Multicasting - what it is, how it works and what your box needs to do to receive it

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I have over the last few days read much misinformation about Multicasting and IPTV, across many different internet forums. So I just wanted to clear a few things up, and dispel a few myths, too -

MULTICAST - What is it?

Multicast is a way of delivering of packets of data over a providers broadband network (typically for, but not exclusive to, IPTV). This is merely a very efficient means of delivering such packets of data over said BB network. I will now refer to these packets of data as IPTV.


Multicast delivery of IPTV only sends one signal around a BB node network for the reception by an unlimited amount of multiple users. This is typically supported by a CDN (a Content Delivery Network). A CDN can be regarded as a second internet network purely for the use of IPTV signals/reception, so ones watching of IPTV will not impact on other users internet usage, and their usage also won't impact on you.



The only piece of equipment a user needs, to receive Multicast IPTV , is to have is a router capable of supporting Multicast signals (which also typically support FTTC/FTTP).

You Box? It needs nothing. No special firmware, no special upgrades and no special hardware, either. All the work for delivering the Multicast signal to your box is all done by your providers CDN BB network and your router only.


Oh yes it can. Well what does everyone think those On Demand/Catch-Up TV player apps are?

Oh, and a bit more info specifically regarding the YouView ISP's -

On both TalkTalk and BT, Multicast IPTV data signals will only be delivered over their fiber networks, and not ADSL or ADSL2.

Now,here's the interesting and speculative bit -

Both TalkTalk and BT have invested considerable amounts of money in a CDN Multicast fiber network to support both a faster internet and the delivery of new YouView content. TalkTalk have/will have spent £400m and BT £2.5b. So... what is to come, in the future of IPTV? Because they sure not using these systems to their full capacity yet....
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Posted 4 years ago

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Piers, Head of Engineering

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Sorry for joining this thread so late, but I think it would be useful to clear up a few things. Some of these points have been mentioned by posters already, so thanks for all your contributions.

- The current Humax box (the hardware) is capable of supporting IP multicast, but it does not yet have all the software needed to connect to TV content streams delivered via IP multicast. This includes all YouView Humax retail boxes, as well as Humax boxes soon to be made available by BT. Software updates will allow these boxes to become multicast enabled in the future - the low level operating system already supports it but there's a lot of other software in the box that needs to become "multicast" aware or even just "IP live channels" aware.

- TalkTalk Huawai boxes can receive live IP channels via multicast on the TalkTalk network, but only via the TalkTalk player right now. Humax boxes are not able to access these channels, and were not able to access them through any of the trails.

- Right now, we're working with manufacturers to add multicast functionality to all YouView boxes, as we want IP channels to be easy to use as possible - so that those folks who don't want to know the technical details don't have to think about IP or multicast at all. This will mean changes to the YouView software, and the Programme Guide, and will take some time to implement. Please be assured that were working as fast as we can on this at the same time as all our other priorities; such as many of the great suggestions listed already on this forum.

Talk Talk have created a page that explains what's possible on their network now. This situation may change when live IP channels and multicast support is rolled out more widely to YouView boxes, but we don't have a exact date for that right now.

I hope this helps, and I'll be happy to answer more questions as they arise (which I'm sure they will!). Thanks for listening.

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Piers, Head of Engineering

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Adrian: RE: your summary "so if I have this right: "... Yes that's about right, but I can't comment about BT's timescales for multicast so best to contact them directly. I've not heard any news that they are enabling multicast for YouView boxes in 2 months time, so there may be some confusion with their existing BT Vision devices.

DM, Anaglypta: yes we'll be enabling unicast delivered channels in the future. We don't support one of the key enabling technologies (HTTP chunked streaming) yet but it is on our roadmap. The BBC are using this for their iPlayer live re-start feature, and there's an interesting article about it here: