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markmich4

join:2004-07-04
Michigan,USA

1 edit

Issues after network upgraded to docsis 3.0

I have a Motorola 5101, docsis 2.0 modem. Was working flawlessly until the cable company "upgraded" the network. When they went to docsis 3.0 that's when my issues began! Of course tech support is clueless to figure out what is happening. Here's what's going on:

I will be surfing the web, data is flowing, but the modem is searching for an upstream signal! I don't understand how I'm able to surf the web while it's searching for a signal, that's odd! At this same time, going into the modem's info page will show that the upstream and downstream frequencies have changed to new values. I have to reset the modem, then it will "lock" onto the new values, but my speeds are greatly reduced. If I then do a factory reset, it'll lock onto the correct "good" frequency (all lights lite), but only to lose it a little while later.

I have realized that there are at least 4 bonded channels out there because of docsis 3.0 and my 2.0 modem looks like it's trying to lock onto any and all of them at any given time.

Now I know most will tell me to talk to the cable company, but I'd like a little more background in figuring out what's going on. I thought it was a configuration file problem that they haven't let my modem know what frequency to use for docsis 2.0, but let me know what everyone thinks is going on.

My signal levels are 0.2dbmv downstream (good) and upstream varies from 43-46.5dbmv. also i'm getting this in the logs when i lose the set of frequencies/channel i'm on..
"3-Critical U002.0 UCD invalid or channel unusable"

any help is appreciated!


TheWiseGuy
Dog And Butterfly
Premium,MVM
join:2002-07-04
East Stroudsburg, PA
kudos:3
Reviews:
·Optimum Online

It sounds as if they have added Dynamic Channel Changes either upstream or downstream. UCD is Upstream Channel Descriptor. Do you see something in the logs saying

-Information C202.0 DCC depart old

It would likely mean with the addition of new channels they are trying to load balance the Docsis 2.0 modems on the downstream or all the modems on the upstream.
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Warning, If you post nonsense and use misinformation and are here to argue based on those methods, you will be put on ignore.



Jabbu
Premium
join:2002-03-06

I agree with the above, looks like your modem does not like the freq. UCD 2 is on, probably around 32mhz. How long has this been happening?


markmich4

join:2004-07-04
Michigan,USA

it's been happening since they upgraded to docsis 3.0, must be about a month or more now, and it's getting quite annoying to keep having to reset the modem. what can i do to make the tech support dept fix this? thanks for the reply, i've never seen such a thing.. and look at that, this minute i begin to type this, there goes the modem again looking for another frequency!


markmich4

join:2004-07-04
Michigan,USA
reply to TheWiseGuy

no i don't see anything like you quote, just the one I had in the log about "UCD invalid or channel unusable". So they're load balancing but then that means they're doing a poor job at it?


TheWiseGuy
Dog And Butterfly
Premium,MVM
join:2002-07-04
East Stroudsburg, PA
kudos:3
Reviews:
·Optimum Online

said by markmich4:

So they're load balancing but then that means they're doing a poor job at it?

Hard to know exactly why the problem is occurring. It could be that the change is to a channel that has noise, or that your modem does not handle DCCs well or that they have something configured incorrectly, etc.
--
Warning, If you post nonsense and use misinformation and are here to argue based on those methods, you will be put on ignore.

markmich4

join:2004-07-04
Michigan,USA

UPDATE: I looked at the log again tonite after another disconnect/resync and I got this:

4-Error C401.0 DCC-ACK not received
3-Critical U002.0 UCD invalid or channel unusable

the "DCC-ACK" is a new one, does this help troubleshoot the problem more? I did speak with one of the techs on the forums here, and he was saying it might be a noise issue on the upstream. But why if it's noise would this happen AFTER they upgraded to DOCSIS 3.0?? I never had issues before that. Let me know thanks again!


zed260
Premium
join:2011-11-11
Cleveland, TN
Reviews:
·Charter

said by markmich4:

UPDATE: I looked at the log again tonite after another disconnect/resync and I got this:

4-Error C401.0 DCC-ACK not received
3-Critical U002.0 UCD invalid or channel unusable

the "DCC-ACK" is a new one, does this help troubleshoot the problem more? I did speak with one of the techs on the forums here, and he was saying it might be a noise issue on the upstream. But why if it's noise would this happen AFTER they upgraded to DOCSIS 3.0?? I never had issues before that. Let me know thanks again!

well sometimes when they upgrade to docsis 3 they combine nodes at the headend

taking my node for instance in 2010 july or so they had a single node on the cmts port i was served though but when they upgraded to docsis 3 they combined it with another node unfortunately that caused noise issues that line techs had to fix

in addition there is also the fact they may have upgraded the upstream qam moving it from 16 to 64 qam which if they did would have made it a lot more suseptble to noise then before

markmich4

join:2004-07-04
Michigan,USA

thanks zed! That makes a lot of sense now, that they upgrade and there is more noise. If this continues I'll definitely talk to the cable technicians and get the line guys to fix the noise issue. That definitely answered my question!


zed260
Premium
join:2011-11-11
Cleveland, TN
Reviews:
·Charter

said by markmich4:

thanks zed! That makes a lot of sense now, that they upgrade and there is more noise. If this continues I'll definitely talk to the cable technicians and get the line guys to fix the noise issue. That definitely answered my question!

have you made any progress

markmich4

join:2004-07-04
Michigan,USA

said by zed260:

have you made any progress

yes thanks for asking, zed. Turns out the technicians have told me that the upgrade to DOCSIS 3.0 did create a lot more noise on the lines than what was there with DOCSIS 2.0, just like you had said! Techs said that the upstream noise was affecting me and many others out of the headend that I am using. Guess they got a lot of noise complaints besides just me. I will keep an eye on it, to see if it resets on its own again, but the responsiveness to downloading data, surfing the web does seem quicker now! Thanks for the help and advice! It was exactly what was going on!