The Revised ARPANET Routing Metric

The ARPANBT routing metric wasrevised in July 1987,resulting in substantial performance improvements, especially in terms of user delay and effective network capacity. These revisions only affect the individual link costs (or metrics) on which the PSN (packet switching node) basesits routing decisions. They do not affect the SPF (“shortest path Erst”) algorithm employed to compute routes (installed in May 1979). The previous link metric was packet delay averaged over a ten second interval, which performed effectively under light-to-moderate traffic conditions. However, in heavily loaded networks it led to routing instabilities and wasted link and processorbandwidth. The revised metric constitutes a move away from the strict delay metric: it acts similar to a delay-based metric under lightly loads and to a capacity-based metric under heavy loads. It will not always result in shortest-delay paths. Since the delay metric produced shortestdelay paths only under conditions of light loa...

• Type: Conference
• Year: 1989
• Where: SIGCOMM
• Authors: A. Khanna, John A. Zinky
• Keywords: Communications, Metric, Metric Produced Shortestdelay, Routing Metric, SIGCOMM 1989