tage of having a cheaper equipment architecture would be almost surely overcompensated by the impossibility to exploit competition among suppliers to have lower prices. For this reason, it is difficult that incumbent carriers decide to adopt OXCs that are inte- grated with the transmission system. 7.7.4.2 OXC with an Electronic Switch Fabric The capacity of an OXC switch fabric is impressive, both in terms of switched Gbit/s and in terms of number of channels. A network node of order 4 must host an OXC with at least four incoming WDM and four outgoing WDM. Assuming that all the optical channels are at 10 Gbit/s and that the long- haul systems can accommodate up to 128 channels, the switch matrixes have to accommo- date 512 unidirectional fluxes at 10 Gbit/s, that means about 5 Tbit/s. If the channels would be at 40 Gbit/s, the capacity would be as high as 20 Tbit/s. An OXC designed for large core networks can happen to have even 20 in/out WDM sys- tems with a switch capacity on the order of hundreds of Tbit/s. In this section, we will analyze the case in which the switch fabric is realized by means of an electronic switch. As we have seen in Chapter 6, electronic switching is probably for a long period of time more than competitive with optical switching. The nm technology has allowed power consumption to be greatly reduced and the 22 nm node seems to be not SO far. The electronic solution is also rich of functionalities that can be integrated into the same chips where the switch resides, thus simplifying the design and the management of the switch fabric. There are two main possible architectures for an electronic OXC switch fabric: scaling the signal speed or working with the same signal speed used for transmission. In the first case, the electronic switch matrix is fed by an intermediate speed signal pro- duced by a battery of deserializers placed in front of the switch itself. A deserializer trans- forms a high-speed serial signal into a set of lower speed signals that are present on space distinct lines at t