MPLS Route Target
When implementing MPLS VPNs, we use a Route Target or RT to allow PE routers to control the distribution of VPN routes to the appropriate VRFs.
Now an RT is actually a BGP extended community attribute that is used to control the distribution of VPN routing information between PE routers. The RT acts as a tag for VPN routes, and it is attached to the BGP update messages. There are two types of Route Targets: import RT and export RT.
- Import RT: A PE router imports VPN routes with an import RT that matches the import RT specified in its VRF table. In this way, the import RT controls which routes are imported into a specific VRF.
- Export RT: A PE router exports VPN routes by attaching an export RT to them. The export RT controls which routes are shared with other PE routers.
An RT should not be confused with a Route Distinguisher.
Links:
https://forum.networklessons.com/t/mpls-layer-3-vpn-explained/1287/213?u=lagapides