PE1 router advertises intra area routes int MP-BGP. other PE2 redistributes the MP-BGP routes into OSPF as LSA type 3 (Summary address) as MPLS backbone acts as an OSPF superbackbone.
PE2 sets the Down bit on those routes to avoid routing loops in scenarios which a site is dual homed to the service provider network.
If a router receives a Type 3 LSA with its Down bit set on an interface that belongs to a VRF, it drops the LSA. In cases which the site is not dual home this loop prevention mechanism is undesirable.
To disable this behaviour the following command can be used under router ospf, which no longer perform PE specific checks:
R1(config-router)# capability vrf-lite
If the router doesn't support that command, different OSPF domain-ids should be set on the PE routers, which in turn changes the route types to External(LSA Type 5) instead of Summary (LSA Type3).
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