@Roy but how about the BT Smart hub 2 with the inbuilt disc. The mesh network generated by the discs should pass multicast (one for the future possibly ). The smart hubs can pass multicast but they need to be allowed to do it.
@Roy - I would be amazed if the internals were different but I agree the firmware could well of been. I wasn't saying that people with existing Hubs could suddenly change something and make them pass multicast (although it could be possible), I was simply saying that it was possible from a Hub (albeit one that might have been slightly different) and therefore I would expect the new hub to have this built in otherwise it would be fairly 'un-futureproofed' especially as BT have already proved it can be done (albeit not very well back then but that was a few years ago).
This is where I show my ignorance. Would the Ethernet LAN port allow you connect a client device i.e. STB or is that port only for direct connection to a router (WAN?), would the client get an address ok via the disc Ethernet port?. The main thing we need to know is if multicast can be carried over the disc mesh network straight out the box, I have asked someone and will see if I get an answer (I have a SmartHub 2 but unfortunately not got my hands on one of the discs yet so can't just try it myself - I have been told that in testing a lot of people that had a 3 disc Whole Home Wi-Fi replaced that with a smarthub2 and one disc and got better speed and coverage than the 3 disc whole home solution but I haven't been able to confirm that myself so it does appear at least slightly hopeful at this point).
Going from someone's comments via your link -
The new Smart Hub 2 above is the first to include built-in mesh functionality even if it is proprietary to BT and to use it you need to subscribe to BT Plus to get the mesh disk(s).
I am not certain of the ins and outs but I know there is a split in the SmartHub 2's menu between 2.4/5 and discs wireless, so although they all use the same ssid's and allow you to roam between devices seamlessly I think there is possibly a difference between the Wi-Fi signal output from the router and the 'mesh' network the disks use (even though in use it would appear no different). Which 'could' mean that you could possibly utilise multicast using the disc network and direct connection of the STB to a disc even if you can't direct from the router wireless, I don't really know.
Again you link would seem to bear this theory out -
UPDATE 27th Nov 2018 @ 2:37pm
BT has confirmed that the 2.4GHz band on their SH2 can deliver a peak WiFi speed of 289Mbps, while the same band for their Wi-Fi Discs will do 385Mbps. The Smart Hub 2’s chipset is also based on Broadcom’s 63138, 4366 and 43602 (i.e. slightly newer than the original SH1).
P.S - just thought I can test one part of this out tonight by plugging my AP into my STB and connecting to the SmartHub2 and seeing if it passes the IP channels, if this does work I expect it to be quite poor as before but I wouldn't be surprised if BT locked multicast to the Wi-Fi mesh network and therefore needed you to buy BT Plus if you wanted to use your STB wirelessly (including maybe releasing a combined disc/wireless box in the future that could be sold with a BT Plus bundle).
@Roy Just had this response -
Just tested it .. works perfectly. STB connected to disc, and disc connected via Wifi to SH2
If I don't get an answer about direct wi-fi connection to SH2 I will test it out myself tonight (unless someone else has a SH2 and AP then can check before me). If BT were smart they would work it so it doesn't work with a direct Wi-Fi connection in which case people would have to buy BT Plus total Wi-Fi off them to get a disc and get it to work (maybe bundle it with a multibox subscription). I can see a new box having the disc electronics bundled within it (maybe they will only allow you to 'borrow' the box) and supply a new SH2 as part of the subscription with a one off installation cost, hang on doesn't that remind me of another company lol....