When the switch learns about a local VNI and there is no configuration available in the system regarding this VNI then the import and export route targets (RTs) and route distinguisher (RD) for this VNI will be automatically calculated. The RTs are automatically derived as AS:VNI, whereas RD is derived as Router-ID:VNI-Index. For Type-2 and Type-3 routes coming from the layer 2 VNI, the RD is calculated as VXLAN-local0-tunnelip:VNI instead of Router-ID:VNI. Since EVPN routes may have the same MAC and/or the IP address; RDs are used to remove ambiguity in such cases. RTs are used to identify the VPN membership of routes.
If you do not want that route distinguisher (RD) to be automatically derived, used the command below.
set protocol bgp [l2vpn] evpn vni <1-16777215> rd <rd>
If you want route target (RT) to be configured manually instead of being auto-configured, run the command below. The value of parameter route-target can have three values, export, import or both. If you choose both then the RT is used as both import and export route target.
set protocol bgp [l2vpn] evpn vni <1-16777215> route-target {both|export|import} <route-target>