Abstract: A network of switches having ports coupled to other switches or end hosts may be controlled by a controller. The controller may identify whether any switch ports have failed. In response to identifying that a port has failed at a first switch, the controller may modify link aggregation group mappings of the other switches to handle failover. The controller may modify the link aggregation group mapping of each other switch to include a first mapping that includes ports coupled to the first switch and a second mapping that does not include any ports coupled to the first switch. The controller may configure forwarding tables at the switches to forward network packets using the first or second mappings based on network topology information maintained by the controller.

Abstract: A controller implemented on computing equipment may be used to control switches in a network. End hosts may be coupled to the switches. The controller may generate a virtual network topology of virtual switches, virtual routers, and virtual system routers that are distributed over underlying switches in the network. The controller may form virtual switches from respective groups of end hosts, virtual routers from groups of virtual switches that include virtual interfaces that are coupled to virtual switches, and a virtual system router from groups of virtual routers that includes virtual system router interfaces that are coupled to the virtual routers. The controller may control the virtual network topology by generating respective flow table entries based on identified network policies for each of the virtual routers, virtual system routers, and virtual switches. The controller may control the virtual system routers to route packets between the virtual routers.

Abstract: A packet forwarding network may include switches that forward network traffic between end hosts that are coupled to the forwarding network. An analysis network may be connected to the forwarding network. A controller may control the switches in the forwarding network to implement desired forwarding paths. The controller may configure the switches to form switch port groups. The controller may identify a port group that is connected to the analysis network. The controller may select a subset of the forwarded packets and may control selected switches to copy the subset to the identified port group. The controller may establish network tunnels between the switches and the port group. In this way, the controller may control the switches to perform efficient traffic monitoring regardless of the location on the forwarding network at which the traffic monitoring network is connected and without interfering with normal packet forwarding operations through the forwarding network.

Abstract: A controller implemented on computing equipment may control switches in a network. The controller may provide flow tables that implement network policies to the switches to control packet forwarding through the network. The controller may provide debug table entries to the switches for use in a debug table that is separate from the flow table. The debug table entries may match incoming network packets and increment corresponding counters on the switches. The controller may retrieve count information from the counters for performing debugging operations on the network. For example, the controller may identify conflicts between fields of a selected flow table entry, determine whether elephant packet flows are present between switches, determine whether desired load balancing is being performed, determine whether a network path has changed, determine whether packet loss has occurred, and/or determine whether network packets are taking undesired paths based on the retrieved count information.

Abstract: A controller implemented on computing equipment may be used to control switches in a network. End hosts and service devices may be coupled to the switches in the network. The controller may generate a virtual network topology of virtual switches and virtual routers. The controller may control the virtual routers and/or virtual switches to perform service insertion. The controller may perform service insertion by controlling the virtual routers and/or virtual switches to redirect network traffic through one or more selected service devices. The controller may determine which network traffic is to be redirected to which service devices based on a service insertion policy that identifies network traffic and services to be performed on the network traffic.

Abstract: A packet forwarding network may include switches that forward network traffic between end hosts that are coupled to the forwarding network. An analysis network may be connected to the forwarding network. A controller may control the switches in the forwarding network to implement desired forwarding paths. The controller may configure the switches to form switch port groups. The controller may identify a port group that is connected to the analysis network. The controller may select a subset of the forwarded packets and may control selected switches to copy the subset to the identified port group. The controller may establish network tunnels between the switches and the port group. In this way, the controller may control the switches to perform efficient traffic monitoring regardless of the location on the forwarding network at which the traffic monitoring network is connected and without interfering with normal packet forwarding operations through the forwarding network.

Abstract: A network of switches having ports coupled to other switches or end hosts may be controlled by a controller. The controller may identify whether any switch ports have failed. In response to identifying that a port has failed at a first switch, the controller may modify link aggregation group mappings of the other switches to handle failover. The controller may modify the link aggregation group mapping of each other switch to include a first mapping that includes ports coupled to the first switch and a second mapping that does not include any ports coupled to the first switch. The controller may configure forwarding tables at the switches to forward network packets using the first or second mappings based on network topology information maintained by the controller.

Abstract: A controller implemented on computing equipment may control switches in a network. The controller may provide flow tables that implement network policies to the switches to control packet forwarding through the network. The controller may provide debug table entries to the switches for use in a debug table that is separate from the flow table. The debug table entries may match incoming network packets and increment corresponding counters on the switches. The controller may retrieve count information from the counters for performing debugging operations on the network. For example, the controller may identify conflicts between fields of a selected flow table entry, determine whether elephant packet flows are present between switches, determine whether desired load balancing is being performed, determine whether a network path has changed, determine whether packet loss has occurred, and/or determine whether network packets are taking undesired paths based on the retrieved count information.

Abstract: A controller implemented on computing equipment may be used to control switches in a network. End hosts may be coupled to the switches. The controller may generate a virtual network topology of virtual switches, virtual routers, and virtual system routers that are distributed over underlying switches in the network. The controller may form virtual switches from respective groups of end hosts, virtual routers from groups of virtual switches that include virtual interfaces that are coupled to virtual switches, and a virtual system router from groups of virtual routers that includes virtual system router interfaces that are coupled to the virtual routers. The controller may control the virtual network topology by generating respective flow table entries based on identified network policies for each of the virtual routers, virtual system routers, and virtual switches. The controller may control the virtual system routers to route packets between the virtual routers.

Abstract: A controller implemented on computing equipment may be used to control switches in a network. End hosts and service devices may be coupled to the switches in the network. The controller may generate a virtual network topology of virtual switches and virtual routers. The controller may control the virtual routers and/or virtual switches to perform service insertion. The controller may perform service insertion by controlling the virtual routers and/or virtual switches to redirect network traffic through one or more selected service devices. The controller may determine which network traffic is to be redirected to which service devices based on a service insertion policy that identifies network traffic and services to be performed on the network traffic.