Abstract: Some embodiments provide a method for an orchestration program instance assigned a particular network device in a network. Each network device of multiple network devices is assigned to a different orchestration program instance in a cluster. The method receives a notification message that a configuration for the particular network device has been modified. In response to the notification message, the method identifies a set of network correctness requirements to be evaluated for the network. The method sends a separate notification message for each identified network correctness requirement specifying that the particular network device configuration has been modified so that a set of evaluation program instances can re-evaluate any network correctness requirements dependent on the particular network device.

Abstract: Some embodiments provide a method for evaluating a network correctness requirement at an evaluation program instance assigned to evaluate a particular network correctness requirement. The method identifies data message properties associated with the particular network correctness requirement. The method evaluates the particular network correctness requirement by (i) determining a path through a set of network devices for a data message having the identified data message properties and (ii) from a data storage that stores data message processing rules for a plurality of network devices including the set of network devices and additional network devices, retrieving and storing in memory data specifying data message processing rules for the set of network devices to use in evaluating the particular network correctness requirement.

Abstract: Some embodiments provide a method for evaluating a network. The method identifies multiple network correctness requirements configured for the network. The method instantiates a separate respective evaluation program instance for each respective identified network correctness requirement to evaluate the respective network correctness requirement. At least two evaluation program instances are instantiated on different machines. Each respective evaluation program instance stores in a respective memory a respective set of network device data to evaluate the respective network correctness requirement. Each set of network device data requires less memory than storing network device data for the entire network.