New Modem Flashing DS light

Pegi

Limp Gawd
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May 31, 2005
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Activated a new Motorola MB8611 (docsis 3.1) about three weeks ago. Seems to work fine, although I noticed the blue downstream light will start blinking rather than remain solid every few days. It doesn't affect internet connectivity; I can still connect, still stream, still game. But it will blink continuously. If I turn off the modem, wait a minute, and then turn it back on, the DS light will go solid. For a few days. Then it will blink again.

I question whether the modem is faulty...should I exchange it? It was suggested on the Cox forum that my signal levels aren't at optimal level. Is that what the blinking light is trying to tell me? If so, why would a reboot "fix" it for a few days?

I'm totally a noob, network wise, so I try to keep my modem/router upgraded every few years to avoid any problems. Anyone have any insight what is going on?
 

Nobu

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Iirc, the manual says what it means. Something like you have 2x downstream links if blinking, 4x if solid. My numbers might be wrong, but it's something like that.
 

Nobu

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If you navigate to the modem's management page, it should have a status page which tells you the signal noise and power levels (and a bunch of other stuff), which would also be helpful in diagnosing the problem.
 

Pegi

Limp Gawd
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The manual says blinking blue downstream light means "negotiating bonded channel," with solid blue "bonded with 2 or more channels." It should be solid; I don't understand why it is indeed solid for a few days and then goes back to blinking, requiring a reboot to go solid again. I didn't know if the unit itself was faulty.

The following is my signal noise and power levels.

mb8611.JPG
 

Nobu

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Looks good, except maybe the last channel (it's signal strength is much higher, more than 3dBmv, and also has a lot of uncorrected errors, which may be a problem according to this white paper).

I'd contact a support tech at your cable provider and see if they can diagnose it remotely.
 

Pegi

Limp Gawd
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Looks good, except maybe the last channel (it's signal strength is much higher, more than 3dBmv, and also has a lot of uncorrected errors, which may be a problem according to this white paper).

I'd contact a support tech at your cable provider and see if they can diagnose it remotely.
I am hopeful this is resolved...I had previously neglected to also reboot the router when I rebooted the modem. I just did so; and while, of course, the light no longer flashes, when I checked the status on the modem, all those "uncorrected errors" are now at zero. I hope I was the cause of my own problem, but thanks to all who responded.
 
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Pegi

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I am hopeful this is resolved...I had previously neglected to also reboot the router when I rebooted the modem. I just did so; and while, of course, the light no longer flashes, when I checked the status on the modem, all those "uncorrected errors" are now at zero. I hope I was the cause of my own problem, but thanks to all who responded.
FWIW, the DS light started flashing again yesterday, corrected/uncorrected numbers started showing again in the status columns, and my router (Amplifi Alien with LCD readout) showed network spikes. I honestly don't know if it's the modem (I rue not returning it when I could; I'm 3 days past my return window) or Cox, although I've seen rather vague comments from reviewers about issues with downstreaming with this modem, without any specifics being given. Anyway, since the internet still actually works, I've been emailing with Motorola in the hope of getting an exchange at some point (unless I hear something different, I just feel it is more modem-related than not), but I may just decide to eat the cost and buy another modem. Any reliable suggestions? I do want a 3.1 modem even though I don't have gigablast service.
 

Nobu

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FWIW, the DS light started flashing again yesterday, corrected/uncorrected numbers started showing again in the status columns, and my router (Amplifi Alien with LCD readout) showed network spikes. I honestly don't know if it's the modem (I rue not returning it when I could; I'm 3 days past my return window) or Cox, although I've seen rather vague comments from reviewers about issues with downstreaming with this modem, without any specifics being given. Anyway, since the internet still actually works, I've been emailing with Motorola in the hope of getting an exchange at some point (unless I hear something different, I just feel it is more modem-related than not), but I may just decide to eat the cost and buy another modem. Any reliable suggestions? I do want a 3.1 modem even though I don't have gigablast service.
The network spikes are probably from extra packets being sent to make up for dropped packets.

Have you called your isp (or Motorola) yet? I know tech support isn't always helpful, but they do have some diagnostic tools that might help figure out what is going on before you try swapping modems.

That said, swapping the modem is an option if you don't mind spending the money. Unfortunately I haven't used more than one docsis 3.1 modem (a Netgear, iirc, and just a 40mbps connection), so I can't really give any suggestions afa that goes.
 

