Configuring virtual links, Assigning interfaces to an area – Brocade BigIron RX Series Configuration Guide User Manual

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BigIron RX Series Configuration Guide

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Configuring OSPFv3

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Assigning interfaces to an area

After you define OSPFv3 areas, you must assign router interfaces to the areas. All router interfaces
must be assigned to one of the defined areas on an OSPF router. When an interface is assigned to
an area, all corresponding subnets on that interface are automatically included in the assignment.

For example, to assign Ethernet interface 3/1 to area 192.5.0.0, enter the following commands.

BigIron RX(config)# interface Ethernet 3/1

BigIron RX(config-if-e100-3/1)# ipv6 ospf area 192.5.0.0

Syntax: [no] ipv6 ospf area <number> | <ipv4-address>

The <number> | <ipv4-address> parameter specifies the area number, which can be a number or
in IPv4 address format. If you specify a number, the number can be from 0 – 2,147,483,647.

To remove the interface from the specified area, use the no form of this command.

Configuring virtual links

All ABRs must have either a direct or indirect link to an OSPF backbone area (0.0.0.0 or 0). If an
ABR does not have a physical link to a backbone area, you can configure a virtual link from the ABR
to another router within the same area that has a physical connection to the backbone area.

The path for a virtual link is through an area shared by the neighbor ABR (router with a physical
backbone connection) and the ABR requiring a logical connection to the backbone.

Two parameters must be defined for all virtual links—transit area ID and neighbor router.

The transit area ID represents the shared area of the two ABRs and serves as the connection
point between the two routers. This number should match the area ID value.

When assigned from the router interface requiring a logical connection, the neighbor router
field is the router ID (IPv4 address) of the router that is physically connected to the backbone.
When assigned from the router interface with the physical connection, the neighbor router is
the router ID (IPv4) address of the router requiring a logical connection to the backbone.

NOTE

By default, the Brocade router ID is the IPv4 address configured on the lowest numbered loopback
interface. If the Brocade device does not have a loopback interface, the default router ID is the
lowest numbered IPv4 address configured on the device.

NOTE

When you establish an area virtual link, you must configure it on both of the routers (both ends of
the virtual link).

For example, imagine that ABR1 in areas 1 and 2 is cut off from the backbone area (area 0). To
provide backbone access to ABR1, you can add a virtual link between ABR1 and ABR2 in area 1
using area 1 as a transit area. To configure the virtual link, you define the link on the router that is
at each end of the link. No configuration for the virtual link is required on the routers in the transit
area.

To define the virtual link on ABR1, enter the following command on ABR1.

BigIron RX(config-ospf6-router)# area 1 virtual-link 209.157.22.1

To define the virtual link on ABR2, enter the following command on ABR2.

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