[tavilach]

Does anyone know how things like Cinemax and Showtime On Demand work? My mom was wondering why companies like Netflix use the mail instead of the internet, and I was explaining to her the bandwidth issues that internet distributors and their consumers face. And then she asked me, "So how does On Demand work? It's instant." And I have absolutely no idea. I don't believe that our cable box has a hard drive in it to store the shows as they are added, but I could be wrong. Anyone know how it works?

[turtle777]

Obviously, the mom is smater than her son

-t

[Chuckit]

Cable is not the Internet. In order to get these channels, you must already be (over)paying the cable company for its bandwidth. As far as I can tell, the only difference between these channels and normal cable service is that you're choosing what feed you receive.

As for why Netflix doesn't distribute by the Internet: That isn't its business model. I've heard of some companies that tried to do this, but they're hampered by a couple of things. First of all, people generally don't want to watch movies on their computer; they prefer a TV. Second, everybody already releases movies on DVD. Setting up a completely new distribution model is a very different thing, and working out deals with all the companies to do this (and coming up with adequate DRM to satisfy them) doesn't sound like an easy feat for most people.

[tavilach]

Chuckit, On Demand lets you start the movie whenever you want, pause, rewind, etc. That's not just a cable feed.

And I agree about those other factors regarding Netflix using DVD's by mail. But I do believe that internet bandwidth is also a major concern. You can't get DVD quality movies through the internet at this point.

[Chuckit]

I meant from a bandwidth standpoint. They are already sending you data constantly and you're paying for the infrastructure to do it. In this case, you are simply telling them what data to send.

[tavilach]

Oh, I see.

[TheMosco]

http://www.dslreports.com/forum/remark,14445305

There are limitations to how many video streams a specific node can handle at one time. Each stream takes some part of one of the channel frequencies set aside for VOD. Each node has multiple channels available, but it is limited because the cable network is also using their bandwidth for regular TV channels, internet, & VOIP.

The video streams are transmitted from server farms that are linked to the head end equipment.

So yes, there is a limit to simultaneous streams and it is possible that when you request a VOD program that a stream may not be available. In that case you will get an error msg. Comcast can monitor its streams and it will know when they start to consistently run out of bandwidth on a particular node. In that case, depending on availability of capital money and on technical personnel, they will split your node so that each node no longer is running out of bandwidth.

[Tyler McAdams]

I think most of that is done via multicast routing.