On the experimentation of the novel GCMR multicast routing in a large-scale testbed

Originally defined in the 90s, multicast is nowadays (re)gaining interest given the increasing popularity of multimedia streaming/content traffic and the explosion of cloud services. In fact, multicast yields bandwidth savings complementing cached content distribution techniques and its potential benefits have been verified by studies several times since then (see e.g. [1]). By multicast routing, we refer to a distributed algorithm that, given a group identifier, allows any node to route multicast traffic to a group of destination nodes, usually called multicast group. To enable one-to-many traffic distribution, the multicast routing protocol configures the involved routers to build a (logical) delivery tree between the source and the multicast group, commonly referred to as the Multicast Distribution Tree (MDT). Nevertheless, the scaling problems faced in the 90s still remain mostly unaddressed and worst-case projections predict indeed that routing engines could have to process and maintain in the order of 1 million active routes within the next 5 years [2].