and thermal design and for net- work element control architecture). The cards composing generic switching systems can be classified in four categories: 1. Interface cards 2. Switch fabric cards 3. Processing cards 4. Control and service cards Interface cards have the role to connect the switching network element with the surround- ing network both on the line side (line cards) and on the client side (client cards). Generally, the interface cards have an optical interface SO that the signal is transmitted or received from a nearby equipment using fiber optics patch cords. The switch fabric cards host the redundant switch fabric. Even if a single card would be sufficient, due to the requirements of switch fabric protection, the two switch fabrics have to be hosted on different switch fabric cards that have to be connected through the platform. The processing cards are the card containing hardware dedicated processors perform- ing the operations needed to route the packet. This operation has to be performed millions of times a second; thus, in high-performance routers and switches several such cards host- ing dedicated hardware are needed. The control cards are all the cards devoted either to configure the network element (as the rack processor), or to terminate and regenerate the signal on the control and Switching Systems: Architecture and Performances management plane, thus running either procedure forced by the central operation system or automatic protocols. Examples of the control cards are the rack controller and the service channel termination card in equipment having a few interfaces of the WDM type. The two elements differentiating the platform of switching network elements are the power consumption and the type of backplane that is needed. Regarding power consumption, the power needed to an electronic switch fabric card is in general much higher with respect, for example, to the power needed to a dense wave- length division multiplexing (DWDM) transponder. Talking about Clos switch fabrics, we have consid