Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 266)

The all-summary-external option directs the router to allow the following LSAs: Router, Network,
Opq-Area-TE and Opq-Link-Graceful while it blocks all Type-3, Type-4 and Type-5 LSAs unless
directed by one of the following keywords:
allow-default - allows only Type-3 or Type-5 default LSAs.
allow-default-and-type4 - allows Type-3 or Type-5 default LSAs and all Type 4 LSAs.
All Type-7 LSAs are always filtered if the ip ospf database-filter command is enabled.
By default, OSPF LSA filtering is disabled on all interfaces.
To remove the filter, enter a command such as the following.
device(config-if-e10000-1/1)# no ip ospf database-filter all out
Assign virtual links
All ABRs (area border routers) must have either a direct or indirect link to the OSPF backbone area
(0.0.0.0 or 0). If an ABR does not have a physical link to the area backbone, the ABR can configure a
virtual link to another router within the same area, which has a physical connection to the area
backbone.
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 fields 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.
• The neighbor router field is the router ID (IP address) of the router that is physically connected to
the backbone, when assigned from the router interface requiring a logical connection. When
assigning the parameters from the router with the physical connection, the router ID is the IP
address of the router requiring a logical connection to the backbone.
NOTE
By default, the Brocade device’s router ID is the IP address configured on the lowest numbered
loopback interface. If the device does not have a loopback interface, the default router ID is the lowest
numbered IP address configured on the device. When you establish an area virtual link, you must
configure it on both of the routers (both ends of the virtual link).
Assign virtual links
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