stanislav shalunov: linkknot: IP performance metrics

A wide variety of metrics is used to categorize IP performance. Simple things that measure steady-state networks are loss, delay, and jitter. Then there's network capacity (a.k.a. bandwidth). All of these are orthogonal.

Further, some use performance metrics that are quite hard to observe externally, such as average queue lengths, percentage of tail-dropped packets, etc.

Ability to unambiguously characterize IP performance in standard terms is important for QoS deployment. IETF IPPM working group develops standards for both performance metrics and methods of their measurement.