Patent Document ID: 20140321330
Application ID: 14327431
Patent Flag: 0

Claim One:
1. A method implemented by a network topology design system, the network topology design system including a processing device, the method to determine placement of a controller within a network with a split architecture where control plane components of the split architecture network are executed by a controller and the control plane components are separate from data plane components of the split architecture network, wherein the placement of the controller is selected to minimize disruption of the split architecture network caused by a link failure, a switch failure or a connectivity loss between the controller and the data plane components, the method comprising the steps of: graphing, by the processing device, a topology of the split architecture network, with links in the split architecture network represented as a set of edges in a graph and network elements in the split architecture network represented as a set of nodes; traversing, by the processing device, the set of nodes within the graph to calculate a protection metric for each node, wherein the protection metric measures resilience of the split architecture network as a degree of node failure protection within the split architecture network for a potential controller placement, the degree of node failure protection determining a subset of protected nodes in the set of nodes, where a protected node in the subset of protected nodes can redirect control traffic over a tunnel to an intermediate node in the graph that is not downstream of the protected node, and where the tunnel traverses at least one downstream node of the protected node; and selecting, by the processing device, the network element corresponding to the node with a best protection metric to be the controller for the split architecture network.