nce the packet network. On the other hand, extensive use of protection means devoting a main part of the CAPEX needed to build the network to built a back-up capacity. Survivability strategies are also implemented at higher layer with respect to transport, at the MPLS or Ethernet layer, for example. Due to the poor interworking between transport and upper layers, Convergent Network Management and Control Plane potential coordination between survivability strategies at different layers is generally not fully exploited at present days, creating sometimes quite inefficient situations. An example is provided by the configuration in which dedicated optical channel pro- tection is applied at the OTN transport layer and restoration with prereserved back-up is applied at the MPLS layer. To implement restoration, for each LSP the MPLS asks the OTN layer to provide a back-up capacity, which is prereserved SO as to be associated to one or more LSPs once a failure happens. On the OTN side, this request is not different from any request of MPLS layer and the provided capacity will be protected at the OTN layer. Thus, in case of failure, for each failed LSP, the OTN will devote three times the back-up capacity: one time for OTN protec- tion, one time to provide capacity for MPLS restoration, and one time to protect the capac- ity provided for MPLS restoration. The introduction of a convergent control plane is expected to improve the network sur- vivability exploiting possible interlayer coordination while decreasing the cost of the back- up equipment. In this section, we will use the methods we have introduced in the previous section to analyze the design and performances of different multilayer and single layer survivability strategies applicable in GMPLS networks. In particular, we will analyze the overlay GMPLS model, SO that no pure LSR node can exist, since nodes of the Layer 2 can exchange information with layer one OXCs only through the UNI interface and not through the NNI. The OXC will be considered opaque SO that ele