Connection-oriented multicasting in wormhole-switched networks on chip

Network-on-Chip (NoC) proposes networks to replace buses as a scalable global communication interconnect for future SoC designs. However, a bus is very efficient in broadcasting. As the system size scales up to explore the chip capacity, broadcasting in NoCs must be efficiently supported. This paper presents a novel multicast scheme in wormhole-switched NoCs. By this scheme, a multicast procedure consists of establishment, communication and release phase. A multicast group can request to reserve virtual channels during establishment and has priority on arbitration of link bandwidth. This multicasting method has been effectively implemented in a mesh network with dead-lock freedom. Our experiments show that the multicast technique improves throughput, and does not exhibit significant impact on unicast performance in a network with mixed unicast and multicast traffic if the network is not saturated.