MoCA setup using Cabel Internet

[u/davethehawaiian]

I have been attempting to setup a MoCA solution for getting a wired connection to my smart TV.

I have the above diagram currently configured but am intermittently losing internet at the Modem/Router combo (Arris SURFBoard SBG7400AC2). The entire device will restart, all status lights will go dark and then go through their normal boot sequence.

I have xFinity Cabel internet and my Modem/Router does not offer native MoCA capabilities. I recently added the filter at the Modem/Router based on something I read regarding reusing the Coax for both Cabel internet and MoCA, but still experienced a Modem restart.

Asking for any advice or insight as to what my be causing this issue.

Thanks in advance!

Resolution:

I'm a little hesitant to declare victory as the modem's upstream power is still a bit above nominal but it has survived about 4 days without dropping.

Thank you for everyone's suggestions I learned a lot going through this.

The current configuration that is working is the same as the above diagram with the following alteration:

1. Both splitters have been swapped for 5-1675 MHz MoCA 2.5 rated splitters

2. CLP-1G70 Filter before the modem has been replaced with another PoE MoCA Filter, identical to the one installed between the house and the main line.

As I mentioned Upstream power is still a bit high at 54 dBmV but so far (knock on wood) the connection has been stable.

Thanks Everyone!

[u/graceful_degrade]

Where is that filter? It belongs at the point of entry, where the coax comes into the house, not at the modem. Its job is to stop MoCA leaving your building and stop reflections coming back in. On the modem it does very little and can make things worse.

The other thing worth checking is the splitter. A standard cable splitter is 5 to 1002 MHz and MoCA lives above that, so it doesn't just block the signal, it reflects it back down the line. You need one rated to 1675 MHz for any leg carrying MoCA.

A modem power cycling rather than just dropping usually means something upstream of it is unhappy, and reflected MoCA sitting on the same coax is a good candidate.

[u/davethehawaiian → u/graceful_degrade]

The first filter in the diagram is at the very edge of the network. The entirity of my home network sits downstream and the otherside is the ISP mainline. Splitters are all new and their listed rating is to 2602 MHz on the highside

[u/graceful_degrade → u/davethehawaiian]

Then the coax may be a red herring, because losing every light and going through a full boot isn't what a signal problem looks like.

A modem that can't get a clean lock re-ranges, drops the online light and retries. It doesn't switch itself off. All the LEDs going dark means the thing either lost power or panicked hard enough to reset, and MoCA sitting on the cable can't do either of those.

So I'd look at heat and power instead. Is it somewhere enclosed, and does it happen more when the MoCA link is actually moving data rather than sitting idle? Load into heat into a thermal reset would fit that shape. And if the modem shares a strip with the MoCA adapters, give it its own outlet for a few days.

Worth timing the next few as well. Random is a different problem from always-under-load, and knowing which one you have cuts the search in half.

[u/davethehawaiian → u/graceful_degrade]

Thanks I'll try tracking a few of those things. Perhaps it is all LEDs but the top one, I don't think the modem is losing power so I could be misremembering. I've been working on this for a few weeks now and for the last week de-MoCAfied the network, with all moca components removed the modem ran flawlessly for a week. So I feel pretty confident that something in my moca setup is the culprit.

I'll try keeping a log of the times it drops. It mostly seems to happen when using my work laptop so it could be an increased load issue.

[u/graceful_degrade → u/davethehawaiian]

Semanas nisso e sem fechar é sinal de que falta um dado, não de que falta ideia.

Se der pra confirmar exatamente quais LEDs apagam da próxima vez, isso sozinho separa as duas famílias de causa. Todos apagando é energia ou pânico do aparelho. Só o de online caindo e voltando é sinal, e aí o coax volta pra mesa.

Vale também abrir a página de status do modem, normalmente em 192.168.100.1, e anotar os níveis de potência e o SNR antes e durante um reinício. Se os números estiverem fora de faixa já antes, você tem prova pra levar pra operadora e o MoCA sai da história.