MPLS BGP VPN’s not supported across un-numbered interfaces.
When using an un-numbered interface between PE and P routers instead of IP numbered interfaces, the ERX no longer displays VPN routes and shows the next hop address and unreachable even though ICMP Pings to the next hop address are successful.
Platform: Juniper E-Series
show ip bgp vpn vrf test 192.168.2.0
BGP route information for prefix 192.168.2.0/24
Received route learned from internal peer 220.127.116.11
Route not placed in IP forwarding table
Do not advertise to any peers
Address Family Identifier (AFI) is ip-v4
Subsequent Address Family Identifier (SAFI) is unicast
Route Distinguisher (RD) is 19262:23101
Original Route Distinguisher (RD) is 19262:23010
MPLS in-label is none
MPLS out-label is 20
Next hop IP address is 18.104.22.168 (not reachable)
Multi-exit discriminator is 0
Local preference is 100
Weight is 0
Origin is Incomplete
AS path is empty
Extended communities RT:19262:23010
MPLS BGP VPN’s are not supported on un-numbered interfaces. Assigning an IP address to the interface will allow MPLS Tunnels to be built, and display VPN routes correctly.