It is common to configure route-reflector outside the PE, either on the dedicated router or on the P router. These routers may not have LSP configured (in rsvp-based network) or may not be running MPLS at all.

regress@RR1_RE> show bgp summary  
22.22.22.22           64513       5519       5518       0       3 1d 17:55:43 Establ
  bgp.l3vpn.0: 0/3/3/0.    

regress@RR1_RE> show route receive-protocol bgp 22.22.22.22 table bgp.l3vpn.0 hidden 

bgp.l3vpn.0: 6 destinations, 6 routes (3 active, 0 holddown, 3 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
  64513:1:10.49.96.0/19                    
                          8.8.8.8                                 64513 I
  64513:1:20.20.20.20/32                    
                          8.8.8.8                                 64513 I
  64513:1:172.16.20.4/30                    
                          8.8.8.8                                 64513 I

These routes are hidden because Route Reflector is not running MPLS/ RSVP/ LDP on it. In order to resolve these routes, next-hop should be resolved in inet.3 table, and MPLS does not have one. 

The statement below enables an override of the default routing tables that Junos OS uses for route resolution. For example, lets say the resolution routing table is inet.3 , but you want to allow fallback resolution through inet.0 . Similarly, bgp.l3vpn.0 table, and the configured resolution routing table is inet.0. We can specify single or more routing tables to use route resolution.

regress@RR1_RE> show configuration routing-options 
resolution {
    rib inet.3 {
        resolution-ribs inet.0;
    }
    rib bgp.l3vpn.0 {
        resolution-ribs inet.0;
    }