and a randomly chosen two-link route is assigned to be the new current nominated alternative route.Thus the chosen route varies to take changing traffic patterns and demands into account. The technique was the subject of Richard Gibbens' doctoral thesis at Cambridge University under Frank Kelly, in collaboration with BT Research, and a British patent was granted in 1985. DAR was implemented in British Telecom's national network in 1996. See also PSTN network topology General Toll Switching Plan Operator Toll Dialing References External links Bibliography: Dynamic Alternative Routing – Frank Kelly, Statistical Laboratory, University of Cambridge Gibbens, R. & Kelly, F.P. & Key, P. (1988) "Dynamic alternative routing - modelling and behaviour", 12th International Teletraffic Congress, Turin. Via ResearchGate. Teletraffic Routing Telephony