Next Generation Optical Networks: an Operator's Point of View

Classical optical networks are based on fixed WDM transmission links with a point-to-point configuration. The network of incumbent network operators was dominated by the telephony services. The SDH/SONET-layer combining PDH data rates is the most common transmission hierarchy. But new data services like IP, Ethernet and Storage services with data rates incompatible to the SDH data rates penetrate the network. Either dark wavelengths must be provided for provision of these services or the new data rates have to be adapted to the SDH-network by generic framing procedure (GFP). Next generation networks are characterised by a high number of continuously growing different data rates, packet oriented data transmission and a convergence of voice and data to data transmission. A flexible network is required and can be provided by a network based on the Optical Transport Hierarchy (OTH) with new features like tandem connection monitoring (TCM) and forward error correction (FEC). The interfaces between different networks and the interfaces between customer network and transport network must be standardised. New features like flexible provision of the bandwidth are available by an automatically switched network and by deployment of reconfigurable OADM.