Reivindicaciones

C l a i m s 1. Method for operating a network, wherein said network (1 ) includes a plurality of network nodes (5), and wherein traffic flows - real flows - are routed from network node (5) to network node (5) within said network (1 ), c h a r a c t e r i z e d i n the steps of introducing in said network (1 ) a virtual source node (2) and a virtual destination node (3), and creating virtual links between said virtual source node (2) and each of said network nodes (5) as well as between each of said network nodes (5) and said virtual destination node (3), introducing a number k of virtual flows originating at said virtual source node (2) and terminating at said virtual destination node (3) in such a way that a network node (5) can either route a virtual flow or any real flow, formulating an IP (Integer Programming) problem that aims at maximizing the number of routed flows - real flows and virtual flows - and solving said problem wherein throughput demands are taken into account, and those network nodes (5) which are occupied with routing a virtual flow are powered down. 2. Method according to claim 1 , wherein communication links between network nodes (5) of said network (1 ) are combined to link groups in such a way that communication links belonging to the same link group share at least one common resource. 3. Method according to claim 1 or 2, wherein the capacity of said virtual links is set equal to the product of the maximum number of interfaces n<max> the involved network node (5) possesses and the largest link group capacity C<max>. 4. Method according to any of claims 1 to 3, wherein the throughput requirement of each of said virtual flows is set to n<max>C<max>. 5. Method according to any of claims 1 to 4, wherein a constraint on each of said network nodes (5) is introduced such that the throughput that traverses a network node (5) cannot exceed n<max>C<max>. 6. Method according to any of claims 1 to 5, wherein said IP problem is solved by using relaxation techniques which aim at first solving the corresponding ILP (Integer Linear Programming) problem. 7. Method according to any of claims 1 to 6, wherein said IP problem is solved by applying an iterative algorithm in which the number of inactive network nodes (5) is stepwise increased. 8. Method according to any of claims 1 to 7, wherein said IP problem is solved considering the option of partially powering down network nodes (5).