Configuring an OSPF interface

Configure OSPF parameters, such as authentication and priority, so you can control OSPF interface behavior. You can specify the interface as passive, broadcast, or Non-Broadcast Multiple Access (NBMA).

Before you begin

  • Enable OSPF globally.

  • Ensure that the interface exists (the port or VLAN has an IP address).

  • You must know the network OSPF password to use password authentication.

  • Change the VRF instance as required to configure OSPF on a specific VRF instance. The VRF must have an RP trigger of OSPF. Not all parameters are configurable on non-default VRFs.

Procedure

  1. In the navigation pane, expand Configuration > IP.
  2. Click OSPF.
  3. Click the Interfaces tab.
  4. Click Insert.
  5. Select the IP address for the interface from the IP Address list.
  6. To designate a router priority, in the RtrPriority box, type a new value.
  7. In the Type area, select the type of OSPF interface you want to create.
  8. Select the authentication type you want in the AuthType field.
  9. If you chose simplePassword, in the AuthKey box, type a password of up to eight characters.
  10. To change their values, select the current value in the HelloInterval, RtrDeadInterval, or PollInterval boxes, and then type new values.
  11. Click Insert.
  12. On the Interfaces tab, click Apply.

Interfaces Field Descriptions

Use the data in the following table to use the Interfaces tab.

Name

Description

IP Address

Specifies the IP address of the current OSPF interface.

AddressLessIf

Designates whether an interface has an IP address:

Interfaces with an IP address = 0

Interfaces without IP address = ifIndex

AreaId

Specifies the OSPF area name in dotted-decimal format.

For VLANs, keeping the default area setting on the interface causes link-state database (LSDB) inconsistencies.

The area name is not related to an IP address. You can use a suitable value for the OSPF area name (for example, 1.1.1.1 or 200.200.200.200).

AdminStat

Specifies the current administrative status of the OSPF interface (enabled or disabled).

State

Specifies the current state of the OSPF interface. The value can be one of the following:

  • down

  • loopback

  • waiting

  • pointToPoint

  • designatedRouter

  • backupDesignatedRouter

  • otherDesignatedRouter

RtrPriority

Specifies the OSPF priority to use during the election process for the designated router. The interface with the highest priority becomes the designated router. The interface with the second-highest priority becomes the backup designated router. If the priority is 0, the interface cannot become the designated router or the backup. The range is 0–255. The default is 1.

DesignatedRouter

Specifies the IP address of the designated router.

BackupDesignatedRouter

Specifies the IP address of the backup designated router.

Type

Specifies the type of OSPF interface (broadcast or NBMA).

Note:

To make it passive, first create the interface. After interface creation, click VLAN > VLANs to select the VLAN that is created with the OSPF interface. Click the IP tab and select the IP interface that is created with the OSPF interface. Lastly, click the OSPF tab and select Passive for the IfType.

AuthType

Specifies the type of authentication required for the interface.

  • none—Specifies that no authentication required.

  • simple password—Specifies that all OSPF updates received by the interface must contain the authentication key specified in the interface AuthKey parameter.

  • MD5 authentication—Specifies that all OSPF updates received by the interface must contain the MD5 key.

  • sha1—Specifies secure hash algorithm 1 (SHA-1), which is a cryptographic hash function that produces a 160-bit hash value, usually given in a hexadecimal number, 40 digits long.

  • sha-2—Specifies SHA-2, which offers the hash function SHA-256.

    Note:

    sha-2, an update of SHA-1, can offer six hash functions that include SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA 512/256, with hash values that are 224, 256, 384, or 512 bits. However, the current release supports only SHA-256.

AuthKey

Specifies the key (up to 8 characters) required when you specify simple password authentication in the AuthType parameter.

HelloInterval

Specifies the length of time, in seconds, between hello packets. This value must be the same for all routers attached to a common network. The default is 10 seconds.

After you change the hello interval values, you must save the configuration file, and then restart the switch. After the switch restarts, it restores the values and checks for consistency.

TransitDelay

Specifies the length of time, in seconds, required to transmit an LSA update packet over the interface. The default is 1.

RetransInterval

Specifies the length of time, in seconds, required between LSA retransmissions. The default is 5.

RtrDeadInterval

Specifies the interval used by adjacent routers to determine if the router was removed from the network. This interval must be identical on all routers on the subnet and a minimum of four times the Hello interval. To avoid interpretability issues, the RtrDeadInterval value for the OSPF interface must match with the RtrDeadInterval value for the OSPF virtual interface. The default is 40 seconds.

PollInterval

Specifies the length of time, in seconds, between hello packets sent to an inactive OSPF router. The default is 120.

Events

Indicates the number of times this OSPF interface has changed state, or an error has occurred.

LsaCount

Specifies the total number of link state advertisements in this area LSDB, excluding AS-external LSAs.

LsaCksumSum

Specifies the number of link-state advertisements. This sum excludes external (LS type 5) link-state advertisements. The sum determines if a change occurred in a router LSDB and compares the LSDB of two routers.

DesignatedRouterId

Specifies the router ID of the designated router.

BackupDesignatedRouterId

Specifies the router ID of the backup designated router.
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