@alienghic @ohir @Andres4NY @KathyReid Inter-domain multicast. Here be dragons. Hardly any ISP does it properly. The only people who do do it properly are high frequency financial traders and investment banks, or very dedicated academic and community networks. You can pretty much forget about it working properly over ad-hoc nets; that is a very specialist topic. I wrote an OLSR process for mobile/wireless use that CRC Canada took an interest in and left the design open for that, but very 2FC!