Cli Inheritance And Precedence For Ospf Version 2: Example - Cisco ASR 9000 Series Routing Configuration Manual

CLI Inheritance and Precedence for OSPF Version 2: Example

area 0
interface GigabitEthernet 0/3/0/0
cost 77
mtu-ignore
authentication message-digest
message-digest-key 1 md5 0 test
!
!
The following example shows the hierarchical CLI structure of Cisco IOS XR software:
In Cisco IOS XR software, OSPF areas must be explicitly configured, and interfaces configured under the
area configuration mode are explicitly bound to that area. In this example, interface 10.1.2.0/24 is bound to
area 0 and interface 10.1.3.0/24 is bound to area 1.
Cisco IOS XR Software Configuration
interface GigabitEthernet 0/3/0/0
ip address 10.1.2.1 255.255.255.0
negotiation auto
!
interface GigabitEthernet 0/3/0/1
ip address 10.1.3.1 255.255.255.0
negotiation auto
!
router ospf 1
router-id 10.2.3.4
area 0
interface GigabitEthernet 0/3/0/0
!
area 1
interface GigabitEthernet 0/3/0/1
!
!
CLI Inheritance and Precedence for OSPF Version 2: Example
The following example configures the cost parameter at different hierarchical levels of the OSPF topology,
and illustrates how the parameter is inherited and how only one setting takes precedence. According to the
precedence rule, the most explicit configuration is used.
The cost parameter is set to 5 in router configuration mode for the OSPF process. Area 1 sets the cost to 15
and area 6 sets the cost to 30. All interfaces in area 0 inherit a cost of 5 from the OSPF process because the
cost was not set in area 0 or its interfaces.
In area 1, every interface has a cost of 15 because the cost is set in area 1 and 15 overrides the value 5 that
was set in router configuration mode.
Area 4 does not set the cost, but GigabitEthernet interface 01/0/2 sets the cost to 20. The remaining interfaces
in area 4 have a cost of 5 that is inherited from the OSPF process.
Area 6 sets the cost to 30, which is inherited by GigabitEthernet interfaces 0/1/0/3 and 0/2/0/3. GigabitEthernet
interface 0/3/0/3 uses the cost of 1, which is set in interface configuration mode.
router ospf 1
router-id 10.5.4.3
cost 5
area 0
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
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interface GigabitEthernet 0/1/0/0
!
interface GigabitEthernet 0/2/0/0
!
interface GigabitEthernet 0/3/0/0
!
Implementing OSPF