Notice that the introduction section of the document is titled "Information for End Users, Customer Support Technicians, Field Engineers, and Network System Administrators Introduction"
It's hard to imagine that just twenty years ago, we treated users far less like idiots, and gave them plenty of documentation even if they wouldn't read or understand it all.
> All data that is present on the downstream is encapsulated into MPEG-2 frames.
In other words, “you’re now watching The Internet Channel(tm)”
Does anyone remember early cable modems allowing viewing other computers? What allowed that to happen?
I didn't know enough about networking at the time, but I recall seeing this at friends houses in maybe the late 90's. You could go into "Networking" in Windows, and see basically all the PCs on the street/neighborhood. I assume this was with the PC directly connected (no router) and maybe using WINS, but I'd be curious if there's more details behind why this could even happen. Did this also mean you'd be able to sniff other people's network traffic?
I was surprised to see USR still exists, and they even make modems! Doesn’t seem like they’ve done much of any innovation, and now they’re part of some weird IT corp that I can barely understand what they even do. Who makes these websites for enterprise customers? “We sell solutions for your problems”. Ok but what do you actually do?
I didn't think it would combine the downstream cable video as well as "data that is decoded and presented as information available for computer usage (i.e., the Internet). (whatever that means)" into mpeg2 frames.
I was under the impression that internet downstream and upstream are simply operating on different multiple QAM channels in different distinct frequency bands.
I'm surprised this hasn't been mentioned yet - https://www.scribd.com/document/326040021/Defcon-16-Coax-Thi...
It was a big deal back 10 years ago or so. I don't think it'd work nowadays.
https://news.ycombinator.com/item?id=31358855#31362310
MoCA: run your ethernet over the cable tv coax in your house
> That 6 MHz is used to encode MPEG-2 frames containing video, color, and audio information that your cable box or TV decodes into picture and sound. If you graphed a single channel provided by the cable operator, it would look similar to Figure 2-2.
> A DOCSIS channel can be graphed in the same fashion; however, instead of video, color, and audio information inside the MPEG-2 frames, it contains a data stream that represents computer information. Due to the "spectral shaping" of a data signal, there are no video or audio signals present, and the graph looks like Figure 2-3.
this seems wrong. i think figure 2-2 is an analog ntsc video channel and figure 2-3 is a digital mpeg-2 or docsis over mpeg-2 channel. both of the digital channels should have the same spectral envelope.
interesting that they put mpeg-2 headers on the data frames, probably "system" frames and done so for compatibility with existing headend and stb equipment.