The Area Aggregate Table acts as an adjunct
to the Area Table. It describes those address aggregates
that are configured to be propagated from an area.
Its purpose is to reduce the amount of information
that is known beyond an Area's borders.
It contains a set of IP address ranges
specified by an IP address/IP network mask pair.
For example, a class B address range of X.X.X.X
with a network mask of 255.255.0.0 includes all IP
addresses from X.X.0.0 to X.X.255.255.
Note that if ranges are configured such that one range
subsumes another range (e.g., 10.0.0.0 mask 255.0.0.0
and 10.1.0.0 mask 255.255.0.0),
the most specific match is the preferred one.