This VXLAN BGP EVPN example shows how to transmit VXLAN traffic to an external network. Traffic from a tenant host that is destined to the Internet is transmitted to a border leaf gateway over L3 VTEPs and an IP underlay fabric.
NOTE: After VXLAN decapsulation, routing between virtual networks and tenant VLANs is supported only on the S4200-ON series and S5200-ON series due to NPU capability. On other Dell EMC switches that support VXLAN routing, such as S4048T-ON, S6010-ON, and the S4100-ON series, routing after decapsulation is performed only between virtual networks. You can connect an egress virtual network to a VLAN in an external router, which connects to the external network.
In the following example, VLT domain 1 is a VLT VTEP. VLT domain 2 is the border leaf VLT VTEP pair. All virtual networks in the data center network are configured in all VTEPs with virtual-network IP and anycast IP gateway addresses.
Configure a dedicated virtual network for sending VXLAN traffic to an external network on all VTEPs. Configure the anycast L3 gateway for the dedicated virtual network only on the border leaf VTEP pair in VLT domain 2. For asymmetric IRB, configure a static default route on all VTEPs, except the border leaf VTEPs. This allows traffic destined to an external network to be transmitted to the anycast L3 address of the dedicated virtual network on the border leaf VTEP. A different static route is configured on the border leaf VTEP. Using this second static route, traffic to an external network is transmitted on an egress VLAN to a WAN router or an Internet address.
When VLT domain 1 receives traffic destined to an external network, the traffic is routed to the dedicated virtual network in the ingress VTEP and sent to the border leaf VTEP. On the border leaf VTEP, the traffic is routed to the VLAN to which an external WAN router is connected or directly connected to the Internet. Similarly, any traffic destined to a VXLAN virtual network that is received on the border leaf VTEP is routed to the destination virtual network.
NOTE: This border leaf gateway example for VXLAN BGP EVPN uses the same configuration steps as in
Example: VXLAN BGP EVPN — Multiple AS topology. Configure each spine and leaf switch as in the Multiple AS topology example and add the following additional configuration steps on each VTEP.