Abstract: A Delay-tolerant Asynchronous Interface (DANI) is typically used to make the clock domains for reusable silicon intellectual property (IP) cores completely independent of each other. In fact, a DANI-wrapped IP core usually appears to its environment as if it were clockless. This property is necessary to address the variability in data transmission-time between source and destination. This variability is a result of increased lack of predictability in today's leading-edge manufacturing processes. A DANI wrapper can be applied to the IP core that is the source of data to be transmitted or it can be applied to the IP core that is the destination of that data. The transmission time over the route between source and destination may vary more than a single clock period.