Community Forum

Xfinity + Motorola MB8600 = horrible (NEED HELP)

New Poster

Xfinity + Motorola MB8600 = horrible (NEED HELP)

TLDR:

  • Motorola MB8600, in the list of officially approved devices
  • Blast Pro, 250Mbps
  • Connection is fine, but it locks up once evefy 24-48 hours
  • When it locks up, cable modem is not accessible via HTTP
  • Internet stops working until you reboot the modem. Modem doesn't recover on its own. Logs have many "No Ranging Response received - T3 time-out"
  • Have to reboot my modem once a day. Especially tough when connection goes away in the middle of important meetings

 

Motorola support:

  • Said that I'm on Docsis 3.1 because downstream channel 32 from my modem connection page says "OFDM PLC"
  • Confirmed that MB8600 has a firmware bug with Docsis 3.1 which causes connection lock ups. Saying engineers are working on a fix (but no ETA)
  • I insisted and they shipped me a replacement modem just to rule out the hardware.  It didn't help, replacement modem also has lock ups
  • Said I should talk to Comcast to switch me from Docsis 3.1 to Docsis 3.0, this is the only solution

Comcast support:

  • Sent a technician to replace all the cables
  • Verified that signal levels are good +1..+3 downstream, 41..43 upstream
  • Sent a network supervisor for me to talk to (good conversation, but didn't yield anything)
  • Claims that Blast Pro boot file (d11_m_mb8600_blastpro_c01.cm) provisions customers using Docsis 3.0
  • They have no procedure of switching me to Doscis 3.0, as I'm already on 3.0
  • Won't let me speak to Tier 2 / Tier 3 teams because I own my own modem (even though it's in the list of approved devices)

So I'm stuck in the middle of Comcast and Motorola, and neither company is able to help me.

 

 

Valued Contributor

Re: Xfinity + Motorola MB8600 = horrible (NEED HELP)

I've had a MB8600 for about a year now and your symptoms sound familiar.  I've had instances where things "lock up" and the indication is slow to no speeds and looking at the modem the activity light on the bottom just goes nuts like there's a flood of activity but, nothing is in use.  Typically a quick power cycle fixed it and then it's good for a couple of days.  Well, that only went on for a couple of weeks and then things stabilized somewhere other than the modem.  A few months went by when things were smooth and stable and then it cropped up again and then went away again.

 

The thing to keep in mind is Comcast is always tweaking things in the network to keep things stable and sometimes fixing one thing leads to another break with something else that prompts another fix.  

 

Everything you listed from the technical stand point falls in line with recommendations you'll get.  I found though that having higher power readings resulted in more stability and speed than say the +1 - +3 you're reporting.  As long as your SNR is where it is currently there's no real leakage or interference that might be causing an issue.  

 

To get the higher power levels though you need to mitigate your splitters and try to get the modem as close to where the line is coming into your home.  If you can't do that then splitting the modem side directly off one side and then the video service (if any) to the other side of the splitter.  

 

When in doubt though if you keep opening tickets with the reps on the phone eventually it becomes a nuisance issue that gets escalated for a Tier 3 technician to diagnose.  It could be something in the plant that needs to be tweaked as well.  There might be a software patch that needs to be applied that got missed as well in the node.

Expert

Re: Xfinity + Motorola MB8600 = horrible (NEED HELP)


@mrumppe wrote:

There might be a software patch that needs to be applied that got missed as well in the node.


Isn't the "node" device a simple media converter that doesn't get "firmware updates" ?



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
Expert

Re: Xfinity + Motorola MB8600 = horrible (NEED HELP)


@mrumppe wrote:

 

 

To get the higher power levels though you need to mitigate your splitters and try to get the modem as close to where the line is coming into your home.  If you can't do that then splitting the modem side directly off one side and then the video service (if any) to the other side of the splitter.  


FWIW, you have always seemed to be focusing on "higher" downstream power levels / anything other than negative numbers or low plus numbers when in fact isn't anything that is closest to 0 dB  perfect ? Sure, there is a range, but their plus numbers aren't all that low / out of spec.  Yes, I do agree that plus numbers are better than minus numbers but as long as they are within that range they are o/k. And you always have to keep the upstream power level numbers in mind because the addition / subtraction of overall attenuation affects both. And I didn't see them post any SNR figures ?



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
Expert

Re: Xfinity + Motorola MB8600 = horrible (NEED HELP)


@ralekseenkov wrote:

 Motorola support:

  • Said I should talk to Comcast to switch me from Docsis 3.1 to Docsis 3.0, this is the only solution

Comcast support:

  • They have no procedure of switching me to Doscis 3.0, as I'm already on 3.0.

FWIW DOCSIS 3.0 and 3.1 co-exist.



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!