CGM2: Carrier-Grade Minimalism Multicast with Stateless Explicit Path

Group communication is a one-to-many communication pattern that distributes data from one sender to multiple receivers. Multicast as a group communication method is extensively employed in content distribution scenarios, such as IP-based cable TV, live streaming, video conference, data delivery, etc. Since application-layer multicast cannot touch network elements, it suffers from inefficient network utilization. Some existing network-assisted multicast are limited by scalability issues caused by the inability to maintain a sharply increased per-flow state in individual network elements. Moreover, existing network-assisted multicast is unable to meet the newly emerging need, such as load balancing and traffic engineering. This paper presents a novel multicast technique called Carrier-Grade Minimalism Multicast (CGM2). Through a string of bits, the bitmap, nodes are instructed to locally replicate packets and forward them over several interfaces without maintaining a per-flow state. Bitmaps of nodes along the multicast path are encapsulated in the recursive format as a binary in-packet tree for explicit forwarding path.