How does Comcasts Video Distribution Network Work?
The Master Headend or does their bit in aggregating and sending the video signals in MPEG format across the CRAN network. From the cran it goes to the various local headends via Multicast UDP through routers. Finally the local hub picks up the signal and converts it to RF to shoot out over the network. There is also a VOD server farm, which could reside in it’s own building or in a regional headend depending on the local archetecture either built by Comcast, or inherited from acquisitions. VOD has been known to spread apart to other larger headends in the region for redundancy. There are various hubs spread out along the plant house the OOB communications equiptment and the VOD (and potentially SDV) edge qams. There are digital controllers that address all of the set top boxes in the area’s. For Scientific Atlanta sites there’s a *NIX based server called the DNCS, while Motorola sites there is a server called the DAC. While DNCS’s and DAC’s pretty much do the exact same job, the way th
