Every now and then I stumble upon an elegy lamenting the need to study IP Multicast to pass one or the other certification exam. The history obviously repeats itself; we’ve been dealing with similar problems in the past and one of my favorite examples is Banyan VINES.
If you’ve been working with Cisco routers for more than 15 years, you might still have fond memories of Router Software Configuration (RSC) course, at its time one of the best networking courses. In those prehistoric days, the networks were multi-protocol, running all sorts of things in parallel with IPv4. The week-long RSC course thus covered (at least) the following protocols: IPv4, AppleTalk, Novell IPX, DecNET, XNS, Banyan VINES, CLNP and SNA (I probably forgot one or two). By the third day, everyone (including the instructor) was sick-and-tired of the endless stream of lookalike protocols and ready to skip a section or two.
The Banyan VINES section was the obvious candidate, but I always had exactly one student in the class of 16-20 students that wanted to have it covered, because Banyan VINES configuration was the only reason he attended the RSC course. You see ... although (almost) nobody was using that weird protocol, it was used by a few “obscure” entities, including Coca Cola, Siemens, and US Marine Corps.
IP multicast faces the same problem: almost nobody is using it, but the few people that do need it pretty badly; they range from Service Providers delivering 3-play services to financial institutions delivering live video feeds to trader floors.