IPv6 Configuration Guide K/KA/KB.15.15

For example, 2001:db8:0:f::/64 defines a range including any address
that has 2001:db8:0:f in the leftmost 64 bits.
[ type | [ summary [ cost 1 - 16777215 ]] | inter-area |
nssa ] [ no-advertise ]
Configures the type of route summaries to advertise or block.
[summary [ cost 1 - 16777215 ]]
Specifies internal routes in the configured range of route advertisements. If
no-advertise (above) is used in the command, then the ABR prevents
the selected internal routes from being summarized in a type-3 LSA and
advertised to the backbone. If no-advertise is not used in the command,
then the selected routes are summarized to the backbone in a type-3 LSA.
cost 1 - 16777215
User configured cost for an area summary range. If cost is specified,
then the range will advertise the specified cost instead of the calculated
cost.
inter-area
Specifies internal routes in the configured range of RAs. If no-advertise
(below) is used in the command, the ABR prevents the selected internal
routes from being summarized in an inter-area-prefix-LSA and advertised to
the backbone.
If no-advertise is not used in the command, the selected routes are
summarized to the backbone in an inter-area-prefix-LSA. (The inter-area
keyword in OSPFv3 is the equivalent of the summary keyword in OSPFv2.)
nssa
Specifies external routes (type-7-LSAs) in the configured range of RAs.
If no-advertise (below) is used in the command, the ABR prevents the
selected external routes from being summarized in an AS-external-LSA and
advertised to the backbone. (Configure this option where an ABR for an
NSSA advertises external routes that you do not want propagated to the
backbone.)
If no-advertise is not used in the command, the selected routes learned
from type-7-LSAs in the area are summarized to the backbone in an
AS-external-LSA.
The no form of the command removes the specified range from the
configuration.
no-advertise
Use this keyword only if you want to configure the ABR to prevent advertisement
to the backbone of a specified range of routes. (This has the effect of "hiding"
the specified range from the backbone area.)
If you do not use this option, the ABR advertises the specified range of routes
according to the type [ inter-area | nssa ] selection described above.
Configuring ranges on an ABR to reduce advertising to the backbone 219