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user_06b179
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Monday, November 28th, 2022 3:40 PM

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Upstream power is poor

My modem status shows "Upstream power is poor (27.3dBmV). The recommended level is from 30 to 55dBmV." All I can see as recommended actions is to remove any splitters (which I don't have) and use good quality coax cable (which I am). Anything else I can do on my end to fix this?

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2 years ago

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BruceW

Gold Problem Solver

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26.3K Messages

2 years ago

My modem status shows "Upstream power is poor (27.3dBmV). ...

Are you having problems with your Internet connection? Do you happen to have an amplifier in the coax line that amplifies the upstream? Also, where are you seeing that message?

Some customers have very low-loss upstream paths and don't need a strong upstream signal.

So that we can better understand your situation please post your Internet plan speed and the following information from your modem or gateway (from http://192.168.100.1 or http://10.0.0.1):

  • model number
  • downstream: power levels, SNR, and error counts
  • upstream: power levels
  • event log, if available (Be sure to remove or blot out any MAC addresses. Forum security processing considers them "personal information" and may prevent the event log from posting if these are present.)
Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

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user_06b179

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5 Messages

2 years ago

  • 1.2 gbps plan, no amplifiers or anything like that, single cable from outside box to the modem. 
  • Getting intermittent packet loss and high latency.
  • model number Netgear CM2000
  • downstream: power levels, SNR, and error counts
    • Startup Procedure
      Procedure Status Comment
      Acquire Downstream Channel 543000000 Hz Locked
      Connectivity State OK Operational
      Boot State OK Operational
      Security Enabled BPI+
      IP Provisioning Mode Honor MDD IPv6 only
       
      Downstream Bonded Channels
      Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
      1 Locked QAM256 20 543000000 Hz 8.2 dBmV 42.9 dB 0 0
      2 Locked QAM256 13 501000000 Hz 9.0 dBmV 43.5 dB 0 0
      3 Locked QAM256 14 507000000 Hz 8.3 dBmV 43.1 dB 0 0
      4 Locked QAM256 15 513000000 Hz 8.1 dBmV 42.9 dB 0 0
      5 Locked QAM256 16 519000000 Hz 8.9 dBmV 43.6 dB 0 0
      6 Locked QAM256 17 525000000 Hz 8.2 dBmV 43.0 dB 0 0
      7 Locked QAM256 18 531000000 Hz 9.0 dBmV 43.4 dB 0 0
      8 Locked QAM256 19 537000000 Hz 9.4 dBmV 43.7 dB 0 0
      9 Locked QAM256 21 549000000 Hz 9.1 dBmV 43.5 dB 0 0
      10 Locked QAM256 22 555000000 Hz 8.5 dBmV 43.2 dB 0 0
      11 Locked QAM256 23 561000000 Hz 7.7 dBmV 42.6 dB 0 0
      12 Locked QAM256 24 567000000 Hz 8.3 dBmV 43.2 dB 0 0
      13 Locked QAM256 25 573000000 Hz 6.3 dBmV 41.9 dB 0 0
      14 Locked QAM256 26 579000000 Hz 6.4 dBmV 41.9 dB 0 0
      15 Locked QAM256 27 585000000 Hz 6.6 dBmV 42.3 dB 0 0
      16 Locked QAM256 28 591000000 Hz 5.1 dBmV 41.2 dB 0 0
      17 Locked QAM256 29 597000000 Hz 5.8 dBmV 41.6 dB 0 0
      18 Locked QAM256 30 603000000 Hz 5.7 dBmV 41.6 dB 0 0
      19 Locked QAM256 31 609000000 Hz 4.6 dBmV 40.7 dB 0 0
      20 Locked QAM256 32 615000000 Hz 6.4 dBmV 42.0 dB 0 0
      21 Locked QAM256 33 621000000 Hz 5.3 dBmV 41.2 dB 0 0
      22 Locked QAM256 34 627000000 Hz 4.2 dBmV 40.4 dB 0 0
      23 Locked QAM256 35 633000000 Hz 5.0 dBmV 41.1 dB 0 0
      24 Locked QAM256 36 639000000 Hz 4.8 dBmV 40.8 dB 0 0
      25 Locked QAM256 37 645000000 Hz 4.6 dBmV 40.8 dB 0 0
      26 Locked QAM256 38 651000000 Hz 5.8 dBmV 41.5 dB 0 0
      27 Locked QAM256 39 657000000 Hz 4.7 dBmV 40.6 dB 0 0
      28 Locked QAM256 40 663000000 Hz 4.7 dBmV 40.7 dB 0 0
      29 Locked QAM256 41 669000000 Hz 5.8 dBmV 41.5 dB 0 0
      30 Locked QAM256 42 675000000 Hz 5.6 dBmV 40.5 dB 0 0
      31 Locked QAM256 43 681000000 Hz 5.9 dBmV 41.4 dB 0 0
      32 Locked QAM256 44 687000000 Hz 6.2 dBmV 41.7 dB 0 0
       
