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SoonerDave's avatar
SoonerDave
New Contributor
3 years ago

SB8200 lost upstream bonded channels - power too low

For about one year now, I've had an Arris SB8200 cablemodem and Cox 300Mbps Internet tier, and this has worked esssentially flawlessly in that time. I've had Cox Internet even longer with very few issues - until about two days ago. 

I noticed decreased download speeds, and when I logged into my account, I was notified that an "issue" in my area was detected, and I assumed my speed issue would be resolved when the issue was solved. About two hours later, the issue was clear, but my Internet speeds were still decidedly abnormal. I then noticed that the middle-two lights on the front panel of the cablemodem indicated the *downstream* connection was  DOCSIS 3.1 (bonded downstream), colored blue, but the *upstream* light was now *green*, indicating only DOCSIS 3.0. This is a change from the previous behavior in which both up and down lights were bonded (blue).

That was two days ago. The problem has persisted, across multiple reboots of my cablemodem, and reboots of the firewall appliance that receives the Ethernet out from the cablemodem. I contacted Cox and they said the signal looked clear, but they agreed that my struggle to reach 200Mbps (usually topping out around 170-190) is not consistent with the 300Mbps service tier. They went so far as to re-provision the modem, all to no avail. 

I took a look at my cablemodem serivce page, and it shows that the upstream channels hover between 39.0 and 42 dBmV. I found that Arris states the required upstream signal must be between 45-55 dBmV.  

A bit of Googling has revealed a bit of warfare normally has to be undertaken to get Cox to increase power to the upstream channels, which is precisely what the Arris tech support rep told me when I reached out to them for assistance (cablemodem is only one year old and under warranty). He flatly stated the ISP must increase channel strength. Excerpt of my upstream channel status listed below:

1 1 Locked SC-QAM Upstream 17400000 Hz 6400000 Hz 42.0 dBmV
2 2 Locked SC-QAM Upstream 23900000 Hz 6400000 Hz 42.0 dBmV
3 3 Locked SC-QAM Upstream 30300000 Hz 6400000 Hz 41.0 dBmV
4 4 Locked SC-QAM Upstream 36700000 Hz 6400000 Hz 41.0 dBmV
5 6 Locked SC-QAM Upstream 12600000 Hz 3200000 Hz 39.0 dBmV

I traced the line all the way back to the Cox input, eliminating an intermediate cable in the attic, and directly attached the Cox coax to the cablemodem and powered it up - no difference - bonded down, unbonded up. This means the signal to the modem from Cox is too low. But if I know from research Arris says Cox has to increase power, but Cox will refuse, what on earth do I do? Go out and drop another $200 on a new/different cablemodem? 

Any suggestions appreciated. 

-sd

bonded upstream
sb8200
speed problem
  • JonathanJ's avatar
    JonathanJ
    Former Moderator
    3 years ago
    @SoonerDave

    I apologize for any inconvenience this has caused. You mentioned rebooting the modem. Have you tried a factory reset? Check page 13 in the manual link provided www.cox.com/.../Arris_SB8200_user_guide.pdf. If you are still having the same issue we may need to schedule a technician visit. If so please email your account details to cox.help@cox.com.

    Jonathan J
    Cox Moderator
      • DavidA2's avatar
        DavidA2
        Former Moderator
        3 years ago
        @SoonerDave,

        I am sorry to hear that. Please feel free to email us to the email JJ sent you. We would be happy to schedule a service visit for you.

        David
        Cox Support Forum Moderator
  • Bruce's avatar
    Bruce
    Honored Contributor III
    3 years ago

    Arris would recommend the same specs to a Verizon customer as they would a Cox customers.  Only a provider can verify the correct specs (Up Power) because its their network, hardware, firmware, etc.  As a Cox customer with a different plan and equipment, I'd generally have different specs.

    The outage may not have been in your area but instead farther upstream to effect your area.  You've got basic connectivity now but it's just not efficient.  I'd give Cox a couple days to finish whatever they may be troubleshooting.

    If you didn't need a signal booster in your home before...you probably won't need a signal booster.

  • Bruce's avatar
    Bruce
    Honored Contributor III
    3 years ago

    Your service was "esssentially flawlessly" on 11 May, so everything within your demarc is fine.  After the issue in your area, your upstream seems to have not fully bonded because I only see 5 channels as opposed to 8.  Try logging into your Cox account to reset your connection.

    • SoonerDave's avatar
      SoonerDave
      New Contributor
      3 years ago

      I've reset my connection probably ten times in the last three days. No difference. Cox truck is coming tomorrow.

    • SoonerDave's avatar
      SoonerDave
      New Contributor
      3 years ago

      I agree, and I've told this to each of the four different people I've "chatted" with AND the level 2 tech who talked to me on the phone the other day. I've made a point of saying this seemed to have started with an outage affectingy area. Yet the last word from Cox is for a truck roll. 

      This is another aspect of my frustration: When I mentioned this to the first agent with whom I chatted he told me he would escalate it because of the outage being coincident with my issue. I waited for a couple of hours and checked back, told the next tech the situation, and they said there was no record of any tech escalating anything on my account to anyone for any reason. So I was lied to to get someone's chat resolution metrics inline. And I still have the problem.

      I chatted with, as I recall, four different agents, got disconnected twice, and then told I had to pay for more diagnosis. That's when I about threw my phone through a wall. Then I called tech support and they related me to a (supposedly) Tier 2 who finally concluded a truck roll was necessary because everything in their end looked correct. I told them about the outage but it made no difference to them. 

      • SoonerDave's avatar
        SoonerDave
        New Contributor
        3 years ago

        Just an update: Tech came out today and measured from pedestal to demarc and said downstream signals were OK but not ideal, and agreed upstream signals are too low. He replaced the box (coupler) at the demarc, then measured on the line from the demarc to the outlet, and said the line from the demarc to the outlet should be re-run.

        He was exceptionally nice and I was very impressed with him. He will return in the morning to run the new line in our attic before the temperature hits broil.