Connectivity Guide

OSPFv2
OSPFv2 supports IPv4 address families. OSPFv2 routers initially exchange hello messages to set up adjacencies with neighbor routers.
The hello process establishes adjacencies between routers of the AS. It is not required that every router within the AS areas establish
adjacencies. If two routers on the same subnet agree to become neighbors through this process, they begin to exchange network topology
information in the form of LSAs.
In OSPFv2, neighbors on broadcast and non-broadcast multiple access (NBMA) network links are identied by their interface addresses,
while neighbors on other types of links are identied by router-identiers (RID).
Enable OSPFv2
OSPFv2 is disabled by default. Congure at least one interface as either Physical or Loopback and assign an IP address to the interface.
You can assign any area besides area 0 a number ID. The OSPFv2 process starts automatically when you congure it globally and you can
enable it for one or more interfaces.
1 Enable OSPF globally and congure an OSPF instance in CONFIGURATION mode.
router ospf instance-number
2 Enter the interface information to congure the interface for OSPF in INTERFACE mode.
interface ethernet node/slot/port[:subport]
3 Enable the interface in INTERFACE mode.
no shutdown
4 Disable the default switchport conguration and remove it from an interface or a LAG port in INTERFACE mode.
no switchport
5 Assign an IP address to the interface in INTERFACE mode.
ip address ip-address/mask
6 Enable OSPFv2 on an interface in INTERFACE mode.
ip ospf process-id area area-id
• process-id—Enter the OSPFv2 process ID for a specic OSPF process, from 1 to 65535.
• area-id—Enter the OSPFv2 area ID as an IP address (A.B.C.D) or number, from 1 to 65535.
Enable OSPFv2 conguration
OS10(config)# router ospf 100
OS10(conf-router-ospf-100)# exit
OS10(config)# interface ethernet 1/1/1
OS10(conf-if-eth1/1/1)# no shutdown
OS10(conf-if-eth1/1/1)# no switchport
OS10(conf-if-eth1/1/1)# ip address 11.1.1.1/24
OS10(conf-if-eth1/1/1)# ip ospf 100 area 0.0.0.0
View OSPFv2 conguration
OS10# show running-configuration ospf
!
interface ethernet1/1/1
ip ospf 100 area 0.0.0.0
!
router ospf 100
...
534
Layer 3