Abstract: Systems for and methods of modelling, analyzing and managing data networks are provided. In an embodiment, a plurality of network device interfaces are configured to collect state information for a plurality of network devices. A computer-implemented model of the network comprises a data structure, which may be graph-based. The data structure comprises a plurality of snapshots of the network, each snapshot representing the network at a particular point in time, and the data structure comprises a representation of possible data flow and data packet processing within the network. The data structure contains normalized representations of the network devices corresponding to the location. The normalized representation for each device contains a set of packet processing rules. A user-interface is configured to receive queries from a user that request verification of network policies and predictions of network behavior.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a network controller that manages a plurality of managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method inserts the packet into a managed forwarding element associated with the particular source such that the managed forwarding element processes the packet as though the packet was received from the particular source. The method receives, from a set of managed forwarding elements, a set of messages regarding logical processing operations and physical forwarding operations that each managed forwarding element in the set of managed forwarding elements performs on the packet.

Abstract: Some embodiments provide a method for a first network controller that manages a set of logical forwarding elements implemented in several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method sends the packet to a second network controller that manages a managed forwarding element associated with the particular source. The method receives a first set of messages regarding operations performed on the packet from a set of network controllers that receives a second set of messages regarding operations performed on the packet from a set of managed forwarding elements that process the packet.

Abstract: Some embodiments provide a method for a network controller that manages a plurality of managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method inserts the packet into a managed forwarding element associated with the particular source such that the managed forwarding element processes the packet as though the packet was received from the particular source. The method receives, from a set of managed forwarding elements, a set of messages regarding logical processing operations and physical forwarding operations that each managed forwarding element in the set of managed forwarding elements performs on the packet.