router ospf3 area

Syntax

router ospf3 area [ospf3-area-id|backbone] range ipv6-addr/prefix [type | summary [ cost 1 - 16777215 ]|inter-area|nssa][no-advertisement]

router ospf3 area [ospf3-area-id|backbone] range ipv6-addr/prefix [type | summary [ cost 1 - 16777215 ]|inter-area|nssa]

Description

Use this command on a routing switch intended to operate as an ABR for the specified area to do either of the following:

Simultaneously create the area and corresponding range setting for routes to summarize or block.
For an existing area, specify a range setting for routes to summarize or block (prevent).

Options

ospf3-area-id

Same area ID as in area [ospf3–area-id|backbone][ normal ], except you cannot use a backbone area number (0 or 0.0.0.0) for a stub area or NSSA.

range ipv6-addr/prefix

Defines the range of RAs to either summarize for injection into the backbone area or to prevent from being injected into the backbone area.

The ipv6-addr value specifies the IPv6 address portion of the range, and prefix specifies the leftmost significant bits in the address.

The ABR for the specified area compares the IPv6 address of each outbound RA with the address and significant bits in the mask to determine which routes to select for either summarizing or blocking.

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.

nssa

Specifies external routes (type-7-LSAs) in the configured range of RAs.

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.

Assigning a Cost

The cost parameter provides a way to define a fixed, user-assigned cost of an LSA type 3 summarized prefix.

Switch(vlan-100)#ipv6 ospf3 cost 20

CLI to verify the set value:

Switch(vlan-1)#show ipv6 ospf3 interface vlan 100

OSPFv3 configuration and statistics for VLAN 100

Interface    Status    Area ID    State    Cost    Pri    Passive
------------------------------------------------------------------
vlan-100     Enabled   0.0.0.0    DROTHER  20      1      No

Switch(vlan-1)#

The no form removes the specified range from the configuration.

ABR allowing or blocking advertisement of a range of internal routes available in an area

Example of defining a range of internal routes to advertise to the backbone

The following command defines a range of internal routes in area 30 to summarize for injection into the backbone area. (In this example, area 30 can be a normal or stub area, or an NSSA.)

Switch(ospf3)# area 30 range 2001:db8:1a/48 type inter-area

For the same range of routes, you can use either of the following commands to block injection of a range of inter-area routes (inter-area-prefix-LSAs) from area 30 into the backbone.

Switch(ospf3)# area 30 range 2001:db8:1a/48 type inter-area no-advertise

Examples of allowing or blocking a range of external routes available through an ASBR in an NSSA follow.

This example applies only to external routes that can be advertised from an NSSA to the backbone.

Switch(ospf3)# area 7 range 2001:db8:5f:1::/64 type nssa

Switch(ospf3)# area 7 range 2001:db8:7a:15::/64 type nssa no-advertise

Defines the range of external routes in the Area 7 NSSA to block from advertising to the backbone.