e new paradigm, where unpre- dictable traffic is routed on an automatically managed network. 8.4.1 Detailed Example: Design Target and Issues Since the design problem for an ASON/GMPLS network is really complex comprising a great number of elements, in this section, we will carry out in detail a simple example, in order to clarify some of the main issues in designing such a network. We will not be SO formal in defining performance evaluation parameters and design procedures, and a more precise discussion of these points will be carried out in Sections 8.5 and 8.6. The main task of this section is to give a feeling of the main aspects and of the complexity of the problem working on a very simple example. The network we will consider in this example is a multilayer network, like the ASON/ GMPLS networks. We will assume for simplicity that a DWDM transport layer based on electrical core OXCs has a single client layer, an IP network. We will also assume that the IP network is composed of LSRs and managed by an MPLS control plane, and that the over- lay model defined by the GMPLS standard is implemented for the overall control plane. This means that the general network node is equipped as in Figure 8.19, with an LSR con- nected to an electrical core OXC via a UNI interface. The starting point is the physical topology constituted by buildings where it is possible to place network nodes and fiber cables as represented in Figure 8.20. At the beginning, we will assume that the traffic to be routed through the network is known and that the design consists of deploying equipment on the given topology in an optimized way to support the traffic. In a second step, we will see what happens if the traf- fic is not known, but it is known only as traffic statistics. To simplify the approach, we will assume that all the MPLS layer LSPs to be set-up have the same capacity and that we will set equal to one to normalize transmission capacities. Telecommunication Networks FIGURE 8.19 Scheme of the two layer node considered in the examp