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 controller may control switches in a network that forwards network packets between end hosts. The controller may generate a directed acyclic graph based on maintained network topology information. The directed acyclic graph may include multiple network paths between any given pair of switches. For a given network packet received from an end host, the controller may generate an identifier or otherwise classify the network packet based on network attributes of the network packet. The network attributes may include packet header information retrieved from the network packet, information maintained by the controller such as which virtual switch is associated with the network packet, and/or other network attributes. The controller may use the network packet identifier to select a network forwarding path for the network packet from the directed acyclic graph.

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.