A VRF route learned on PE1 is not installed into the VRF on PE2 even though PE2 received a VPNv4 update. Which BGP attribute determines whether PE2 imports that route into the local VRF?

The Route Target (RT) extended community is crucial for VPNv4 route import. When PE1 advertises a VPNv4 route, it attaches an export RT. PE2 receives this route and compares the export RT with its locally configured import RTs for a specific VRF. If there's a match, PE2 imports the route into that VRF. If no match occurs, the route is not imported, even if received via MP-BGP. The Route Distinguisher (RD) makes VPNv4 prefixes unique within BGP but doesn't control import. BGP MED influences path selection after a route is imported, not the import process itself. The MP-BGP next-hop indicates where to forward traffic for the route but doesn't dictate whether the route is imported into a VRF.