Today, Rogers (in Canada) announced it was ditching it long running project to move to an IPTV platform it had been developping and will adopt Comcast X1. (some $500 million writeoff). Telco IPTV systems use multicasting all the way to the customer's LAN and generally use the Microsoft/Ericcson MediaRoom product suite and compatible STBs. Could a cableco have deployed Mediaroom on a DOCSIS system? Does docsis support multicasting ? I assume it would run on a separate DOCSIS group of NTSC channels on the coax and likely require 2 modems in the home. I am curious on why Rogers would have spent so much time trying to develop its own system. With regards to Comcast X1, is this a very conventional TV on coax system, with a bunch of switched video channels to cater to on-demand services to invividual homes ? Or does X1 use some form of IP connection to deliver "data" for the on-demand content ? (while linear TV still provided in traditional digital channels bundled into an NTSC channel ? BTW, one of the original arguments for Rogers is that cable STBs had proprietary software that was slow to evolve and get new features approved/tested, so they lagged behind the IPTV STB software which didn't require certificatioN/approval by the STB hardware vendors (cisco etc). Has any Cable system converted to IPTV ?