On Tue, 31 Jul 2018 21:28:31 +0000 Sean Donelan <sean@donelan.com> wrote:

I did all the google searches, check all the usual CAIDA and ISP sites. IP Multicast is used on private enterprise networks, and some ISPs use it for some closed services.

More anecdotal evidence. Probably the best place to know what is going on with multicast is on the mboned list (yea that still exists): <https://mailarchive.ietf.org/arch/browse/mboned/> Second best might be the Internet2 community where a number of institutions that have always had it might still have it turned on. Though there has been only one post in all of 2018 on their list if that tells you anything. There is almost no public multicast monitoring anymore. Practically all dead. You could poke around the I2 router proxies and see what is happening on some of the last of the remaining IP multicast-enabled Internet (hint, mostly noise from odd devices that have strayed outside the local institution): show multicast routes show pim join ... I keep hearing about some research project in the deep blue sea that uses it. You might find a small amount of it out there, but I'd bet overall its usage is teeny tiny and limited to a shrinking number of networks. Turned off interdomain multicast when I returned here in 2016. John