SPF is a Cadence Design Systems standard for defining netlist parasitics. DSPF and RSPF are the two forms of SPF; the term SPF itself is sometimes used (or misused) to represent parasitics in general. DSPF and RSPF both represent parasitic information as an RC network. RSPF represents each net as an RC "pi" model, which consists of an equivalent ”near" capacitance at the driver of the net, an equivalent "far" capacitance for the net, and an equivalent resistance connecting these two capacitances. Each net has a single "pi" network for the network, regardless of how many pins are on the net. In addition to the pi network, RSPF causes the PrimeTime tool to calculate an Elmore delay for every pin-to-pin interconnects delay.