The Distance Domain implementation in the Vector Network Analyzer is trace based, which makes it very flexible to use. Each of the four traces in the instrument can be configured independently and can be in the frequency or distance domain. Each trace can also be configured to represent any of the S‑parameters. The Vector Network Analyzer (as an example) can view S11 in the frequency domain using traces.

With the ability to transform any S‑parameter, one question that arises is whether the time or distance that is plotted represents a one‑way or a round‑trip propagation. The one‑way propagation represents the transmission (or 2‑port) measurement, in which the signal is transmitted from one port, propagates through the device under test, and is received on the second port. One‑way propagation occurs when transforming S21.

The round‑trip propagation represents a reflection (1‑port) measurement, in which the signal is transmitted from one port, propagates through the device under test, fully reflects at the end of the device, and is received back at the same port. Round‑trip propagation occurs when transforming S11.

For reflection measurements, the Vector Network Analyzer can handle the two cases of one‑way and round‑trip propagation differently in the Distance domain. In the distance domain, the instrument compensates for the round trip reflection propagation by showing the actual length of the device under test (essentially dividing the distance by 2 for the reflection measurements). This compensation renders the distance reflection measurement as a One-Way measurement in terms of the distance value that is reported.