1- create the virtual router
2- in traffic: pop S-VLAN, on the way out push S-VLAN
set xe-0/0/0 flexible-vlan-tagging
set xe-0/0/0 encapsulation extended-vlan-bridge
set xe-0/0/0 unit 0 vlan-id 100
set xe-0/0/0 unit 0 input-vlan-map pop # pop S-VLAN incoming traffic ( only C-VLAN will be kept )
set xe-0/0/0 unit 0 output-vlan-map push # push/restore S-VLAN outgoing traffic ( only C-VLAN was kept )
set vlans vtest interface xe-0/0/0.0
set vlans vtest vxlan vni 100
set vlans vtest vxlan encapsulate-inner-vlan # keep the C-VLAN
set vlans vtest vxlan ingress-node-replication # keep the C-VLAN