Abstract: Some embodiments provide a method for configuring a logical middlebox in a hosting system that includes a set of nodes. The logical middlebox is part of a logical network that includes a set of logical forwarding elements that connect a set of end machines. The method receives a set of configuration data for the logical middlebox. The method uses a stored set of tables describing physical locations of the end machines to identify a set of nodes at which to implement the logical middlebox. The method provides the logical middlebox configuration for distribution to the identified nodes.

Abstract: Some embodiments provide a novel method for forwarding a packet at a managed switching element in a first domain. The method receives a packet from a local machine. The method encapsulates the packet with a first context identifier that identifies a first logical port of a first logical switching element that couples to machines in both the first domain and a second domain. The first logical port maps to a destination address of the packet. Based on a mapping of the first logical port to a second logical port of a second logical switching element that couples to machines in only the first domain, the method encapsulates the packet with a second context identifier that identifies the second logical port. The method transmits the twice-encapsulated packet out of a port of the managed switching element based on the second context identifier.

Abstract: Some embodiments provide a method for an application operating on a host machine. The method receives a configuration of a Dynamic Host Configuration Protocol (DHCP) service for implementation within a virtualized container on the host machine. The configuration includes several database table entries. The method converts the several database table entries into a configuration file for use by a process that operates in the virtualized container. the method initializes the process in the virtualized container. The process in the virtualized container reads the configuration file in order to perform DHCP services for machines connected to at least one logical forwarding element of a logical network.

Abstract: Some embodiments provide a method for a network controller that manages several logical networks. The method receives a specification of a logical network that includes at least one logical forwarding element attached to a logical service (e.g., DHCP). The method selects at least one host machine to host the specified logical service from several host machines designated for hosting logical services. The method generates logical service configuration information for distribution to the selected host machine. In some embodiments, the method selects a master host machine and a backup host machine for hosting logical service. In some embodiments, a particular one of the designated host machines hosts at least two DHCP services for two different logical networks as separate processes operating on the particular host machine.

Abstract: A novel method for logically routing a packet between a source machine that is in a first logical domain and a destination machine that is in a second logical domain is described. The method configures a managed switching element as a second-level managed switching element. The method configures a router in a host that includes the second-level managed switching element. The method communicatively couples the second-level managed switching element with the router. The method causes the router to route a packet when the router receives a packet from the first logical domain that is addressed to the second logical domain.

Abstract: Some embodiments provide a method for using headerspace analysis. The method receives several flow entries for distribution to a forwarding element in a network. Each flow entry includes a set of conditions to be matched by a packet header and a set of actions to perform on a packet that matches the set of conditions. The method models each of the flow entries as a function that operates on a representation of a packet header. The method determines a set of packet headers of packets to be received by the forwarding element. The method determines a set of the flow entries that are not matched by a packet header of any packet to be received by the forwarding element by applying the functions to representations of the identified set of packet headers.

Abstract: Some embodiments provide a method that uses headerspace analysis. The method receives several flow entries for distribution to a set of forwarding elements that implement a logical network. The method models each of the flow entries as a function that operates on a representation of a packet header. The method uses the modeled functions to identify a set of paths from a packet source to a packet destination. For each particular path of the identified paths, the method uses inverses of the modeled functions to determine a set of packet headers. Packets sent from the packet source with any packet header in the set of packet headers follow the particular path through the flow entries.

Abstract: Some embodiments provide a method of processing an incoming packet for a managed forwarding element that executes in a host to forward packets in a network. The method performs a lookup into a forwarding table to identify a flow entry matched by the incoming packet. The flow entry specifies a high-level action to perform on the incoming packet. The method provides packet data to a module executing separately from the managed forwarding element in the host. The module performs a set of processes in order to identify a set of low-level actions for the managed forwarding element to perform on the incoming packet without additional lookups into the forwarding table. The method receives data from the separate module specifying the set of low-level actions. The method performs the set of low-level actions on the incoming packet in order to further process the packet.

Abstract: A controller of a network control system for configuring several middlebox instances is described. The middlebox instances implement a middlebox in a distributed manner in several hosts. The controller assigns a first set of identifiers to a first middlebox instance that associates an identifier in the first set with a first packet. The controller assigns a second set of identifiers to a second middlebox instance that associates an identifier in the second set with a second packet.

Abstract: Core dump is performed over a network without relying on network device drivers. Instead of network device drivers, firmware of network devices that is typically used during boot is preserved in memory post-boot, and one or more application program interfaces of the firmware are invoked to perform the network core dump. For ease of implementation, a network bootstrap program that has standard application program interfaces for calling into the firmware of network devices may be invoked when performing core dump over the network.

