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Forum Discussion

greeno's avatar
greeno
Apprentice
Apr 27, 2019

cm600 xfinity T3 error then bufferbloat

Hi, i have blast pro (250down/10up) with xfinity in 94550.  the cm600, firmware version shows V1.01.18,  is connected to a ubiquiti edgerouter-x running latest 1.10.9 firmware.  i use the smart que...
greeno's avatar
greeno
Apprentice
Apr 27, 2019

i've had 2 service call checking connector from the street to the house.  signal levels are nominal.

we've done the basic trouble shooting.  the timeouts are intermittent as i said. 

not the errors.  this is since a reboot 3 days ago, the last t3 error.

 

here's the down/up:

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency
 
Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 597000000 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</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 22 597000000 Hz -8.6 dBmV 37.3 dB 44 0
2 Locked QAM256 1 465000000 Hz -6.2 dBmV 39.2 dB 1577 3345
3 Locked QAM256 2 471000000 Hz -6.4 dBmV 39.2 dB 4 0
4 Locked QAM256 3 477000000 Hz -6.4 dBmV 39.2 dB 7 0
5 Locked QAM256 4 483000000 Hz -6.3 dBmV 39.2 dB 5 0
6 Locked QAM256 5 489000000 Hz -6.4 dBmV 39.2 dB 1 0
7 Locked QAM256 6 495000000 Hz -6.5 dBmV 39.2 dB 2 0
8 Locked QAM256 7 507000000 Hz -6.7 dBmV 34.8 dB 13 0
9 Locked QAM256 9 519000000 Hz -6.9 dBmV 38.9 dB 3 0
10 Locked QAM256 13 543000000 Hz -8.0 dBmV 38.0 dB 24 0
11 Locked QAM256 14 549000000 Hz -8.0 dBmV 38.0 dB 20 0
12 Locked QAM256 15 555000000 Hz -8.0 dBmV 38.0 dB 19 0
13 Locked QAM256 16 561000000 Hz -8.2 dBmV 37.7 dB 19 0
14 Locked QAM256 17 567000000 Hz -8.3 dBmV 37.6 dB 20 0
15 Locked QAM256 18 573000000 Hz -8.4 dBmV 37.6 dB 16 0
16 Locked QAM256 19 579000000 Hz -8.5 dBmV 37.5 dB 37 0
17 Locked QAM256 20 585000000 Hz -8.4 dBmV 37.5 dB 0 0
18 Locked QAM256 21 591000000 Hz -8.5 dBmV 37.5 dB 0 0
19 Locked QAM256 23 603000000 Hz -8.6 dBmV 37.1 dB 0 0
20 Locked QAM256 24 609000000 Hz -8.5 dBmV 37.2 dB 0 0
21 Locked QAM256 26 621000000 Hz -8.7 dBmV 36.9 dB 0 0
22 Locked QAM256 27 627000000 Hz -9.0 dBmV 36.5 dB 0 0
23 Locked QAM256 28 633000000 Hz -9.0 dBmV 36.5 dB 0 0
24 Locked QAM256 32 657000000 Hz -9.2 dBmV 36.2 dB 0 0

 

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 3 5120 Ksym/sec 30300000 Hz 51.3 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 17300000 Hz 49.8 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 23700000 Hz 50.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 36700000 Hz 52.3 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
  • greeno's avatar
    greeno
    Apprentice
    Apr 27, 2019

    persaonally i feel that it is plant noise.  we had that years ago and was why i left comcast.  but we came back because att was too slow.  it's been good for nearly 2 years... not intermittently bad. but at least i can fix it.

     

    i was hoping it might be a modem issue that could be fixed by firmware... i guess not?

