The disclosure describes examples where a first data center includes a first gateway router, a first set of computing devices, and a second set of computing devices. The first set of computing devices is configured to execute a software defined networking (SDN) controller cluster to facilitate operation of one or more virtual networks within the first data center. The second set of computing devices is configured to execute one or more control nodes to exchange route information, between the first gateway router and a second gateway router of a second data center different than the first data center, for a virtual network between computing devices within the second data center, and to communicate control information for the second data center to the second set of computing devices, wherein the one or more control nodes form a subcluster of the SDN controller cluster.

In general, this disclosure describes a programmable network platform for dynamically programming a cloud exchange to provide a layer three (L3) routing instance as a service to customers of the cloud exchange. In one example, a cloud exchange comprises an L3 network located within a data center and configured with an L3 routing instance for an enterprise; and for the L3 routing instance, respective first and second attachment circuits for first and second cloud service provider networks co-located within the data center, wherein the L3 routing instance stores a route to a subnet of the second cloud service provider network to cause the L3 routing instance to forward packets, received from the first cloud service provider network via the first attachment circuit, to the second cloud service provider network via the second attachment circuit.

In general, this disclosure describes a programmable network platform for dynamically programming a cloud exchange to provide a layer three (L3) routing instance as a service to customers of the cloud exchange. In one example, a cloud exchange comprises an L3 network located within a data center and configured with an L3 routing instance for an enterprise; and for the L3 routing instance, respective first and second attachment circuits for first and second cloud service provider networks co-located within the data center, wherein the L3 routing instance stores a route to a subnet of the second cloud service provider network to cause the L3 routing instance to forward packets, received from the first cloud service provider network via the first attachment circuit, to the second cloud service provider network via the second attachment circuit.

A method for generating an application-aware virtual topology (AAVT) routing table for a network device among network devices connected via a wide area network is provided. The method is executed by a network controller connected to the network and includes: receiving, from the network devices, path information of the network devices; generating, using the path information, an underlay graph specifying a path topology of the network device; generating, based on the path topology specified in the underlay graph, the AAVT routing table for the network device where the AAVT routing table includes a set of paths; and transmitting, in response to generating the AAVT routing table, the AAVT routing table to the network device to cause the network device to program the set of paths.

A method for generating an application-aware virtual topology (AAVT) routing table for a network device among network devices connected via a wide area network is provided. The method is executed by a network controller connected to the network and includes: receiving, from the network devices, path information of the network devices; generating, using the path information, an underlay graph specifying a path topology of the network device; generating, based on the path topology specified in the underlay graph, the AAVT routing table for the network device where the AAVT routing table includes a set of paths; and transmitting, in response to generating the AAVT routing table, the AAVT routing table to the network device to cause the network device to program the set of paths.

Example methods and systems for packet handling in a software-defined networking (SDN) environment are disclosed. One example method may comprise detecting an egress application-layer message from a first logical endpoint supported by a first host; and identifying a second logical endpoint supported by the second host for which the egress application-layer message is destined. The method may also comprise generating an egress packet that includes the egress application-layer message and metadata associated with the second logical endpoint, but omits one or more headers that are addressed from the first logical endpoint to the second logical endpoint. The method may further comprise sending the egress packet to the second host to cause the second host to identify the second logical endpoint based on the metadata, and to send the egress application-layer message to the second logical endpoint.

An embodiment is directed to switchover operations with a virtualized network device in a cloud or remote infrastructure. The virtualized hardware switchover operations may be used to selectively and temporarily provide virtualized control-plane operations to the data-plane of a non-redundant network device undergoing an upgrade or a reboot of its control plane. A non-redundant network device may operate hitless, or near hitless, operation even when its control plane is unavailable.

A network system that uses a cluster of edge nodes to send and receive multicast traffic is provided. The network system is a network virtualization environment that includes one or more distributed routers, each distributed router implemented by virtualization software running on one or more host machines. The network system also includes a cluster of edge nodes for sending data from the one or more distributed routers to one or more uplink/upstream physical routers outside of a datacenter and for receiving data from the physical routers to the distributed routers. One of the edge nodes is a designated edge node that queries for membership information for one or more multicast groups to be received by at least two edge nodes of the cluster of edge nodes. The cluster of edge nodes forwards multicast traffic to and from the distributed routers according to the received membership information.

A network system that uses a cluster of edge nodes to send and receive multicast traffic is provided. The network system is a network virtualization environment that includes one or more distributed routers, each distributed router implemented by virtualization software running on one or more host machines. The network system also includes a cluster of edge nodes for sending data from the one or more distributed routers to one or more uplink/upstream physical routers outside of a datacenter and for receiving data from the physical routers to the distributed routers. One of the edge nodes is a designated edge node that queries for membership information for one or more multicast groups to be received by at least two edge nodes of the cluster of edge nodes. The cluster of edge nodes forwards multicast traffic to and from the distributed routers according to the received membership information.

For logical multicasting in overlay networks, at a data processing system, an original unicast packet is received from a first component in a first computing node in an overlay network. To cause multicasting in the overlay network the received original unicast packet was unicast by the first computing node only to the data processing system, and a multicast data structure for the overlay network is maintained only by the data processing system, the multicast data structure containing information of each receiver that is configured to receive unicast packets during logical multicasting in the overlay network. From a set of subscriber receivers in the multicast data structure, a subset of the subscriber receivers is selected. A copy of the original unicast packet is unicast to each subscriber receiver in the subset.