Controller Placement for Fast Failover in the Split Architecture

• US 20130028073A1
• Filed: 09/19/2011
• Published: 01/31/2013
• Est. Priority Date: 07/29/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Tatipamula, Mallik, Beheshti-Zavareh, Neda, Zhang, Ying
• Granted Patent: US 8,804,490 B2
• Time in Patent Office: Days
• US Class Current: 370/218
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 41/122 of virtualised topologies, e.g. software-defined networks [SDN] or network function virtualisation [NFV]
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/037 Routes obligatorily traversing service-related nodes
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/48 Routing tree calculation

Abstract

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. 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

Claims

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 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 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 link and switch failure protection within the split architecture network for a potential controller placement at each node; and

selecting the network element corresponding to the node with a best protection metric to be the controller for the split architecture network.

2. The method of claim 1, wherein traversing the set of nodes to calculate the protection metric further comprises the step of:

calculating a routing tree for each node with the node at a roo of h outing tree.

5. The method of claim 1, wherein traversing the set of nodes to calculate the protection metric further comprises the step of

summing all node weights in each routing tree to obtain the protection metric for each node in the split architecture network.

6. The method of claim 1, wherein traversing the set of nodes to calculate the protection metric further comprises the step of:

sorting the set of nodes in descending order based on a number of links to neighbor nodes for each node.

7. The method of claim 6, wherein traversing the set of nodes to calculate the protection metric further comprises the step of:

determining a number of protected neighbor nodes with a connection to other nodes.

8. The method of claim 7, wherein selecting the network element corresponding to the node with a best protection metric to be the controller for the split architecture network comprises the step of:

selecting a node with a largest number of protected neighbor nodes to be the controller.

3. The method of claim 3, wherein traversing the set of nodes to calculate the protection metric further comprises the steps of:

determining a number of downstream nodes in the routing tree for each node in the routing tree; and

setting the number of downstream nodes as an initial weight in the protection metric for each node in the routing tree.

4. The method of claim 3, wherein traversing the set of nodes to calculate the protection metric further comprises the step of:

determining a link protection weight for each node in the routing tree as a number of protected links to downstream nodes in the routing tree;

determining an upstream node protection weight for each node in the routing tree as a number of protected upstream links to the controller; and

multiplying the initial weight by the link protection weight or the link protection weight and the upstream node protection weight to obtain a weight for each node in the routing tree.

9. A network with a split architecture where control plane components of the split architecture network are executed by the set of controllers 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:

a set of network elements interconnected by a set of communication links, each network element in the set of network elements executing a switch that is controlled by and in communication with the controller; and

the controller executed by one of the set of network elements, wherein a position of the network element in the first set of network elements within the split architecture network provides an optimized number of protected links between the controller and each of the network elements in the first set of network elements, the optimized number corresponding to a highest protection metric for the network element in the first set of network elements, wherein the protection metric measures resilience of the split architecture network as a degree of link and switch failure protection within the split architecture network.

10. The network of claim 9, wherein the first set of network elements form a data plane of an evolved packet core (EPC) in a long term evolution (LTE) network, and the controller provides a control plane of the EPC in the LTE network.

11. The network of claim 9, wherein the first set of network elements form a set of data planes for a plurality of cellular network technologies, and the controller provides a control plane for each of the plurality of cellular network technologies.