An ABR maintains an LSDB for each area. There are many LSDBs on an ABR.

The metric of an ASE LSA can be specified when an external route is imported. The default value is 1.

The external routing information carries a Tag label for transmitting additional information of the route. It is commonly used in a routing policy. The default value of the Tag label is 0.

The Link State ID in an ASBR-Summary-LSA is the Router ID of the ASBR.