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MB8600 New modem error log

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Regular Visitor

MB8600 New modem error log

I just upgraded from a SB6121 to a MB8600. The SB6121 was having issues and dropping communication rather regularly. The MB8600 is working better, but its error log is showing similar errors as the SB6121. Any thoughts on how to proceed?

Here are the errors:

Event Log
   Log  
  
    Time    Priority    Description 
    20:12:22
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:12:44
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:12:44
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:12:44
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:15:59
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:15:59
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:15:59
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:17:52
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:17:52
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:17:52
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:18:34
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:18:34
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:18:34
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:22:05
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:22:05
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:22:05
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:22:37
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:22:37
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:22:37
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:23:36
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:23:36
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:23:36
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:28:07
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:28:07
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:28:07
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:29:15
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:29:15
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:29:15
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:30:00
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:30:00
Tue Jan 28 2020
  Critical (3)   Ranging Request Retries exhausted;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:30:00
Tue Jan 28 2020
  Critical (3)   16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
    20:32:03
Tue Jan 28 2020
  Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:90:23;CMTS-MAC=00:01:5c:70:92:60;CM-QOS=1.1;CM-VER=3.1;
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Regular Visitor

Re: MB8600 New modem error log

Here is the connection status:

Connection
   Startup Sequence    
   Startup Step Status Comment

  
   Acquire Downstream Channel 459000000 Hz Locked
  
   Upstream Connection OK Operational
  
   Boot State OK Operational

  
   Configuration File OK  
  
   Security Enabled BPI+
  


   Connection Status    
   System Up Time 1 days 08h:50m:52s  
  
   Network Access Allowed  
  


   Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 6 489.0 5.8 41.9 0 0
   2 Locked QAM256 7 495.0 6.0 42.0 0 0
   3 Locked QAM256 8 501.0 6.0 42.1 0 0
   4 Locked QAM256 9 507.0 5.7 41.9 0 0
   5 Locked QAM256 10 513.0 5.7 42.0 0 0
   6 Locked QAM256 11 519.0 6.1 42.3 0 0
   7 Locked QAM256 12 525.0 5.8 42.1 0 0
   8 Locked QAM256 13 531.0 5.6 42.0 0 0
   9 Locked QAM256 14 537.0 5.9 42.1 0 0
   10 Locked QAM256 15 543.0 5.6 42.1 0 0
   11 Locked QAM256 16 549.0 5.2 41.9 0 0
   12 Locked QAM256 17 555.0 5.2 41.8 0 0
   13 Locked QAM256 18 561.0 5.6 42.0 0 0
   14 Locked QAM256 19 567.0 5.6 42.1 0 0
   15 Locked QAM256 20 573.0 6.1 42.2 0 0
   16 Locked QAM256 21 579.0 6.5 42.3 0 0
   17 Locked QAM256 22 585.0 6.0 42.1 0 0
   18 Locked QAM256 23 591.0 6.3 42.0 0 0
   19 Locked QAM256 24 597.0 6.7 42.1 0 0
   20 Locked QAM256 25 603.0 6.5 42.0 0 0
   21 Locked QAM256 26 609.0 6.3 41.9 0 0
   22 Locked QAM256 27 615.0 6.8 42.1 0 0
   23 Locked QAM256 28 621.0 6.1 41.8 0 0
   24 Locked QAM256 29 627.0 5.6 41.6 0 0
   25 Locked QAM256 30 633.0 5.7 41.7 0 0
   26 Locked QAM256 31 639.0 5.1 41.5 0 0
   27 Locked QAM256 32 645.0 5.3 41.7 0 0
   28 Locked OFDM PLC 33 690.0 6.6 40.0 6677233 0
   29 Locked QAM256 34 651.0 5.9 41.8 0 0
   30 Locked QAM256 35 657.0 5.5 41.6 0 0
   31 Locked QAM256 36 663.0 4.9 41.2 0 0
   32 Locked QAM256 37 669.0 5.5 41.5 0 0


   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Not Locked SC-QAM 1 5120 17.3 35.8
   2 Not Locked SC-QAM 2 5120 23.7 29.8
   3 Not Locked SC-QAM 3 5120 30.1 32.0
   4 Locked SC-QAM 4 5120 36.5 35.5
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Regular Contributor

Re: MB8600 New modem error log

From your modem stats, your upstream power is a bit low, but that could be normal if you're close to an amp or node.  Based on all the T3 errors in the logs, I'd take a guess that you may be having some sort up upstream singal issue, possibly upstream noise that is 'screaming' over the low upstream power you have.

