Hitachi GR2000 - Manual (Page 272)

4.9.1 Connection with IPv6 Router
Pay attention to the following when connecting this router and other equipment by
IPv6 routing.
4.9.1.1 Interface Address of Point-to-Point Type Line
This router handles the path information (direct-coupled path) of a point-to-point
type line as two host paths. Therefore, in a network consisting of only this router,
the interface addresses below can be allocated to the point-to-point type line. Do not
use the point-to-point type line between this router and other equipment.
An IPv6 address with the same prefix can be allocated to multiple point-to-point
type lines.
(For more details, see "Application Guide".)
An IPv6 address with a different prefix can be allocated to both ends of a
point-to-point type line.
(For more details, see "Application Guide".)
However, the intensive setting of path information is complicated when the addresses