ABSTRACT
Optical network has carried more than 80% telecommunication traffic. In order to efficiently manage network resources and provide adequate quality of service (QoS), optical network has developed rapidly in recent years, it has experienced from SDH/SONET to OTN, from OTN to IP over WDM, to MPLS, to GMPLS, to ASON, to WSON. New communication services (e.g., VOIP, IPTV, VOD, cloud computing, and very high speed Internet access) and high-speed bandwidth requirements need more intelligent and higher speed optical network. It has evolved into a multi-layer, multi-domain intelligent optical network. The transmission rate of optical network increases rapidly, it is Mbps in 1985, now it can reach Tbps. With the rapid development of optical network, optical network need to face new challenges: the coexisting of multi-granularity services, the sharing conflicts of network resource by a large number of routing information and signaling, etc. Therefore, there is a need to have corresponding multi-layer multi-domain routing technology so as to achieve rapid intelligent automatic optical switching.
