Abstract: Some embodiments provide a program that monitors several network controllers in a network. Each network controller manages a logical data path set that is implemented across several managed switching elements. The program detects that a first network controller in the several network controllers has failed. The program selects a second network controller in the several network controllers to manage the logical data path set managed by the first network controller.

Abstract: A control system including several controllers for managing several switching elements. A first controller registers a second controller for receiving a notification when a data tuple changes in a network information base (NIB) storage of the first controller that stores data for managing a set of switching elements. The first controller changes the data tuple in the NIB. The first controller sends the notification to the second controller of the change to the data tuple in the NIB. The first and second controllers operate on two different computing devices. Each controller receives logical control plane data for specifying logical datapath sets and converts the logical control plane data to physical control plane data for enabling the switching elements to implement the logical datapath sets.

Abstract: A network control system for managing several switching elements. The network control system includes first and second controllers for generating data for managing first and second sets of switching elements. The first controller is further for serving as a master controller of the first set of switching elements. The second controller is further for serving as a master controller of the second set of switching elements. The master controller for a particular set of switching elements is the only controller that is allowed to propagate data to the particular set of switching elements data for managing the particular set of switching elements.

Abstract: Some embodiments provide a program for managing several switching elements. The program receives, at a network information base (NIB) data structure that stores data for managing the several switching elements, a request to modify data stored in at least one particular switching element. The program modifies at least a first set of data tuples stored in the NIB for managing the particular switching element. The program sends a request to the particular switching element to modify at least a second set of data tuples for managing the particular switching element's operation.

Abstract: A network control system that includes several controllers for managing several switching elements and a distributed hash table (DHT) formed across the controllers for storing data regarding the switching elements that is accessible by the controllers. Each hash table serves as a DHT instance. In some embodiments, the DHT instances of all controller instances collectively store one set of records that is indexed based on hashed indices for quick access. These records are distributed across the different controller instances to minimize the size of the records within each instance and to allow for the size of the DHT to be increased by adding other DHT instances. According to this scheme, each DHT record is not stored in each controller instance. In fact, in some embodiments, each DHT record is stored in at most one controller instance.

Abstract: Some embodiments provide a program for managing several switching elements. The program receives, at a network information base (NIB) data structure that stores data for managing the several switching elements, a request to notify a first application that uses the NIB when a set of data stored in the NIB is changed. The program changes, in response to an instruction from a second application, the set of data in the NIB. The program sends a notification to the first application of the change to the set of data in the NIB.

Abstract: Some embodiments provide a system for managing several switching elements. The system includes a network information base (NIB) data structure for serving as a primary storage structure for storing data for managing the several switching elements. The system includes a secondary storage structure for storing a copy of a set of data stored in the primary storage structure for managing the several the switching elements.

Abstract: Systems and methods for managing a network are described. A view of current state of the network is maintained where the current state of the network characterizes network topology and network constituents, including network entities and network elements residing in or on the network. Events are announced that correspond to changes in the state of the network and one or more network elements can be configured accordingly. Methods for managing network traffic are described that ensure forwarding and other actions taken by network elements implement globally declared network policy and refer to high-level names, independently of network topology and the location of network constituents. Methods for discovering network constituents are described, whereby are automatically configured. Routing may be performed using ACL and packets can be intercepted to permit host to continue in sleep mode. The methods are applicable to virtual environments.