Increased capacity in an MS protection ring using WDM technique and OADM: the `coloured section´ ring

The authors present a new method for upgrading the capacity of an existing SDH ring without having to either install additional rings or use higher bit rate equipment. The optimisation is obtained by assigning a specific wavelength to each multiplex section (MS) of the SDH ring. With wavelength routing new possibilities are provided in the network for addressing each node separately, with an order independent of the physical location