Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 256)

Enable OSPF on the device
When you enable OSPF on the device, the protocol is automatically activated. To enable OSPF on the
device, use the following method.
device(config)# router ospf
device(config-ospf-router)#
This command launches you into the OSPF router level where you can assign areas and modify
OSPF global parameters.
Note regarding disabling OSPF
If you disable OSPF, the device removes all the configuration information for the disabled protocol
from the running configuration. Moreover, when you save the configuration to the startup configuration
file after disabling one of these protocols, all the configuration information for the disabled protocol is
removed from the startup configuration file.
The CLI displays a warning message such as the following.
device(config-ospf-router)# no router ospf
router ospf mode now disabled. All ospf config data will be lost when writing to
flash!
If you have disabled the protocol but have not yet saved the configuration to the startup configuration
file and reloaded the software, you can restore the configuration information by re-entering the router
ospf command to enable the protocol. If you have already saved the configuration to the startup
configuration file and reloaded the software, the information is gone.
If you are testing an OSPF configuration and are likely to disable and re-enable the protocol, you might
want to make a backup copy of the startup configuration file containing the protocol’s configuration
information. This way, if you remove the configuration information by saving the configuration after
disabling the protocol, you can restore the configuration by copying the backup copy of the startup
configuration file onto the flash memory.
Assign OSPF areas
Once OSPF is enabled on the system, you can assign areas. Assign an IP address or number as the
area ID for each area. The area ID is representative of all IP addresses (subnets) on a router port.
Each port on a router can support one area.
An area can be normal, a stub, or a Not-So-Stubby Area (NSSA) :
• Normal - OSPF routers within a normal area can send and receive External Link State
Advertisements (LSAs).
• Stub - OSPF routers within a stub area cannot send or receive External LSAs. In addition, OSPF
routers in a stub area must use a default route to the area’s Area Border Router (ABR) or
Autonomous System Boundary Router (ASBR) to send traffic out of the area.
• NSSA - The ASBR of an NSSA can import external route information into the area.
‐ ASBRs redistribute (import) external routes into the NSSA as type 7 LSAs. Type-7
External LSAs are a special type of LSA generated only by ASBRs within an NSSA, and
are flooded to all the routers within only that NSSA.
‐ ABRs translate type 7 LSAs into type 5 External LSAs, which can then be flooded
throughout the AS. You can configure address ranges on the ABR of an NSSA so that the
ABR converts multiple type-7 External LSAs received from the NSSA into a single type-5
External LSA.
Enable OSPF on the device
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