      Upstream Bonded Channels
      Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
      1 Locked ATDMA 18 5120 Ksym/sec 22800000 Hz 28.5 dBmV
      2 Locked ATDMA 17 5120 Ksym/sec 16400000 Hz 27.3 dBmV
      3 Locked ATDMA 19 5120 Ksym/sec 29200000 Hz 30.3 dBmV
      4 Locked ATDMA 20 5120 Ksym/sec 35600000 Hz 31.5 dBmV
      5 Not Locked Unknown 0 0 0 0.0 dBmV
      6 Not Locked Unknown 0 0 0 0.0 dBmV
      7 Not Locked Unknown 0 0 0 0.0 dBmV
      8 Not Locked Unknown 0 0 0 0.0 dBmV
       
      Downstream OFDM Channels
      Channel Lock Status Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier
      Number Range      		 Unerrored
      Codewords      		 Correctable
      Codewords      		 Uncorrectable
      Codewords
      1 Locked 0 ,1 ,2 ,3 193 957000000 Hz 3.28 dBmV 39.2 dB 148 ~ 3947 354159277 256720192 0
      2 Not Locked 0 0 0 Hz 0 dBmV 0 dB 0 ~ 4095 0 0 0
       
      Upstream OFDMA Channels
      Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
      1 Not Locked 0 0 0 Hz 0 dBmV
      2 Not Locked 0 0 0 Hz 0 dBmV
  • upstream: power levels
  • event log, if available (Be sure to remove or blot out any MAC addresses. Forum security processing considers them "personal information" and may prevent the event log from posting if these are present.)
    • Time Not Established (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxxxx;CM-QOS=1.1;CM-VER=3.1;
      Time Not Established (Warning (5)) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=xxxxx
      Time Not Established (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxxx
      Time Not Established (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=xxxx
      Time Not Established (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=xxxxx
      Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
      Time Not Established (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx
      Time Not Established (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
      Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xxxx;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 16:08:49 2022 (Critical (3)) Resetting the cable modem due to docsDevResetNow
      Mon Nov 28 09:48:31 2022 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xxxxx;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:22:37 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:22:31 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:22:30 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx
      Mon Nov 28 03:22:29 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx
      Mon Nov 28 03:22:06 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxxx
      Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xxxx
      Mon Nov 28 03:20:52 2022 (Critical (3)) Resetting the cable modem due to docsDevResetNow
      Mon Nov 28 03:19:11 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx
      Mon Nov 28 03:18:46 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=xxxx;CM-QOS=1.1;CM-VER=3.1;
      Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xxxx;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:15:19 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=x;CMTS-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:15:17 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=x;CMTS-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:15:07 2022 (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:14:00 2022 (Critical (3)) UCD invalid or channel unusable;CM-MACx;CMTS-MAC=xCM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:13:29 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=x;CMTS-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=x;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:02:17 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:02:15 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Mon Nov 28 03:01:52 2022 (Critical (3)) UCD invalid or channel unusable;CM-MAC=x;CM-QOS=1.1;CM-VER=3.1;
      Time Not Established (Critical (3)) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=x;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

(edited)

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BruceW

Gold Problem Solver

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26.3K Messages

2 years ago

Thank you. Downstream signals look good. The upstream is a bit low, but we really need to know:

  • Are you having problems with your Internet connection?
  • Do you happen to have an amplifier in the coax line that amplifies the upstream?

And out of curiosity, where are you seeing that "Upstream power is poor" message?

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

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user_06b179

Visitor

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5 Messages

2 years ago

  • Are you having problems with your Internet connection?
    • I am getting packet losses (it varies ... up to 50%)
    • I see a lot of correctable errors: 256720192 ... is that normal?
  • Do you happen to have an amplifier in the coax line that amplifies the upstream?
    • I don't have an amplifier

  • And out of curiosity, where are you seeing that "Upstream power is poor" message?

    • I see it in the modem menu (192.168.100.1) under connection status
    • Also, please note that connection was even worst when I used the xFI Gateway (XB8). It improved after I activated the CM2000 but I'm still having problems.

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BruceW

Gold Problem Solver

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26.3K Messages

2 years ago

I see a lot of correctable errors: 256720192 ... is that normal?

On an OFDM channel yes, this is normal.

I am getting packet losses (it varies ... up to 50%)

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you can't find the problem or you'd rather have Comcast take care of it, and if any Employee doesn't respond to your message here, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit ($70-$100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

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