Virtual-Channel Flow Control and Buffering - Microarchitecture of Network-on-Chip Routers - page 105

6.5 Take-Away Points

Virtual channels is analogous to adding lanes in a street network although imple-
mented virtually and allowing flits that belong to different lanes to appear on the
physical link in a time-multiplexed manner. The existence of multiple VCs requires
the enhancement of the flow control mechanism and the associated buffering
architectures. Sharing the buffers across different VCs, when applied with care, can
increase buffer utilization and reduce the overall cost of supporting multiple VCs.
The latency in the forward and the backward propagation of the flow control signals
increases the minimum buffering requirements for supporting full transmission
throughput and complicates buffer sharing.