Ethernet machines; in this way the ADM performs switching operations both at layer 1 and 2 and realizes through its embedded capability the adaptation function between the two layers. The evolution of SONET machines, however, has not stopped to MSPP. As a matter of fact, below the next generation SONET rings, almost every time the network is built on DWDM transmission. On the ground of this fact, a new generation of equipment was born integrating together DWDM and MSPP that is generally called multi service transport platform (MSTP). It is not yet clear if MSTP systems will have success on the market, since there is quite a discussion both among carriers and among equipment vendors on their real effectiveness. Switching Systems: Architecture and Performances On one side, MSTP ADMs promise a sizeable reduction of the CAPEX needed to deploy the network due to the synergies present in the integration of many functionalities on the same platform. Just to make an example, building the equipment of a network node by using a DWDM terminal with a local OADM to drop a few channels, a separated SONET ADM for each dropped channel to perform grooming and path routing at low speed, and an Ethernet switch requires three different controllers, three different cooling systems, and so on, while an MSTP ADM has only one processor, attaining also the further advantage to be naturally controlled by one management system, while three differ- ent pieces of equipment have to be separately integrated under the carrier network manager. On the other side, two elements seem to attenuate if not cancel the advantage of integra- tion of different function in a single equipment. The first was already mentioned discussing opaque OXC with colored line interfaces. Since it is in practice impossible to generate a WDM channel with a WDM interface of a vendor and propagate it through the line (amplifiers and optical equalizers like flattening filters and DCF modules) designed by another vendor, integrating the DWDM into the switching equipment (an M