32:36 Alert (2) CM Certificate Error

  Here are the current modem stats.

Current time: Mon May  1 15:28:34 2023

Startup Procedure
Acquire Downstream Channel: 573000000 Hz   Locked
Connectivity State:          Ok       Operational
Boot State:                  Ok       Operational
Security:                   Enabled   BPI+
IP Provisioning Mode:       Honor MDD   honorMdd(4)

Downstream Bonded Channels
Channel LockedStatus Modulation ChannelID  Frequency        Power       SNR   Correctables Uncorrectables     
      1     Locked     QAM 256     13     531000000 Hz     -0.2     40.9     0     0
      2     Locked     QAM 256     14     537000000 Hz     0.0     40.9     0     0
      3     Locked     QAM 256     15     543000000 Hz     0.4     40.9     0     0
      4     Locked     QAM 256     16     549000000 Hz     0.2     40.9     5     0
      5     Locked     QAM 256     17     555000000 Hz     0.0     40.3     0     0
      6     Locked     QAM 256     18     561000000 Hz     -0.2     40.3     2     0
      7     Locked     QAM 256     19     567000000 Hz     0.4     40.3     2     0
      8     Locked     QAM 256     20     573000000 Hz     0.7     40.3     0     0
      9     Locked     QAM 256     21     579000000 Hz     0.7     40.9     0     0
     10     Locked     QAM 256     22     585000000 Hz     0.5     40.9     0     0
     11     Locked     QAM 256     23     591000000 Hz     0.7     40.9     0     0
     12     Locked     QAM 256     24     597000000 Hz     0.7     40.9     0     0
     13     Locked     QAM 256     25     603000000 Hz     1.4     40.9     0     0
     14     Locked     QAM 256     26     609000000 Hz     0.9     40.9     4     0
     15     Locked     QAM 256     27     615000000 Hz     1.0     40.9     0     0
     16     Locked     QAM 256     28     621000000 Hz     1.4     40.9     0     0
     17     Locked     QAM 256     29     627000000 Hz     1.2     40.9     0     0
     18     Locked     QAM 256     30     633000000 Hz     0.7     40.9     0     0
     19     Locked     QAM 256     31     639000000 Hz     0.5     40.9     0     0
     20     Locked     QAM 256     32     645000000 Hz     1.0     40.9     0     0
     21     Locked     QAM 256     33     651000000 Hz     1.7     40.9     0     0
     22     Locked     QAM 256     34     657000000 Hz     0.9     40.3     0     0
     23     Locked     QAM 256     35     663000000 Hz     0.0     40.3     0     0
     24     Locked     QAM 256     36     669000000 Hz     0.2     40.3     0     0
     25     Locked     QAM 256     37     675000000 Hz     1.2     40.3     0     0
     26     Locked     QAM 256     38     681000000 Hz     1.2     40.9     0     0
     27     Locked     QAM 256     39     687000000 Hz     0.2     40.3     0     0
     28     Locked     QAM 256     40     693000000 Hz     -1.0     40.9     0     0
     29     Locked     QAM 256     41     699000000 Hz     -0.2     40.3     0     0
     30     Locked     QAM 256     42     705000000 Hz     0.9     40.9     0     0
     31     Locked     QAM 256     43     711000000 Hz     0.7     40.9     0     0
     32     Locked     QAM 256     44     717000000 Hz     -0.7     40.9     0     0

Upstream Bonded Channels
Channel   LockedStatus  ChannelType ChannelID   SymbolRate        Frequency       Power     
      1       Locked       ATDMA     22       2560       10400000 Hz       46.3
      2       Locked       ATDMA     20       5120       16400000 Hz       46.5
      3       Locked       ATDMA     19       5120       22800000 Hz       47.3
      4       Locked       ATDMA     18       5120       29200000 Hz       48.3
      5       Locked       ATDMA     17       5120       35600000 Hz       48.8
      6       Locked       ATDMA     21       2560       40400000 Hz       49.0
      7       Not Locked       N/A      0       0       0 Hz       0.0
      8       Not Locked       N/A      0       0       0 Hz       0.0

Downstream OFDM Channels
Channel   LockedStatus  ProfileID  ChannelID    Frequency       Power       SNR/MER    ActiveSubcarrier    Unerror    Correctable   Uncorrectable
      1     Locked     3      193     805000000 Hz     -2.5 dBmV     42.1 dB     1168~2927     0     0     0
      2     Not Locked     0      0     0 Hz     0.0 dBmV     0.0 dB     0~4095     0     0     0

Upstream OFDMA Channels
Channel   LockedStatus    ProfileID    ChannelID    Frequency       Power
      1     Not Locked     0      0     0 Hz     0.0 dBmV
      2     Not Locked     0      0     0 Hz     0.0 dBmV

This may or may not be the root cause of the problem (YMMV) but it should be addressed regardless. 

The upstream power is on the high side on channels 4, 5, and 6 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 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, abrasions, 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 perhaps it's best to book a tech visit to investigate and correct.

Good luck with it !

  Thanks for the reply EG.

  The first thing I did was have a Tech visit, actually Xfinity texted me to initiate it.  He checked things from the street box all the way to my router, replaced all the connectors and the single 2 way splitter.  He had a signal meter and said everything checked out on that as well.  Seems like he already did everything you listed, but the speed drops and errors still continue.

  Is there anything else that can be done to resolve this?