Docsis 3.1 and Moca

[Donut417]

In a small way Ive been following Docsis 3.1 development and Moca. I find Moca to be a interesting technology because it allows you to basically use the coax in your house as Ethernet. To my understanding of how the current cable system works, the cable companies use 5mhz to 950mhz. Then Moca uses 1 Ghz to 1.5Ghz. I remember seeing that Docsis 3.1 specs give additional frequencies. Look here: https://www.rohde-schwarz.com/us/technologies/cable_tv/docsis/docsis-technology/docsis_technology_55513.html 

 

My question is, how will this affect Moca? Will the moca specification have to be reviewed and revised for Docsis 3.1? If so, can coax carry larger frequencies? I know I dont need to be worried about this. As Comcast wont upgrade my area any time soon. But its just one of those things Ive had on my brain. Plus I know Comcast and other cable companies use moca. Comcast's X1 platform uses it to communicate between boxes. 

[brwainer]

MoCA 1.0 is technically incompatible with all versions of DOCSIS. But version 2.0 specifically was designed to be used with any version of DOCSIS, it detects what frequencies the ISP has chosen to use (out of the possible 5MHz to 950MHz, cable operators have to choose which of those are going to carry TV cahnnels, which are the upload frequencies, and which are the download ones)

[Donut417]

12 minutes ago, brwainer said:

MoCA 1.0 is technically incompatible with all versions of DOCSIS. But version 2.0 specifically was designed to be used with any version of DOCSIS, it detects what frequencies the ISP has chosen to use (out of the possible 5MHz to 950MHz, cable operators have to choose which of those are going to carry TV cahnnels, which are the upload frequencies, and which are the download ones)

yeah, but Moca 2.0 uses frequencies that ISP's dont use. Because at one time I was researching moca. All the literature stated that moca uses 1Ghz to 1.5Ghz and that cable company's dont go above 950 Mhz.  The upper part. So does that mean Moca 2.0 wont be capable of coexisting with Docsis 3.1? I cant see the cable industry shooting themselves in the foot. As the cable industry is the largest user of Moca specification. 

[brwainer]

4 minutes ago, Donut417 said:

yeah, but Moca 2.0 uses frequencies that ISP's dont use. Because at one time I was researching moca. All the literature stated that moca uses 1Ghz to 1.5Ghz and that cable company's dont go above 950 Mhz.  The upper part. So does that mean Moca 2.0 wont be capable of coexisting with Docsis 3.1? I cant see the cable industry shooting themselves in the foot. As the cable industry is the largest user of Moca specification. 

I'm confused. The whole reason they can coexist is taht they don't overlap. Amplifiers that are used to distribute DOCSIS and QAM signals to/from users (what most of those cable pedestals you see in neighborhoods are) don't even amplify anything above 950MHz (some are as low as 750MHz at the upper end), meaning that without significant upgrades, cable companies aren't even able to use frequencies above that for DOCSIS. (The other reason, or rather, the reason why they don't try to make amplifiers above 950MHz, is that higher frequencies are absorbed by the cabling more, and so travel less. To get a good signal above 950MHz to a user, they'd have to install more pedestals than they already have, and people tend to complain about them a lot already). So with MoCA being even higher freqencies that are only useful inside a small place like a home, there is no issue, hence by they can coexist. If they used the same frequencies, they couldn't coexist. But it is physically impractical, both in the sense of physics and money, to use higher frequencies for DOCSIS.

[Donut417]

32 minutes ago, brwainer said:

I'm confused. The whole reason they can coexist is taht they don't overlap. Amplifiers that are used to distribute DOCSIS and QAM signals to/from users (what most of those cable pedestals you see in neighborhoods are) don't even amplify anything above 950MHz (some are as low as 750MHz at the upper end), meaning that without significant upgrades, cable companies aren't even able to use frequencies above that for DOCSIS. (The other reason, or rather, the reason why they don't try to make amplifiers above 950MHz, is that higher frequencies are absorbed by the cabling more, and so travel less. To get a good signal above 950MHz to a user, they'd have to install more pedestals than they already have, and people tend to complain about them a lot already). So with MoCA being even higher freqencies that are only useful inside a small place like a home, there is no issue, hence by they can coexist. If they used the same frequencies, they couldn't coexist. But it is physically impractical, both in the sense of physics and money, to use higher frequencies for DOCSIS.

Look at the Docsis 3.1 spec, it uses above 1 Ghz. Which why I asked. What frequencies can a coax cable carry? Will they upgrade the Moca standard with just using higher frequencies. 

[brwainer]

I have seen that DOCSIS 3.1 will be capable of using up to 1.2GHz, but that's just the standard. You also have to get the signal into people's homes, which as I explained before is physically impractical. And if a cable company does decide to use up to 1.2GHz for DOCSIS, it won't even matter because MoCA 2 didn't just change the frequencies used, it also added the ability to detect if DOCSIS is using any frequencies.

 

Edit: Long story short, I wouldn't worry about it. And by the time it becomes an issue, I would expect there to be a new version of MoCA out anyway