A label-IPv6 is automatically added as a BGP tunnel entry to the tunnel table if all of the following conditions are met.
The label-IPv6 route is the best BGP path for a /128 IPv6 prefix is a label-IPv6 route (AFI 2, SAFI 4).
The label-IPv6 route has the numerically lowest preference value among all routes (regardless of protocol) for the /128 IPv6 prefix.
The disable-route-table-install command does not apply to the route.
The disable-explicit-null command is configured.
If multipath and ECMP are configured so that they apply to label IPv6 routes, a BGP tunnel can be installed in the tunnel table with multiple ECMP next-hops, each one corresponding to a path through a different BGP next-hop. However, when disable-explicit-null is configured, the label-IPv6 routes used for ECMP toward an IPv6 destination cannot be a mix of routes with regular label values and routes with special (IPv6 explicit null) label values.