Abstract: Some embodiments provide a novel method for forwarding a packet at a managed switching element in a first domain. The method receives a packet from a local machine. The method encapsulates the packet with a first context identifier that identifies a first logical port of a first logical switching element that couples to machines in both the first domain and a second domain. The first logical port maps to a destination address of the packet. Based on a mapping of the first logical port to a second logical port of a second logical switching element that couples to machines in only the first domain, the method encapsulates the packet with a second context identifier that identifies the second logical port. The method transmits the twice-encapsulated packet out of a port of the managed switching element based on the second context identifier.

Abstract: A network control system that includes a first set of network controllers for (i) receiving a logical control plane definition of a logical switching element that couples to both a first set of network hosts in a first domain and a second set of network hosts in a second domain, (ii) translating the logical control plane definition of the logical switching element into a first set of flow entries in a first logical forwarding plane, and (iii) translating the first set of flow entries into a second set of flow entries in a second logical forwarding plane. The network control system includes a second set of network controllers in the first domain for (i) receiving a portion of the second set of flow entries and (ii) translating the portion of the second set of flow entries into a third set of flow entries in a physical control plane.

Abstract: A novel method for configuring first and second managed forwarding elements to perform logical L2 switching and L3 routing is described. The method generates a first set of flow entries for configuring the first managed forwarding element to perform logical L2 ingress processing and L3 routing processing. The method generates a second set of flow entries for configuring the second managed forwarding element to performing logical L2 egress processing.

Abstract: Some embodiments provide a novel network control system for managing a set of switching elements in a network. The network control system includes a first set of network controllers for managing a first set of switching elements that enable communication between a first set of machines. The network control system includes a second set of network controllers for managing a second set of switching elements that enable communication between a second set of machines. The second set of switching elements is separate from the first set of switching elements and the second set of machines is separate from the first set of machines. The network control system includes a third set of network controllers for managing the first and second sets of network controllers in order to enable communication between machines in the first set of machines and machines in the second set of machines.

Abstract: A network control system for interconnecting several separate networks. The system includes i) several interconnection switching elements, each of which is for connecting one of the separate networks to a common interconnecting network, ii) a first set of network controllers for managing a first set of the interconnection switching elements at a first set of separate networks in order for machines at different networks within the first set to communicate with each other, iii) a second set of network controllers for managing a second set of interconnection switching elements at a second set of separate networks in order for machines at different networks within the second set to communicate with each other, and iv) a third set of network controllers for managing the first and second sets of network controllers in order for machines at networks in the first set to communicate with machines at networks in the second set.

Abstract: Core dump is performed over a network without relying on network device drivers. Instead of network device drivers, firmware of network devices that is typically used during boot is preserved in memory post-boot, and one or more application program interfaces of the firmware are invoked to perform the network core dump. For ease of implementation, a network bootstrap program that has standard application program interfaces for calling into the firmware of network devices may be invoked when performing core dump over the network.

Abstract: A virtual device emulated in software and included in a virtual machine is provided in a virtualized computer system. The virtual device includes an emulation mode and a pass through mode. The emulation mode is used for a first plurality of device operations. The pass through mode is used for a second plurality of device operations. The virtual device is configured to communicate with a physical device and each of the second plurality of device operations are configured to be handled by the physical device. The virtual device also includes a switching logic to switch between the emulation mode and the pass through mode based on a device operation to be performed by the virtual machine of the virtual device.

Abstract: Techniques for managing feedback control systems are provided. By way of example, a method of controlling performance of a managed system by a controller includes the following steps/operations. The controller issues a control value to the managed system to affect a performance of the managed system. The controller maintains a measurement time period having a variable start time within which the performance of the managed system is measured, such that the control value is given time to take effect on the managed system and a performance metric fed back to the controller from the managed system reflects the effect of the control value on the managed system.

Abstract: The present invention is directed to a method and system of memory management that features dual buffer rings, each of which includes descriptors identifying addresses of a memory space, referred to as buffers, in which portions of data packets are stored. Typically, the header segment of each data packet is stored at a first set of a plurality of buffers, and the portion of the payload segment that does not fit among the buffers of the first set is stored in the buffers of a second set. In this manner, the size of the individual buffers associated with the first buffer rings may be kept to the smallest size of useable storage space, and the buffers corresponding to the second buffer ring may be arbitrary in size.

Abstract: A virtual device emulated in software and included in a virtual machine is provided in a virtualized computer system. The virtual device includes an emulation mode and a pass through mode. The emulation mode is used for a first plurality of device operations. The pass through mode is used for a second plurality of device operations. The virtual device is configured to communicate with a physical device and each of the second plurality of device operations are configured to be handled by the physical device. The virtual device also includes a switching logic to switch between the emulation mode and the pass through mode based on a device operation to be performed by the virtual machine of the virtual device.