nce factor RF relative to node failure is also reported. This new factor is defined in line with the definition of RF as (8.45) TABLE 8.12 Resilience Degrees of Various Order for Two Multilayer Survivability Strategies RF indicates the factor relative to full node failure. Convergent Network Management and Control Plane where N is the node number lspn(j) is the total number of GLSPs processed in the absence of any failure by node lsp'(j) is the subset of lsp (j) composed by the GLSPs that are restored by the network survivability procedure after the failure of node j Isp (j) is the subset of lsp (j) that are started and terminated locally in the failed node The term Ispn(j) is added to the numerator of Equation 8.45 SO to obtain a definition that gives one in case of full recovery, since local GLSPs cannot be recovered with any mean if the node fails. 8.5.3.2 QoS-Driven Multilayer Survivability From a survivability point of view, multilayer restoration R-R and multilayer protection- restoration SP-R are completely satisfactory, assuring excellent resilience against a large number of failure events and a very high GLSP survivability. Against this good perfor- mance, the cost to pay in terms of additional equipment to be deployed to provide the required spare capacity is very high. The cost of the network equipment is almost multi- plied by two in the case of R-R and by more than two in the case of SP-R. Sometimes it could be the right choice, due to the fact that the customer is willing to pay a high price to have a nine "9" survivability, it is the case of banks, other business customers like insurance, companies providing network based back-up of strategic data and SO on. In other cases however, this is clearly an excessive target bringing an excessive cost. This consideration, besides the very flexible structure of GMPLS, allowing to character- ize GLSPs with a certain number of different tags, suggest that it should be the customer requirements, summarized in the service level agreement to drive the type of su