Technical data

BLADE OS 5.1 Application Guide
152
 Chapter 11: OSPF BMD00136, November 2009
Using the Area ID to Assign the OSPF Area Number
The OSPF area number is defined in the areaid <IP address> option. The octet format is used in
order to be compatible with two different systems of notation used by other OSPF network vendors.
There are two valid ways to designate an area ID:
 Placing the area number in the last octet (0.0.0.n)
Most common OSPF vendors express the area ID number as a single number. For example, the
Cisco IOS-based router command “network 1.1.1.0 0.0.0.255 area 1” defines the
area number simply as “area 1.” On the G8000, using the last octet in the area ID, “area 1”
is equivalent to “area-id 0.0.0.1”.
 Multi-octet (IP address)
Some OSPF vendors express the area ID number in multi-octet format. For example, “area
2.2.2.2” represents OSPF area 2 and can be specified directly on the G8000 as
“area-id 2.2.2.2”.
Note – Although both types of area ID formats are supported, be sure that the area IDs are in the
same format throughout an area.
Attaching an Area to a Network
Once an OSPF area has been defined, it must be associated with a network. To attach the area to a
network, you must assign the OSPF area index to an IP interface that participates in the area. The
format for the command is as follows:
For example, the following commands could be used to configure IP interface 14 for a presence on
the 10.10.10.1/24 network, to define OSPF area 1, and to attach the area to the network:
>> # interface ip <interface number>
>> (config-ip-if)# ip ospf area <area index>
>> # router ospf
>> (config-router-ospf)# area 1 areaid 0.0.0.1
>> (config-router-ospf)# enable
>> (config-router-ospf)# exit
>> #
interface ip 14
>> (config-ip-if)# ip address 10.10.10.1
>> (config-ip-if)# ip netmask 255.255.255.0
>> (config-ip-if)# enable
>> (config-ip-if)# ip ospf area 1
>> (config-ip-if)# ip ospf enable