Do any of the people who've worked with some of the IPTV delivery services
mentioned here know if their live TV services can be handled via Multicast?
Off-list replies are fine; will summarize if anyone else cares.
Cheers,
-- jra
I know that Bell Canada uses the Microsoft MediaRoom IPTV servers and
they support multicast. The delivery network is somewhat separate from
the data network. At the DSLAM, they travel as separate VLANs to the
customer. Bell Canada hasn't provided technical answers to exactly where
IPTV and data start to share transmission facilities (from a tariff
point of view, they do not wish to admit that both share trunk lines to
COs).
You may also wish to look at the Australian NBN.
http://www.nbnco.com.au/multicast
Somewhere on their web site, they have the specs of the L2 service with
regards to voice and data.
Recently, they announced a trial for multicast IPTV retailer over the
wholesale NBN.
Nearly all IPTV is multicast via group joins. That is how they limit access to content. It is all technically live (save for vod) as it is down linked from a source and fed into the head end. A lot of cable providers do multi cast over coax now as well. Check out cable labs if you haven't, they have some neat stuff they discuss.
However you get your video feed you can encode it as ip and feed it out to
your shelves as IGMP streams. This is the "normal" way to handle linear
programming.
More accurately you'll do MPEG 4 streams controlled by IGMP.
Yes.
Most live IPTV is delivered across multicast*. There are a few gotchas.
MMR uses a unicast fill for instant channel change (configurable bandwidth
ammounts, etc) on top of Multicast. Some other middleware may have similar
methods to accomplish this.
Usually at the DSLAM you'll see "hax" to forward IGMP requests and
multicast ingress to/from a specific VLAN.
Most EFM based DSLAMs will segregate this all the way down to the CPE, and
let the CPE handle differentiating the joins on the particular VLANs.
Sometimes it's handled inside the DSLAM, but usually it's all configurable.
Handling live TV unicast is definitely possible but brings up another set
of challenges across the SP network towards the DSLAM/Agg point. Mainly
reproduction of the same content * subscriber count, so your bandwidth
towards a given DSLAM/Agg point grows with every subscriber. Low
penetration count of IPTV, this can be less bandwidth, as IPTV penetration
grows this could be several times the multicast bandwidth.
Usually most channel lineups are 1gbps->2.5gbps of multicast bandwidth,
depending on channel bitrates, amount of content, etc, etc..
MMR == Microsoft Mediaroom
Note that in Canada, because incumbents refuse access to their multicast
enabled infrastructure, some of the newer (small) IPTV providers use
unicast via the GAS/TPIA networks to deliver to individual customers.
Obviously, they do not get bandwidth savings when many customers watch
the same program, but they are at least able to offer some TV service
which allows them to bundle Internet and TV instead of forcing their
internet customers to subscribe to the cable service.
Bell Canada (telco) does not allow indie ISPs to resell Bell Canada's
IPTV service, nor does Bell canada accept to sell it to end users who
are not subscribed to ell Canada's own internet service. So for folks
on DSL based indie ISPs, , because the telco refuses to sell them IPTV
services, the indie smaller IPTV providers provide an alternative.
Note that in Canada, there are geographical restrictions to "BDU"
(broadcast distribution undertaking). So an IPTV provider who is alower
to distributre only in a certan region of Ontario for instance will to
geolocate the subscriber before allowing access to the TV data. This
geolocation is done by a transaction with the ISP to confirm the
address/city of the subscriber falls within the allowed serving area.
So the IPTV supplier needs to setup with each ISP to allow for this to
happen (and sign contracts, billing etc etc).
OTT providers who obtain "network" distribution risght are not
regulated. But Broadcast distribution are highly regulated in Canada.