SamirD

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If you still have your isp equipment, I would try it in 'modem-only' aka 'bridged' mode and see if you get the same correctables/uncorrectables. If you do, it's just a signal issue with the isp that they can fix. Otherwise, the modem just may be more 'picky' as each of these are literally modulator-demodulators (hence mo-dem) and will look at the signal differently.
 

Pegi

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The network spikes are probably from extra packets being sent to make up for dropped packets.

Have you called your isp (or Motorola) yet? I know tech support isn't always helpful, but they do have some diagnostic tools that might help figure out what is going on before you try swapping modems.

That said, swapping the modem is an option if you don't mind spending the money. Unfortunately I haven't used more than one docsis 3.1 modem (a Netgear, iirc, and just a 40mbps connection), so I can't really give any suggestions afa that goes.
I had called the ISP (Cox) and the tech said everything looked fine on their end. My speedtest score was good. It was then suggested to me about being sure to reboot the router as well as the modem, which I had neglected to do, and doing that seemed to correct the issue. But only for a few days until it cropped up again. I haven't called them back. As mentioned, my speeds are good, I can game online, I can stream (although the resolution takes a few minutes before resolving into something watchable). During this pandemic atmosphere, my husband is not wanting any service techs visiting us if avoidable. I am emailing a Motorola tech. Waiting for his reply.
If you still have your isp equipment, I would try it in 'modem-only' aka 'bridged' mode and see if you get the same correctables/uncorrectables. If you do, it's just a signal issue with the isp that they can fix. Otherwise, the modem just may be more 'picky' as each of these are literally modulator-demodulators (hence mo-dem) and will look at the signal differently.
Hi, Samir, you still using the keyboard? I find your last comment very interesting...the modem being more picky. That was something I was wondering about. This modem is way more than I need, really (I don't have gigablast service). Knowing nothing about networking, I tend to buy the "best" every few years so I needn't worry about it. I wondered whether this modem was either faulty or just, as you say, picky in its communication with Cox. I don't know whether a different modem or a replacement modem would improve the situation or if I just need new cabling (which I want to avoid at this point in time). Everything sorta works, so it's not the end of the world. If I could fix it on my own, so much the better.

At this point in time, the DS light is not flashing anymore (stopped on its own), and that's what I was most concerned about; both corrected and uncorrected columns are totally full of numbers; but my modem speedtest is good. I'll see what Motorola has to say, but if the flashing DS light becomes more persistent, I'll have to explore further.
 

SamirD

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Hi, Samir, you still using the keyboard? I find your last comment very interesting...the modem being more picky. That was something I was wondering about. This modem is way more than I need, really (I don't have gigablast service). Knowing nothing about networking, I tend to buy the "best" every few years so I needn't worry about it. I wondered whether this modem was either faulty or just, as you say, picky in its communication with Cox. I don't know whether a different modem or a replacement modem would improve the situation or if I just need new cabling (which I want to avoid at this point in time). Everything sorta works, so it's not the end of the world. If I could fix it on my own, so much the better.

At this point in time, the DS light is not flashing anymore (stopped on its own), and that's what I was most concerned about; both corrected and uncorrected columns are totally full of numbers; but my modem speedtest is good. I'll see what Motorola has to say, but if the flashing DS light becomes more persistent, I'll have to explore further.
Yep, still typing on a keyboard, but not sure what that has to do with it, lol.

The modem part is what a lot of people forget in cable modems. Back in the day on traditional modems running over phone lines, you could really see the differences in modems capabilities as well as different phone lines. Today with cable modems the variance isn't as apparent, but it does still happen--hence why I was suggesting the test.

If you're continuously upgrading equipment to the top end product, for cable modems it can be a waste of money (depending on how much the modem costs) as the isp equipment is always going to be the top end for their network and is completely supported in case of failure/whatnot without you having to deal with hardware support on your own equipment and the finger-pointing that can come with your own hardware.

If the DS light is solid, it's not an issue. If it's flashing and you don't have any issues, that's odd as you should have upload issues in this case as that's always been my experience (have been dealing with cable Internet for about 15 years now and currently have 3 sites with 4 modems I monitor). If the DS is flashing and you're NOT having upload issues, I'd exchange the modem and try again. If you get the same results and it's not affecting anything, just let it be as someone else will be having worse issues and eventually Cox will fix it without you having to do anything.
 

