STM-64 and OC-192 are widely deployed in today’s networks. While great care is devoted to warrant a very high quality of transport, in the real world of day- to-day installation, commissioning and maintenance activities things are not always running smooth. To this effect, several important tests are always carried out in order to assess the good behaviour of these networks before turn-up. Similarly, when the network has been turned on, it is paramount to keep monitoring the network health at ph