28.2.4 Configuring an Area Border Router

Points to note

You can use the area range command with the not-advertise parameter specified to prevent the networks in the prefix range from being advertised outside the area.

For a given area, you can specify more than one address range for route summarization and for route advertisement suppression. A router or network in the area can be assigned an address not included in any of the address ranges you specify. However, when building a network, by allocating addresses to suit the topology first and then configuring summarization for address ranges in a manner appropriate for the topology, you can efficiently reduce the amount of OSPFv3 routing traffic without impairing the ability of the protocol to select the best routes.

This subsection provides an example of configuring route summarization for an area border router associated with areas 0 and 1.

Command examples

1. (config)# ipv6 router ospf 1

   (config-rtr)# area 0 range 3ffe:501:811::/59

   Having learned routes in the range of prefix 3ffe:501:811::/59 in area 0, the router advertises a summarized route to area 1.

2. (config-rtr)# area 1 range 3ffe:501:811::20::/60

   (config-rtr)# exit

   Having learned routes in the range of prefix 3ffe:501:811::20::/60 in area 1, the router advertises a summarized route to area 0.

3. (config)# interface vlan 3

   (config-if)# ipv6 ospf 1 area 0

   (config-if)# exit

   (config)# interface vlan 1

   (config-if)# ipv6 ospf 1 area 1

   Sets up the interfaces on which OSPFv3 is enabled to configure the area border router for areas 0 and 1.