|The price of memory has decreased to the point where it is now possible to maintain flow state at the input port rather than trying to control flows at the output queue.
Larry Roberts as quoted in Jim Duffy’s article ‘Net pioneer Roberts touts ‘Fast Flow Routing’
Larry Roberts is one of the designers and developers of the ARPANET. He also founded Anagran, a company that sells the Anagran FR-1000 Flow Router. The list price for the FR-1000 is $70,000.
According to the Anagran website:
Conventional wisdom for the past 40 years had concluded that while potentially enormously powerful, flow technology was too expensive to implement in a commercial product due to the amount of memory required to maintain state information on every flow. However, the steep and rapid decline in memory cost over the past decade has actually made keeping flow state virtually insignificant from a cost standpoint. In fact, flow technology is not just feasible, but is now an extremely cost-effective and efficient way to optimize flows.
Had to look it up: A flow is a single meaningful end-to-end activity over the network.