Multicast Routing with Dynamic Packet Fragmentation

Networks-on-Chip (NoCs) become a critical design factor as chip multiprocessors (CMPs) and systems on a chip (SoCs) scale up with technology. With fundamental benefits of high bandwidth and scalability in on-chip networks, a newly added multicast capability can further enhance the performance by reducing the network load and facilitate coherence protocols of many-core CMPs [10]. This paper proposes a novel multicast router with dynamic packet fragmentation in on-chip networks. Packet fragmentation is performed to avoid deadlock in blocking situations, releasing the hold of an output virtual channel (VC) and allowing another packet to use the freed VC. From circuit simulation of the design implemented with IBM 90mn technology, the proposed router reduces latency by 38.6% and consumes 9% less energy than a unicast baseline router at the baseline saturation.