Layer 3 VXLAN gateway in EVPN-VXLAN topology with a centrally-routed bridging overlay

These devices can function as a Layer 3 VXLAN gateway, or spine device, in an EVPN-VXLAN topology with a centrally-routed bridging overlay. In this role, the device uses integrated routing and bridging (IRB) interfaces to route traffic between hosts in different virtual networks (VNs) created by the Contrail virtualization software. When physical (bare-metal) servers in one VN need to communicate with other physical servers or virtual machines (VMs) in anothe VN, you can also configure an IRB interface as a default Layer 3 gateway that handles the inter-VN traffic for physical servers. In an EVPN-VXLAN topology where a provider edge (PE) device such as a Layer 2 VXLAN gateway or a Contrail vRouter is multihomed in active-active mode to two Layer 3 VXLAN gateways, you can configure redundant default gateways on the Layer 3 VXLAN gateways.