IPv6ユニキャストアドレス割り当て体系（ドメイン内のIPv6アドレスの管理）

   If individual hosts take their IPv6 addresses from a myriad of
   unrelated IPv6 address spaces, there will be effectively no data
   abstraction beyond what is built into existing intra-domain routing
   protocols.  For example, assume that within a routing domain uses
   three independent prefixes assigned from three different IPv6 address
   spaces associated with three different attached providers.

   This has a negative effect on inter-domain routing, particularly on
   those other domains which need to maintain routes to this domain.
   There is no common prefix that can be used to represent these IPv6
   addresses and therefore no summarization can take place at the
   routing domain boundary. When addresses are advertised by this
   routing domain to other routing domains, an enumerated list of the
   three individual prefixes must be used.

   The number of IPv6 prefixes that leaf routing domains would advertise
   is on the order of the number of prefixes assigned to the domain; the
   number of prefixes a provider's routing domain would advertise is
   approximately the number of prefixes attached to the client leaf
   routing domains; and for a backbone this would be summed across all
   attached providers.  This situation is just barely acceptable in the
   current Internet, and is intractable for the IPv6 Internet.  A
   greater degree of hierarchical information reduction is necessary to
   allow continued growth in the Internet.