Pegi

Limp Gawd
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Yep, still typing on a keyboard, but not sure what that has to do with it, lol.

The modem part is what a lot of people forget in cable modems. Back in the day on traditional modems running over phone lines, you could really see the differences in modems capabilities as well as different phone lines. Today with cable modems the variance isn't as apparent, but it does still happen--hence why I was suggesting the test.

If you're continuously upgrading equipment to the top end product, for cable modems it can be a waste of money (depending on how much the modem costs) as the isp equipment is always going to be the top end for their network and is completely supported in case of failure/whatnot without you having to deal with hardware support on your own equipment and the finger-pointing that can come with your own hardware.

If the DS light is solid, it's not an issue. If it's flashing and you don't have any issues, that's odd as you should have upload issues in this case as that's always been my experience (have been dealing with cable Internet for about 15 years now and currently have 3 sites with 4 modems I monitor). If the DS is flashing and you're NOT having upload issues, I'd exchange the modem and try again. If you get the same results and it's not affecting anything, just let it be as someone else will be having worse issues and eventually Cox will fix it without you having to do anything.
I think I'm probably driving myself crazy with this stuff. The DS light flashing just sent me off on a wild goose chase. As long as the light remains solid--and it's solid right now-- think I'll just let it be.

As an aside, I did notice that after I finished playing an online VR game the DS light was flashing and continued flashing for about 5 or 10 minutes. After that, it went steady on its own. My earlier concern was related more to my having to reboot the modem manually in order to return the light to its steady state.

I generally upgrade my modem with every docsis. I went from a 3.0 to this 3.1...and this particular modem is on Cox's approved list. The whole point of this discussion was to figure out if the modem itself was faulty since I was in my return window. That has since passed, so I'll live with it until I can't anymore. I'm going to stop looking at the online modem status report because every time I do the numbers in the corrected and uncorrected columns increase. I don't know what they mean and it only serves to frustrate me, thinking something is wrong.
 

Pegi

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Motorola advised me to return the modem!

That said, they did state that the power level of the upstream bonded channel is out of range.

I will be returning this modem for refund. If I buy another modem (non-Motorola), might I still have issues due to that out-of-range power level? Or might that be handled better/differently by, say, an Arris or Netgear modem? I'm unsure whether to just go back to my older 3.0 docsis modem or buy a new 3.1.
 

jardows

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Motorola advised me to return the modem!

That said, they did state that the power level of the upstream bonded channel is out of range.

I will be returning this modem for refund. If I buy another modem (non-Motorola), might I still have issues due to that out-of-range power level? Or might that be handled better/differently by, say, an Arris or Netgear modem? I'm unsure whether to just go back to my older 3.0 docsis modem or buy a new 3.1.
Fun fact - the Motorola modem you have is manufactured by Zoom. They bought the rights to just the Motorola name for cable modems when Google was selling off the assets they in acquiring Motorola Mobility (Cell phones went to Lenovo). The actual historical Motorola modem (hardware and developmen) was purchased by Arris, and is still produced under the SurfBoard brand.

I used to work as tech support for the Motorola Mobility Broadband / Arris cable modem division. I had and have no problems recommending their hardware over the new "Motorola" modems. I don't have any experience with the Netgear modems, but they seemed solid.
 

Pegi

Limp Gawd
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Messages
233
Fun fact - the Motorola modem you have is manufactured by Zoom. They bought the rights to just the Motorola name for cable modems when Google was selling off the assets they in acquiring Motorola Mobility (Cell phones went to Lenovo). The actual historical Motorola modem (hardware and developmen) was purchased by Arris, and is still produced under the SurfBoard brand.

I used to work as tech support for the Motorola Mobility Broadband / Arris cable modem division. I had and have no problems recommending their hardware over the new "Motorola" modems. I don't have any experience with the Netgear modems, but they seemed solid.
That is interesting information. I've started to see mention of this recently when researching what the heck I should do.

I've ordered the Arris S33, and that should show up in a day or two. I think it's maybe a good thing--for me, anyway--that this particular Arris doesn't have a lot of status lights. Sometimes what I don't know is better for my stress level. And I also upgraded my internet to gigabit. Assuming everything communicates and likes each other, I should be set for the next few years.
 
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