This records the color (green or yellow) the PDV results in this row apply to, letting an admin distinguish jitter measured on committed-rate traffic from jitter on excess-rate traffic, since yellow traffic experiencing queuing delay under load can show materially worse jitter than green traffic on the same link. An admin checks this to correctly attribute a PDV figure to the right service tier. For example, a much higher PDV on the 'yellow' result than the 'green' result at the same rate would confirm excess traffic is queuing behind committed traffic as intended rather than being treated equally.