Kawaihiko and the third-quartile day

The Kawaihiko network, linking the New Zealand universities to the Internet , pioneered traffic measurement as a tool for network management and cost r ecovery. Its history and its use of the Real-Time Traffic Flow Measurement architecture to measure its traffic are described. The Kawaihiko members wa nted a "measured bandwidth" metric which would be a good indicator of the b andwidth required to carry each site's traffic. Kawaihiko developed such a metric - the Third-Quartile Day - based on a daily usage profile or Third-Q uartile Profile. 3QP and 3QD are described in detail, and illustrated with typical plots from several of the Kawaihiko sites. The Kawaihiko members fo und 3QD to be an effective bandwidth measure, and 3QP a useful traffic mana gement tool.