A multi-level lookup table includes a plurality of search levels with each
search level including a plurality of subtrees, each subtree representing
a plurality of nodes. A search of the multi-level lookup table for an
entry corresponding to a search key results in a value stored in an entry
associated with the node in a subtree. A default value is associated with
the root of the subtree. Multiple entries for the subtree can store the
default value. To minimize route update time, the default value
associated with the subtree is stored in a single location. Instead of
storing the default value in multiple entries, each entry stores a use
default indicator to indicate that the default value stored in the single
location is to be used. To further reduce the number of locations to
modify to update the default route, the single location can store an
inherit indicator to indicate that the default value for the subtree is
inherited from another subtree.