Improved Packet Reordering Metrics

This document presents two improved metrics for packet reordering,namely, Reorder Density (RD) and Reorder Buffer-occupancy Density(RBD). A threshold is used to clearly define when a packet isconsidered lost, to bound computational complexity at O(N), and tokeep the memory requirement for evaluation independent of N, where Nis the length of the packet sequence. RD is a comprehensive metricthat captures the characteristics of reordering, while RBD evaluatesthe sequences from the point of view of recovery from reordering.These metrics are simple to compute yet comprehensive in theircharacterization of packet reordering. The measures are robust andorthogonal to packet loss and duplication. This memo providesinformation for the Internet community.