Provided is a network switching technique for establishing a high-reliability path, with consideration of the time axis, in response to a request for a connection from a user. A server apparatus (5) includes a connection-request receiving means (201), a resource managing means (202) for managing the resources of a core network (2), a route calculating means (203) for calculating the route of an operation-side path (61) and the route of an auxiliary-side path (63) in response to a request for a connection from a user, a high-reliability-path requesting means (204) for requesting that an originator node apparatus (10) establish the operating-side path (61), a response receiving means (205) for receiving a response to a request for the operating-side path (61), an operating-side path establishment signal receiving means (206), an auxiliary-side path establishment signal receiving means (207) for receiving the path switched by the originator node apparatus (10), a path information updating means (208), and a storage means (209).