[ih] IPv8...

[Jack Haverty]

Can anyone summarize the history of the *use* of "multicast" in The 
Internet?  I know the various protocols and such are probably well 
described in publications such as RFCs and research reports, but I'm 
wondering about the historical timeline of the actual implementation and 
use of multicast in the Internet we have all used for years or decades now.

For example, I remember the "Mbone" which was used for lots of 
experimentation in the 1980s.     IIRC, Mbone had some kind of support 
for multicast, and required that routers along the path you were using 
through the Internet had to have implemented the protocols and 
algorithms for the multicast mechanisms of the time. This affected 
activities such as the various projects experimenting with interactive 
voice over the Internet in the 1980s.   The Mbone was in effect a subset 
of The Internet.

Almost 50 years later, it's pretty common for people to be using the 
Internet in ways that would seem to benefit from use of some kind of 
modern "multicast" scheme.  A typical example would be teleconferencing, 
using Zoom, Meet, Facetime, or any of the other similar systems.   I use 
such things frequently; you probably do too.

None of those systems seem to be "interoperable", i.e., able to hold 
conferences where different participants use different companies' 
technology to participate in a single conference.  Do they actually use 
the standards for multicast defined in RFCs?

Does the "Mbone" still exist as a subset of The Internet?  Did it grow 
and evolve over time to become part of today's ubiquitous Internet 
infrastructure or did it just disappear?

I replaced my home routers last year.  The old routers, bought a few 
years ago, still work but are sitting on a shelf, and I just got a 
notice from the manufacturer that they are now considered obsolete.  But 
I don't remember that either the new ones or old ones promoted 
themselves as "Supports Multicast!!" or anything like that.  I also 
don't remember any of the teleconferencing schemes saying anything like 
"Requires Multicast Routers!!".

So it's hard to tell if any multicast technology is actually needed, or 
even present, or used at all in The Internet today.

Perhaps multicast mechanisms are just no longer needed?  With the planet 
being increasingly woven into a spider's nightmare blanket of fiber, and 
also being encapsulated by tens of thousands of satellites weaving 
complex webs of radio and laser beams, does efficiency matter as much as 
we worried about in the early days of The Internet?

What's the history of the *use* of multicast as the Internet has grown 
and changed over time?

/Jack Haverty

On 4/21/26 08:46, John Day via Internet-history wrote:
> Thanks for the correction.
>
> Not terribly precise, but I wouldn’t expect that.
> I presume there then has to be some method for notifying stations and links that they should be willing? Seems to be an unnecessary complication. In most multicast proposals/implementations I have seen, an application requests to join a service that uses multicast, which would seem to make ‘willingness’ moot.
>
> (Applications shouldn’t have to specifically request multicast. The provider determines whether to simply send n copies or use multicast. It is the provide that benefits, not the application.)
>
> Thanks again,
> John
>
>> On Apr 21, 2026, at 11:31, Craig Partridge <craig at tereschau.net> wrote:
>>
>>
>>
>> On Tue, Apr 21, 2026 at 8:58 AM John Day via Internet-history <internet-history at elists.isoc.org <mailto:internet-history at elists.isoc.org>> wrote:
>>> Let me try to provide some other definitions of multicast and anycast that will either help or confuse things.
>>>
>>> First the definition of multicast in the Internet is patterned after multicast in Ethernet. That definition assumes that all stations see all packets, which implies flooding. This is what happens in Ethernet so it is quite natural and works well. However, it isn’t so useful for general networks, where one would like to avoid flooding. Perhaps a better more abstract definition would be:
>>> (I hesitate to call it a multicast *address* even though it is taken from the IP address space because an address is location-dependent and route-independent. That doesn’t really apply to multicast in general.)
>> You clearly don't understand Deering's contribution to multicast.  He took the semantics of Ethernet multicast and generalized it to an Internet such that "all stations see all packets" but rather only those stations and links willing to receive/carry the multicast address (or, if you wish, a group of multicast addresses of which the target multicast address is one) see the packet.
>>
>> This simplification also applies to anycast in an Internet context.
>>
>> Craig
>>
>> --
>> *****
>> Craig Partridge's email account for professional society activities and mailing lists.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature.asc
Type: application/pgp-signature
Size: 665 bytes
Desc: OpenPGP digital signature
URL: <http://elists.isoc.org/pipermail/internet-history/attachments/20260421/8009494e/attachment-0001.asc>