+symmetric model
+^^^^^^^^^^^^^^^
+
+With this model, you don't need to have all vxlan on all nodes.
+This model will also be needed to route traffic to an external router.
+
+The symmetric model routes and bridges on both the ingress and the egress leafs.
+This results in bi-directional traffic being able to travel on the same VNI, hence the symmetric name.
+However, a new specialty transit VNI is used for all routed VXLAN traffic, called the L3VNI.
+All traffic that needs to be routed will be routed onto the L3VNI, tunneled across the layer 3 Infrastructure,
+routed off the L3VNI to the appropriate VLAN and ultimately bridged to the destination.
+
+A vrf is needed for the L3VNI, so all vmbr bridge need to be in the vrf if they want to be able to reach each others.
+
+image::images/vxlan-l3-symmetric.svg["vxlan l3 symmetric",align="center"]
+
+sysctl.conf tuning
+
+----
+#enable routing
+net.ipv4.ip_forward=1
+net.ipv6.conf.all.forwarding=1
+#disable reverse path filtering
+net.ipv4.conf.default.rp_filter=0
+net.ipv4.conf.all.rp_filter=0
+#allow frr to work with vrf (kernel >4.14 bug)
+net.ipv4.tcp_l3mdev_accept=1
+----
+
+* node1