This attribute specifies the throughput importance of the packets when forwarded over VNS connections. In times of congestion the discard priority of a packet is used to determine whether the packet should be discarded to reduce the heavy traffic load. Packets with lower discard priority (numerically higher vdp) are more likely to be discarded than packets with higher discard priority (numerically lower vdp). Discard priority one (vdp 1) should be used for the most important traffic, whereas discard priority three (vdp 3) should be used for the least important traffic.