    • plemans's avatar
      plemans
      Guru - Experienced User
      Apr 27, 2019

      Your power levels are out of sync. Your upstream levels are a bit to high and your downstream is a bit to low. Your best download is just within spec and your worse is out of spec.  Its imbalanced and out of spec.  Here's a website with some basic specs that are easy to interpret.

      https://pickmymodem.com/signal-levels-docsis-3-03-1-cable-modem/

       

      Did you go through and check connectors, cables, splitters? I had a cable with water in it once that caused an imbalance. I would more your router to right where it comes into your house and connect there to see what your connections are. this reduces the chances of bad connections/wires/splitters causing the issue. If you move the modem, post back here what the signals change to. 

      • greeno's avatar
        greeno
        Apprentice
        Apr 27, 2019

        there's a splitter infront of the cm600 to feed the xfinity digital voice.  i've removed that splitter and the levels are instantly better:

         

        <tabindex=-1>Downstream Bonded Channels</tabindex=-1>
        Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
        1 Locked QAM256 22 597000000 Hz -4.9 dBmV 38.5 dB 0 0
        2 Locked QAM256 1 465000000 Hz -2.3 dBmV 40.0 dB 0 0
        3 Locked QAM256 2 471000000 Hz -2.7 dBmV 39.9 dB 0 0
        4 Locked QAM256 3 477000000 Hz -2.7 dBmV 39.9 dB 0 0
        5 Locked QAM256 4 483000000 Hz -2.7 dBmV 39.9 dB 0 0
        6 Locked QAM256 5 489000000 Hz -2.8 dBmV 39.9 dB 0 0
        7 Locked QAM256 6 495000000 Hz -2.9 dBmV 39.9 dB 0 0
        8 Locked QAM256 15 555000000 Hz -4.5 dBmV 38.9 dB 0 0
        9 Locked QAM256 16 561000000 Hz -4.6 dBmV 38.7 dB 0 0
        10 Locked QAM256 17 567000000 Hz -4.8 dBmV 38.7 dB 0 0
        11 Locked QAM256 18 573000000 Hz -4.8 dBmV 38.7 dB 0 0
        12 Locked QAM256 19 579000000 Hz -4.8 dBmV 38.6 dB 0 0
        13 Locked QAM256 20 585000000 Hz -4.6 dBmV 38.8 dB 0 0
        14 Locked QAM256 21 591000000 Hz -4.7 dBmV 38.6 dB 0 0
        15 Locked QAM256 23 603000000 Hz -4.9 dBmV 38.5 dB 0 0
        16 Locked QAM256 24 609000000 Hz -4.7 dBmV 38.6 dB 0 0
        17 Locked QAM256 25 615000000 Hz -4.7 dBmV 38.5 dB 0 0
        18 Locked QAM256 26 621000000 Hz -4.9 dBmV 38.2 dB 0 0
        19 Locked QAM256 27 627000000 Hz -5.2 dBmV 37.9 dB 0 0
        20 Locked QAM256 28 633000000 Hz -5.3 dBmV 37.8 dB 0 0
        21 Locked QAM256 29 639000000 Hz -5.4 dBmV 37.8 dB 0 0
        22 Locked QAM256 30 645000000 Hz -5.5 dBmV 37.5 dB 0 0
        23 Locked QAM256 31 651000000 Hz -5.5 dBmV 37.6 dB 0 0
        24 Locked QAM256 32 657000000 Hz -5.6 dBmV 37.5 dB 0 0
         
        <tabindex=-1>Upstream Bonded Channels</tabindex=-1>
        Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
        1 Locked ATDMA 2 5120 Ksym/sec 23700000 Hz 47.3 dBmV
        2 Locked ATDMA 1 5120 Ksym/sec 17300000 Hz 47.0 dBmV
        3 Locked ATDMA 3 5120 Ksym/sec 30300000 Hz 48.0 dBmV
        4 Locked ATDMA 4 5120 Ksym/sec 36700000 Hz 49.3 dBmV
        5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
        6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
        7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
        8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

         

        i'm not sure what to do about this... so next text is disconnect the voice modem and reintroduce the splitter...