User's Manual
443
An example of the basic configuration of inner router, ABR and ASBR
The following example allocates 4 areas ID for 4 IP address range. Firstly, routing process 109 is activated,
the 4 areas are: 10.9.5.0, 2, 3, 0. The masks of area 10.9.50.0,2,3 designate the address range, but area 0
includes all the networks.
router ospf 109
network 131.108.20.0 255.255.255.0 area 10.9.50.0
network 131.108.0.0 255.255.0.0 area 2
network 131.109.10.0 255.255.255.0 area 3
network 0.0.0.0 0.0.0.0 area 0
!
! Interface Ethernet1/0 is in area 10.9.50.0:
interface ethernet 1/0
ip address 131.108.20.5 255.255.255.0
!
! Interface Ethernet1/1 is in area 2:
interface ethernet 1/1
ip address 131.108.1.5 255.255.255.0
!
! Interface Ethernet1/2 is in area 2:
interface ethernet 1/2
ip address 131.108.2.5 255.255.255.0
!
! Interface Ethernet1/3 is in area 3:
interface ethernet 1/3
ip address 131.109.10.5 255.255.255.0
!
! Interface Ethernet1/4 is in area 0:
interface ethernet 1/4
ip address 131.109.1.1 255.255.255.0
!
! Interface FastEthernet0/0 is in area 0:
interface FastEthernet0/0
ip address 10.1.0.1 255.255.0.0
The functions of network area configuration command are ordinal, so the order of the commands is important.
The router matches the address/mask pair of each interface in order. For detailed information, please refer to
the related content in the reference of related network protocol command in “OSPF command”.
Let’s return to the first network area in the above example. The area ID 10.9.50.0 is configured with an interface
sub-network mask as 131.108.20.0. So Ethernet interface 0 matches. So Ethernet interface 0 only exists in
area 10.0.50.0.
Then come to the second area. Except interface 0, apply the same process on other interfaces, then Ethernet
interface 1 matches. So interface 1 connects to area2.
Continue the matching of other network areas. NOTICE that the last network area command is a special case,
which means that the rest interfaces are all connected to network area 0.
An example of the complex configuration of interior router, ABR and ASBR.
The following example illustrates the configuration of several routers in a single OSPF autonomous system.
Figure 24 is the network topology of the example: