Multicast IPTV on DOCSIS

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

Has any Cable system converted to IPTV ?

Yes it works over docsis, you assigned downstreams to part of a multicast group and the CMTS will use those when a device asks to join.

X1 is both traditional HFC and also full on IPTV which is where everyone is going including HFC plants.

Mediaroom is the least popular middleware when looking at the major ones, Minerva has much more market share.

Cox licensed the X1 platform for their Contor product after ditching Cisco for some reason.