Control apparatus, control method and program for allocating virtual networks for providing network services to a physical network

1 . A control apparatus configured to allocate virtual networks for providing network services to a physical network, the control apparatus comprising:

circuity configured to:

select, from virtual servers that are allocated to nodes, second virtual servers as candidates that are to be reallocated to the nodes, based on changes in a cost for the nodes that are included in the physical network, upon occurrence of a condition in which the virtual networks are allocated to the physical network,

determine the changes in the cost for the nodes,

rank the nodes based at least on a descending order of the changes in the cost for the nodes,

set priorities associated with reallocation of the virtual servers allocated to the nodes, based on the ranked nodes,

select one or more of the second virtual servers as candidates to be reallocated to given nodes, in descending order of the set priorities, and

allocate a second virtual network including a specific virtual server to the physical network based on information related to the physical network.

2 . The control apparatus according to claim 1 , wherein the circuitry is configured to select, from the virtual servers, a predetermined number or a predetermined percentage of the second virtual servers.

3 . The control apparatus according to claim 1 , wherein the circuitry is configured to allocate a second virtual network of the virtual networks to the physical network, based on information related to the physical network, the second virtual network including a specific virtual server among the second virtual servers.

4 . The control apparatus according to claim 3 , wherein the circuitry is configured to select, from the virtual servers, a predetermined number or a predetermined percentage of the second virtual servers.

5 . A control method executed by a control apparatus that allocates virtual networks for providing network services to a physical network, the control method comprising:

selecting, from virtual servers that are allocated to nodes, second virtual servers as candidates that are to be reallocated to the nodes, based on changes in a cost for the nodes that are included in the physical network, upon occurrence of a condition in which the virtual networks are allocated to the physical network,

determining the changes in the cost for the nodes,

ranking the nodes in descending order of the changes in the cost for the nodes,

setting priorities associated with reallocation of the virtual servers allocated to the nodes, based on the ranked nodes,

selecting one or more of the second virtual servers as candidates to be reallocated to given nodes, in descending order of the set priorities, and

allocating a second virtual network including a specific virtual server to the physical network based on information related to the physical network.

6 . A non-transitory computer readable medium storing a program which causes a computer to execute the control method of claim 5 .

7 . A control apparatus configured to allocate virtual networks for providing network services to a physical network, the control apparatus comprising:

circuity configured to:

select, from virtual servers that are allocated to nodes, second virtual servers as candidates that are to be reallocated to the nodes, based on changes in a cost for the nodes that are included in the physical network, upon occurrence of a condition in which the virtual networks are allocated to the physical network,

determine the changes in the cost for the nodes,

rank the nodes in descending order of the changes in the cost for the nodes,

set priorities associated with reallocation of the virtual servers allocated to the nodes, based on the ranked nodes,

select one or more of the second virtual servers as candidates to be reallocated to given nodes, in descending order of the set priorities, and

allocate a second virtual network including a specific virtual server to the physical network based on information related to the physical network,

wherein the information related to the physical network includes at least one of information indicating an outside temperature of each node that is included in the physical network, physical resource information of the physical network, and information indicating a predicted traffic amount of the physical network.