Hi there!
A VPN target, also called the route target (RT), is a BGP extension community attribute. BGP/MPLS IP VPN uses VPN targets to control VPN routes advertisement.
A VPN instance is associated with one or more VPN target attributes. VPN target attributes are classified into the following types:
Export target: After a PE device learns IPv4 routes from directly connected sites, it converts the routes to VPN-IPv4 routes and sets the export target attribute for those routes. The export target attribute is advertised with the routes as a BGP extended community attribute.
Import target: After a PE device receives VPN-IPv4 routes from other PE devices, it checks the export target attribute of the routes. If the export target is the same as the import target of a VPN instance on the local PE device, the local PE device adds the route to the VPN routing table.
BGP/MPLS IP VPN uses VPN targets to control advertisement and receiving of VPN routes between sites. VPN export targets are independent of import targets. An export target and an import target can be configured with multiple values to implement flexible VPN access control and VPN networking.For example, if the import target of a VPN instance contains 100:1, 200:1, and 300:1, any route with the export target of 100:1, 200:1, or 300:1 is added to the routing table of the VPN instance.
Link:
https://forum.huawei.com/enterpr ... s/thread/533693-861.