ough the element manager. It demultiplexes the incoming line Telecommunication Networks Regeneration section SONET section Multiplex section SONET line e.g., STM16 e.g., OC-48 SDH path Sonet path e.g., VC-3 e.g., VT-6 SDH nomenclature SONET nomenclature FIGURE 3.28 Sections in a trail through an SDH/SONET network. DXC, digital cross connect; TE, line terminal; REG, regenerator. signal, delivers it to the client the VCs associated to the path ending in its node, multiplexes again all the incoming VCs that are not destined to its node with the client generated VCs and sends it to the output line. Naturally, since all the operations are performed on the digital signal, a TE also performs complete regeneration of the signal. The DXC is a quite complex machine. It has several line inputs and several line outputs and it is also connected with several clients. The DXC function is to route the VCs toward the correct destination; in order to do that while efficiently exploiting the available trans- mission capacity, the DXC operates in the following way. First, the client circuits requests are transformed in VCs, while the signals coming from the input lines are demultiplexed and the STSs are reported via adaptation to the path layer, extracting the contained VCs. All these operations are of course related to a set of performance and correct working controls that are carried out every time a signal transits through an adaptation function to be processed to a different layer. When all the VCs are enucleated, the DXC read on the VCs the final destination and routes each VC toward the corresponding output port. Now it is important to underline differences between the operation of a router and the operation of a DXC. First of all, a router works on statistically multiplexed signal; thus, conflicts can happen between different packets both at the input and at the output ports, thus generating packet loss. A DXC works on deterministic TDM frames that are statically configured by a central management software. This means that al