[ih] IPv8...

[Bill Nowicki]

 Thanks for the set-up! Indeed, the Distributed System Research Hroup at Stanford under Kieth Lantz and Dave Cheriton did a bunch of related work on the left coast. Steve Deering was part of it (came from Canada like Cheriton, eh? so we had "rooters"). Other work like that by Ross Finlayson and Jeff Mogul to name a few (e.g. reverse ARP, I think) were part of that group. Although the V system was probably the test bad, the Deering architecture was quite general. IP multicast did not require the V System, nor did the V System strictly need multicast. For example, Tektronix came out with a very early professional video recorder for live TV that used the V System as am embedded real-time OS. 
The wide-area mbone was used for various experimental real-time audio and video events. Within SGI in the early 1990s we had our own corporate mbone too, used to multicast radio stations and what I called SGI-TV, a live video feed of company meetings that could be viewed by thousands of employees in various campuses around the world. The problem is that any kind of chain-reaction phenomenon can easily be an unstable equilibrium. Once there is any kind of loop, troubleshooting becomes almost impossible. The demise came with network address translation (NAT) HTTP relays. Essentially every protocol in the past 20 years or so above the lowest layers, must be based on HTTP(S) in order to get through a NAT. HTTP is inherently unicast. It did not help that the network providers were selling bandwidth, and the software, cloud and content delivery vendors were selling capacity, so they got much higher revenues from replicated unicast, with only a few big users such as Netflix doing tricks with redundant server load-sharing.
Bill


    On Tuesday, April 21, 2026 at 11:24:27 AM PDT, Greg Skinner <gregskinner0 at icloud.com> wrote:  
 
 I don’t have a summary, but one use was within the V operating system, developed by David Cheriton’s research group at Stanford.  Bill Nowicki (copied, a member of this list) did distributed graphics research on that system. [1]
--gregbo
[1] https://bitsavers.org/pdf/stanford/v-system/nowicki_CSL-85-282_VGTS.pdf


On Apr 21, 2026, at 10:20 AM, Jack Haverty via Internet-history <internet-history at elists.isoc.org> wrote:
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