Equivalent noise factor dB Switch fabric power consumption (W) Latching switch fabric Fiber modular switch fabric Wavelength modular switch fabric Blocking probability Telecommunication Networks This is an important property of optical equipment. On the other hand, the OXC archi- tecture that we have analyzed has a low degree of modularity. WCs, even if installed in a limited number, are very beneficial to reduce the OXC block- ing probability. 10.3.3 Transport of Control Plane and Management Plane Messages Besides providing the basic switching functionality, the OXCs have also to run control plane protocols and to be able to correctly transmit management plane information to the central management of the network. The main vehicle that the T-OTN uses to build the control and management plane communication infrastructure is the DWDM service chan- nel, a spare wavelength that is out of the bandwidth of the amplifier used by DWDM, and that contains both the OMS and the OTS, both terminated after every hop in the network. However, in a transparent network, it is not easy to transmit the information relative to the optical channel (OCh). This is essentially due to the fact that the header of the OCh, which in the T-OTN coin- cides with the wavelength channel, has to be transmitted in such a way that it is impos- sible to divide it from the data relative to the channel. This is necessary to monitor switching errors via the monitoring at the input and at the output of an OXC of the channel ID and comparing it with the OXC routing table. If an error occurred, for example, for a bad working of a switch matrix in a previously tra- versed OXC, the input port from which the channel is arriving will be different from that reported in the routing table and the error will be detected. If the OCh header is included in the service channel, an error could send the wavelength containing the data in the wrong direction, but the service channel in the right direction. In this condition, sooner or later, the OCh data will arrive at an