# OSPF Interface Configuration

To create an OSPF routing instance, you must have an interface configured on your device. An interface is a connection from the device to the network that can be addressed. The interface you need to configure for an OSPF routing instance to be created is a physical port on a NetScreen device.

### To Configure an OSPF Interface

1. On the Interface (OSPF) Page, enter the necessary information:

Bind to Area: Select this option to bind the interface to an OSPF area. Select an area ID from the scrolling list (you must have previously configured the OSPF area in the virtual router).

Protocol OSPF: Select this option to enable OSPF.

Demand Circuit: (For point-to-point and serial tunnel interfaces only) Select this option to configure the interface as a demand circuit. For proper operation, you must configure both ends of the tunnel as demand circuits. The NetScreen device suppresses sending OSPF hello packets and periodic refreshment of LSAs to decrease overhead.

Reduce Flooding: Select this option to prevent periodic LSA updates from being flooded on this interface.

Authentication: Select the authentication method for OSPF communication on the interface.

- None: Select this option to have no authentication of OSPF communication on the interface.

- MD5 Keys: Select this option to use Message Digest version 5 (MD5) authentication. You can enter up to two keys and key IDs. The key can have up to 16 characters and a key ID between 0-255.

- Password: Select this option to use password authentication. Enter a password of up to 8 characters.

Link Type: Select the link type for the interface.

- Broadcast: Select this option to configure the interface for a broadcast network.

- Point-to-Point: Select this option to configure the interface as a point-to-point link.

- Point-to-Multipoint: (For tunnel interfaces only) Select this option to configure the interface as a point-to-multipoint link.

P assive Mode: Select this option to have the interface receive but not transmit OSPF packets. (This option is useful when BGP is also enabled on the interface.)

Priority: Enter the router election priority.

Cost: Enter a value that specifies the desirability of the path associated with the interface, compared to paths of other interfaces. The lower the value, the more desirable the interface path.

Hello Interval: Enter a value that specifies the amount of time, in seconds, that elapse between instances of the interface sending out Hello packets to the network announcing the presence of the interface.

Retransmit Interval: Enter a value that specifies the amount of time, in seconds, that elapses before the interface resends a packet to a neighbor that rejected a previous transmission attempt for the same packet.

Transit Delay: Enter a value that specifies the amount of time, in seconds, that elapses before the NetScreen device advertises a packet received on the interface.

Neighbor Dead Interval: Enter a value that specifies the maximum amount of time that the NetScreen device waits for a response from a neighbor before classifying the neighbor as off-line.

Neighbor List: Specifies an access list to filter the neighbors with which to form adjacencies.

2. Click Apply to save the settings.