It is the aim of the present invention to provide a method and a system for reducing to the minimum the network bandwidth allocation for the protected routes of GBW-services. This aims are achieved by a method and a system for minimizing bandwidth allocation for alternative routes within a network, comprising the steps of: a) providing a management system for managing the routes of services within said network; b) providing a plurality of guaranteed bandwidth services, hereafter referred as GBW-services; c) assigning to each GBW-service a traffic class, hereafter referred as TC; d) calculating for each GBW-service belonging to a protected TC an active route and at least one alternative route; the active route being the planned route in case of absence of a respective network failure and the alternative route being the route which guarantees that, in case of a network failure with respect to the active route, said GBW-service is protected elsewhere by protecting the respective network resources; e) providing a first optimized protection mode to be assigned to all the GBW-services belonging to a given protected TC; said first optimized protection mode comprising a first optimization step including the step of reserving bandwidth for each GBW-service only once for each network resource employed by the active and/or the alternative route of each GBW-service.