Implementing OSPF in split-architecture networks

A network element functioning as one of a plurality of controllers for one of a plurality of areas of a split architecture network, the controller to provide a control plane for the area of the split architecture network where the controller is remote from a plurality of switches providing a data plane for the area of the split architecture network, the controller to facilitate optimized routing across the plurality of areas of the split architecture network by providing limited intra-area link cost data to other controllers of other areas of the split architecture network and to traditional routers of a network including the split architecture network, the limited intra-area link cost data providing costs of each possible shortest path traversal of the area of the controller without providing all internal link cost data, the network element comprising:

• an ingress module configured to receive data over a network;
• an egress module configured to transmit data over the network;
• a network processor coupled to the ingress module and egress module, the network processor configured to execute a set of modules comprising a controller module, a topology learning module, a shortest path calculation module, a neighbor discovery module and a link state management module,
• the topology learning module configured to determine a topology of the area of the controller in the split architecture network including each border switch in the area of the controller, wherein each border switch has at least one external port linking the area of the controller to another area of the network or to a traditional router in the network,
• the controller module configured to provide control plane functionality for the area of controller in the split architecture network,
• the shortest path calculation module configured to identify a shortest path between each border switch in the area of the controller to be shared with neighbor controllers and the traditional routers and to calculate a shortest path tree for the network with the controller as the root of the tree using a link state database,
• the neighbor discovery module configured to identify each neighbor controller and traditional routers in the network using a hello protocol, and
• the link state management module configured to exchange the link state database with each neighbor controller and traditional routers in the network, the link
• state database including a cost of each shortest route between each border switch pair in
• the area of the controller;
• and
• a routing table storage device communicatively coupled to the network processor, the routing table storage device configured to store routing tables for the controller module, including shortest path information for the area of the controller and between border switches of the area of the controller.