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Why is so much of IPv4 allocated to multicast when it cannot be used by the public at large ? (lemmy.ml)
submitted 1 year ago* by to c/asklemmy@lemmy.ml
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I found the multicast registery here.

https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml

I already knew that addresses between 224.0.0.1 and 239.255.255.255 are reserved by multicast.

Obviously multicast could be immensely useful if used by the general public, it would obsolete much of facebook, youtube, nearly all CDNs (content delivery networks), would kill cloudflare and company's business model and just re-arrange the internet with far reaching social implication.

So, why hasn't all these multicast addresses been converted in usable private IPv4 unicast address space ?

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[โ€“] 0 points 1 year ago (1 child)

Assuming multicast worked across the internet, it's not going to work in practice. Multicast works by sending a packet and fanning it out to all receivers.

It works with broadcast TV like IPTV because everybody is watching the same few set of channels at the same time, but on YouTube I can watch any video at any time. How does a mythical Transmitter know what video packets to send when? Are they on loop? Are clients receiving packets for videos they don't care about?

You might be interested in PeerTube which uses unicast peer to peer to distribute videos in a way that works.

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  • [โ€“] [S] -3 points 1 year ago

    This minor technical difficulties could easily be avoided, they not at all a problem inside the CDN network, once your past the gatekeepers just look at twitch, it's a piece of cake to make it work even though the engineers will disagree.

    The only technical limitation they had to bypass, was every little ISP being it's own little bridge troll about it and the CDN sidestep this entirely by running a whole parrallel network.

    And now, there's all that CDN sunk cost making sure we'll never EVER have working multicast on the internet, and they'll have all the make believe excuses to pretend we can't ,even though, it's basically the same as unicast routing with extra steps....

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