White Papers

3. Enter ROUTER OSPF mode.
CONFIGURATION mode
router ospf process-id [vrf]
Process ID is the ID assigned when configuring OSPFv2 globally.
4. Configure the area as a stub area.
CONFIG-ROUTER-OSPF-id mode
area area-id stub [no-summary]
Use the keywords no-summary to prevent transmission into the area of summary ASBR LSAs.
Area ID is the number or IP address assigned when creating the area.
To view which LSAs are transmitted, use the show ip ospf database process-id database-summary command in
EXEC Privilege mode.
DellEMC#show ip ospf 34 database database-summary
OSPF Router with ID (10.1.2.100) (Process ID 34)
Area ID Router Network S-Net S-ASBR Type-7 Subtotal
2.2.2.2 1 0 0 0 0 1
3.3.3.3 1 0 0 0 0 1
DellEMC#
To view information on areas, use the show ip ospf process-id command in EXEC Privilege mode.
Enabling Passive Interfaces
A passive interface is one that does not send or receive routing information.
Enabling passive interface suppresses routing updates on an interface. Although the passive interface does not send or receive
routing updates, the network on that interface is still included in OSPF updates sent via other interfaces.
To suppress the interface’s participation on an OSPF interface, use the following command. This command stops the router
from sending updates on that interface.
● Specify whether all or some of the interfaces are passive.
CONFIG-ROUTEROSPF- id mode
passive-interface {default | interface}
The default is enabled passive interfaces on ALL interfaces in the OSPF process.
Entering the physical interface type, slot, and number enables passive interface on only the identified interface.
○ For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/port/subport information.
○ For a 25-Gigabit Ethernet interface, enter the keyword twentyFiveGigE then the slot/port[/subport] information.
○ For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port/subport information.
○ For a 50-Gigabit Ethernet interface, enter the keyword fiftyGigE then the slot/port/subport information.
○ For a 100-Gigabit Ethernet interface, enter the keyword hundredGigE then the slot/port information.
○ For a VLAN interface, enter the keyword vlan then a number from 1 to 4094 (for example, passive-interface vlan
2222 ).
The keyword default sets all interfaces on this OSPF process as passive.
To remove the passive interface from select interfaces, use the no passive-interface interface command while
passive interface default is configured.
To enable both receiving and sending routing updates, use the no passive-interface interface command.
When you configure a passive interface, the show ip ospf process-id interface command adds the words passive
interface to indicate that the hello packets are not transmitted on that interface (shown in bold).
DellEMC#show ip ospf 34 int
twentyFiveGigE 1/1 is up, line protocol is down
Internet Address 10.1.2.100/24, Area 1.1.1.1
Process ID 34, Router ID 10.1.2.100, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DOWN, Priority 1
594
Open Shortest Path First (OSPFv2 and OSPFv3)