quality:corruption
Invention and development

In the late 1950s, the US Air Force established a wide area network for the Semi-Automatic Ground Environment (SAGE) radar defense system. Recognizing vulnerabilities in this network, the Air Force sought a system that might survive a nuclear attack to enable a response, thus diminishing the attractiveness of the first strike advantage by enemies (see Mutual assured destruction). In the early 1960s, Baran invented the concept of distributed adaptive message block switching in support of the Air Force initiative. The concept was first presented to the Air Force in the summer of 1961 as briefing B-265, later published as RAND report P-2626 in 1962, and finally in report RM 3420 in 1964. The reports describe a general architecture for a large-scale, distributed, survivable communications network. The proposal was composed of three key ideas: use of a decentralized network with multiple paths between any two points; dividing user messages into message blocks; and delivery of these messages by store and forward switching. Baran's network design was focused on digital communication of voice messages using hardware switches that were low-cost electronics. The ideas were not entirely original to Baran and the task to design a store and forward type of network was formulated by Baran's boss at RAND.