AbstractA WDM optical layer can provide differentiated services to various upper layer protocols by forming many virtual optical networks (VONs). Polymorphic control of an optical layer in the form of On‐demand‐reconfiguration in some VONs and Self‐reconfiguration in other VONs is proposed. The former is suitable for bursty traffic and short‐lived connections, and the latter is for steady traffic and long‐lived connections. In respect to On‐demand‐reconfiguration, efficient distributed wavelength reservation protocols, and in particular optical burst switching (OBS) protocols supporting bursty traffic (eg. Internet traffic) are described. In respect to Self‐reconfiguration, optimal algorithms to schedule all‐to‐all personalized communications (AAPC) in WDM rings and its exten