Dell PowerConnect FCS624S Configuration Guide - Page 975

Configuring OSPF 29 If you have disabled the protocol but have not yet saved the configuration to the startup-config file and reloaded the software, you can restore the configuration information by re-entering the command to enable the protocol (for example, router ospf), or by selecting the Web management option to enable the protocol. If you have already saved the configuration to the startup-config 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-config file containing the protocol 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-config file onto the flash memory. Resetting OSPF The clear ip ospf all command globally resets (disables then re-enables) OSPF without deleting the OSPF configuration information. This command is equivalent to entering the commands no router ospf followed by router ospf. Whereas the no router ospf command disables OSPF and removes all the configuration information for the disabled protocol from the running-config, the router ospf command re-enables OSPF and restores the OSPF configuration information. The clear ip ospf all command is useful If you are testing an OSPF configuration and are likely to disable and re-enable the protocol. This way, you do not have to save the configuration after disabling the protocol, and you do not have to restore the configuration by copying the backup copy of the startup-config file onto the flash memory. To reset OSPF without deleting the OSPF configuration, enter the following command at the Global CONFIG level or at the Router OSPF level of the CLI. PowerConnect#clear ip ospf all Syntax: clear ip ospf all Assigning 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 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. PowerConnect B-Series FCX Configuration Guide 933 53-1002266-01