 

Upstream SNR 'noise' levels can only be read by the Comcast folks.  If/when you're still seeing those T3 errors in the log, try to call into Comcast and ask for your Upstream signal-to-noise levels.  I believe it should be >31.

 

EDIT:  Just noticed that you're only locked on 1 of your 4 upstream channels.  This also points to some sort of upstream issue.  I would also mention this to the Comcast tech support when checking on your upstream singal levels.  The new modem probably didn't fix any issues, but the upstream bonding may have helped mask the issue a bit.

 

I also wonder if there's some sort of upstream filter on your cable drop due to noise or other issues?  I've seen Comcast filter upstream channels with my nieghbors in the past ... not saying this what's happening though.  Just another possibility

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Regular Visitor

Re: MB8600 New modem error log

Thanks for the feedback. There is a splitter from the main cable feed, one side goes to the amplifier for the digital sets and the other goes to the modem. It may be faulty or the wrong type as the lower frequency channels are the ones that are failing. I'll have to check into that.

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Regular Contributor

Re: MB8600 New modem error log

Yep, that's a good catch with the splitter.  If your able to, try jumping out the spitter temporarily and run straight to the modem to see if you can lock all 4 upstream channels.  If that doesn't fix the issue, it seems like something else is blocking/filtering the lower frequencies.

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Expert

Re: MB8600 New modem error log

FWIW, the upstream power is fine. If there were noise ingress in the return path, the modem's upstream power would be commanded to be much higher so that the CMTS could hear it better over the noise floor, not low like it is.

 

Same thing with excessive line attenuation, the power would be higher. The lower power levels typically indicate a very clean and low resistance return path, not a dirty one.



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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New Poster

Re: MB8600 New modem error log

Comcast techs can run an analyis on the line with their Quam constellation meter.  There should be only one splitter before the modem, and it has to have sufficient pass band for all the Quam frequencies, which  a Comcast tech will install. Not all splitters are the same quality

 

If water has gotten in the line, the wire was scuffed, or has a bad bend that is too tight this can affect their connection with the modem to the fiber coax box on the pole somewhere on your street. The meter should agree with what you are seeing on the modem. If not, then the wires should be replaced.

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Expert

Re: MB8600 New modem error log

@154931 

 

Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on. 

 

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.


I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They can check the CMTS (Cable Modem Termination System) for any real time degradation and / or error reports, see your node / cable plant and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !



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Frequent Visitor

Re: MB8600 New modem error log

Mine was simular,
On your channel 28, like mine, I was told by a tech that comcast doesn't use the 690.0 mhz ,hince so many corrected errors.

It in the mb8600 firmware
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Regular Visitor

Re: MB8600 New modem error log

Since it wasn't expensive or difficult, I replaced the old splitter with a new one from Amazon. The old one was 5-1000MHz, the new one is 5-2500MHz. Since the uplink frequencies are on the lower end of the range, I wasn't expecting it to help, but didn't think it would hurt. It didn't help, still have not locked on the 3 lower uplink frequencies. It probably wasn't necessary, as the downlink frequencies are all below 1000MHz.

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Expert

Re: MB8600 New modem error log


@154931 wrote:

Since it wasn't expensive or difficult, I replaced the old splitter with a new one from Amazon. The old one was 5-1000MHz, the new one is 5-2500MHz. Since the uplink frequencies are on the lower end of the range, I wasn't expecting it to help, but didn't think it would hurt. It didn't help, still have not locked on the 3 lower uplink frequencies. It probably wasn't necessary, as the downlink frequencies are all below 1000MHz.


FWIW, you shouldn't use that splitter ! It is engineered to be used with satellite systems. It can actually make things worse by allowing higher frequency noise ingress to pass through rather than it being filtered by a splitter designed for cable systems.



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Regular Visitor

Re: MB8600 New modem error log

That's a good point. I've reviewed the connection reports side by side and the newer splitter does show worse performance. Interesting.